Concrete mix design and the determination of concrete performance are not merely engineering studies, but also mathematical and statistical endeavors. The study of concrete mechanical properties involves a myriad of factors, including, but not limited to, the amount of each constituent material and its proportion, the type and dosage of chemical additives, and the inclusion of different waste materials. The number of factors and combinations make it difficult, or outright impossible, to formulate an expression of concrete performance through sheer experimentation. Hence, design of experiment has become a part of studies, involving concrete with material addition or replacement. This paper reviewed common design of experimental methods, implemented by past studies, which looked into the analysis of concrete performance. Several analysis methods were employed to optimize data collection and data analysis, such as analysis of variance (ANOVA), regression, Taguchi method, Response Surface Methodology, and Artificial Neural Network. It can be concluded that the use of statistical analysis is helpful for concrete material research, and all the reviewed designs of experimental methods are helpful in simplifying the work and saving time, while providing accurate prediction of concrete mechanical performance. Design of Experiment (DoE) is an effective tool for handling multiple variables in problem solving . The metDoE optimizes the number of samples required to carry out accurate statistical prediction, which explains the effect of each variable on the dependent variables being studied. However, the flexibility of DoE may present a problem, particularly for researchers without sufficient knowledge on the field, and with the absence of a clear methodology in applying the problem-solving task . The appWhile the account of its application varies between studies, certain methodologies are more commonly used than the others. Also, DoE is more frequently used in the prediction of concrete mechanical properties, but other applications, such as density, absorption and cost optimization are also available. Regression analysis is the simplest analytical method, which is employed to understand the relationship between variables. For experiments involving a large size of trials and data, the Taguchi method and Response Surface methodology are favoured to simplify the experimental process itself . AnotherRegression analysis is a basic statistical method that is still widely used to determine the relationship between a single dependent variable with other independent variables. A simple linear regression identifies and expresses two variables that are linearly related to each other. Using the most common tool such as Microsoft Excel or simple graph-plotting software, researchers can study the relationship between variables with little effort. By plotting two variables on graph, the relationship between them can be studied. Variables with linear relationship fall along a line, while non-linear relationship commonly depicts a curved pattern on the plot. If no pattern can be discerned, the variables are independent to each other. While the most basic form of regression is used to test for linear relationship, the regression method is able to test for other relationships by transformation as shown in 2 value above 0.980 for all three conditions in the study, indicating that the regression model could be used for prediction with minimal deviation. A similar conclusion on non-destructive test was stated in the study by Kocáb, Misák, and Cikrle [2 does not invalidate more complicated expression, it can be used for achieving great effects within the scope of the study, and it is often sufficient. In another study [2 value ranged from 0.87 to 0.98 for five cases, indicating that concrete age and compressive strength has strong linearity for various curing conditions. The expression allowed the researcher to study the effectiveness of each curing method by comparing the constant coefficient, as well as the slope, which indicates the rate of strength gain. However, it is worth noting that the graphical representation of the result showed the presence of curvature, which can potentially be represented more accurately by a polynomial regression. Hence, in order to consider applications of the method in the future, it is important to consider the sufficiency of a linear model, based on the scope of the study and the degree of potential accuracy improvement if a more complex model is to be used. While simple linear regression is commonly used to express the linear relationship between an independent variable and a dependent variable, the linear relationship between one variable with another can be expressed at a certain power, should the need arises. A modified regression method was performed by Halabe and Ray [2. However, this does not imply that the method is not justified and should never be attempted to verify a theoretical relation.Different variations of regression analysis are widely used in the study of concrete materials. Regression analysis is used as a simple and accurate prediction for experiments similar to past studies, which indicated a linear relationship between variables. It is unclear whether polynomial expression may represent the data more accurately, but linear expression is considered sufficiently accurate for the analysis. Concrete studies that require a correlation expression, involving a single independent and dependent variable, largely utilize the regression analysis. For example, Ramana et al.  applied d Cikrle ; while aer study , a simil and Ray  for the On the other hand, multiple regression analysis has been utilized in concrete studies concerning more than one variable. The number of variables varies from as little as two  to as ma3 versus ratio, in order to cement and percentages replacement. There is also no clear superiority between numeric variables method and relative method. MLR achieved a high accuracy of R2 = 0.907 despite not being the most accurate model. This is the overall trend observed in this review process. For very similar studies on the compressive concrete strength, MLR, logarithmic regression [While performing a comprehensive analysis of different types of regression on the prediction of the strength of High Performance Concrete, Jin, Chen and Soboyejo  used thegression ,45, and gression  were fougression . Hence, gression , SPSS [4gression , and MATgression ,38. TablThe Taguchi method is a modified DoE method invented by a Japanese scientist named Dr Genechi Taguchi in the 1940s, about 25 years after the introduction of the original DoE by R.A. Fisher . The ori2 value of 0.634. With that in mind, this paper reviewed the existing literature and conducted the regression analysis on the data set from each study to verify this phenomena. In each reviewed paper, the experimental regime was duplicated, and the data were manually filled in from the Taguchi Orthogonal Array if it was not presented in the studies. Studies which did not include the parameters in detail were neglected [2 < 0.80), the main effect plot from Taguchi analysis was referred to and any non-linear effect of the variable was transformed into an appropriate function. Then, the mixed regression analysis was conducted. From the output, any variable which was not significant was excluded. Finally, the regression analysis was carried out for the remaining variables and the final R2 was reported, as shown in In most studies that applyi the Taguchi method, researchers are concerned with determining the quantity or proportion of each constituent material that is needed to produce a concrete mix design with the best strength and performance. While this method showed promising results in all of the reviewed literatures, only two studies ,55 attemeglected . MLR wasThe table above shows that the regression analysis on orthogonal array produced satisfactory result for most studies. Porosity , compresThe tables provided for the Taguchi Orthogonal Array were also found to be helpful as most of the reviewed studies have adopted one of the preset arrays without the need for additional technical modification. L-9 matric is useful for small-scale material studies, while modified L-16 matric is suitable for mix design optimization due to the large number of variables influencing the concrete performance. For the studies that require a matric outside of the provided presets, the development of a unique matric, fitting a different number of factor and level is possible. Abbasi et al.  modifiedThe RSM is another DoE method which evaluates the effect and interaction of multiple variables on a dependent variable. Just like the Taguchi method, the primary purpose is to simplify the experimental process and optimize the responses. According to Bradley , the RSMAlthough the RSM offers a sophisticated analysis tool for experimental data, it does not specify the methodology by which data should be collected. Unlike the Taguchi method, which adheres to the Orthogonal Array, multiple methodologies exist for the data collection process. The methods include Box-Behnken Design (BBD), Central Composite Design (CCD), Doehlert Matrix (DM), three-level full factorial designs, and others. Three-level factorial design involves conducting experiments on all possible combinations, and hence, has limited applications in relation the RSM, as the number of experiments required becomes too large when the number of factors increases, causing low efficiency in data collection . The effp-value < 0.05 to determine the significance of each variable in the analysis, researchers have attempted to adopt lower confident levels to include more variables in the final model. For example, Mrudul et al. [p-value <0.10) in t-test, but the final model remained satisfactory with R2 value above 0.90, which indicate that 90% variation in compressive strength of silica infused recycled aggregate concrete can be attributed to the variables. Meanwhile, Vasudevan, Poornima, and Balachandran [2 value of the original RSM model was 0.980, but after dispensing terms with p-value above 0.15, the R2 became 0.975, which was a negligible drop even though the process eliminated 3 terms from the RSM model. This hints that the standard convention of 95% confidence interval does not need to be absolutely followed when optimizing equations. The ability of the RSM in predicting the concrete properties is satisfactory. Even though the RSM only presents data in the second-order polynomial or quadratic form [In certain studies, workability of concrete, as indicated by slump test result, was selected as an dependant variable of RSM analysis. While the workability of concrete can be measured at the early phase of concrete production, the inclusion of slump value is mainly done to study the inflence of replacement material on concrete workability through the RSM model. For example, in the study of concrete with electronic waste  and rubbl et al.  used 90%chandran  optimizetic form , reviewstic form . In additic form  and watetic form  of concrThe Neural Network is a web of interconnected neurons, which conduct parallel processing during the thinking process, and where millions of neurons transmit signals to each other to process information . In the earchers ,90 when earchers , and notearchers .Another important consideration of ANNs is to specify the amount or portion of data on training, validation, and testing of the perceptron. Algorithm training is important, and incorrect or insufficient training will result in poor quality of the model. Several researchers applied the training algorithm rather than the manual selection. K-fold cross validation ,95 and L2 value, is superior to regression analysis [2 value than the model produced from ANNs. This may be attribute to the low number of data in the experiment , as ANNs perform better when more data is being fed. In addition, the R2 value should not be the sole factor used to decide on the best model. In another experiment on recycled aggregate concrete [2 values but the Root Mean Squared Error (RMSE) of the ANNs model was significantly lower than the other models.ANNs are widely used to predict the concrete compressive strength with number of variables more than the commonly used for other DoE methods. One unique application of ANNs is that the advanced computing power of the method allows the meta-analysis of several concrete studies that use the same replacement materials. Gupta  who collanalysis ,90, inclanalysis . Howeveranalysis , the resconcrete , both RSTo model the concrete compressive strength at a certain age, most studies tend to include the constituents of concrete as the variables, and a model is produced for every date concerned. However, an alternative methodology was conducted by Chopra et al. , wherebyThis paper discussed the concept and applications of the DoE methods in the research regarding concrete mechanical properties. In the field of concrete materials, the concrete performance is affected by a multitude of variables, which makes it impractical to study and experiment an innovation through sheer experimentation. DoE offers a solution for minimizing the number of experiments to conserve time, money and labor, as well as provide a superior data analysis methodology that can give accurate results and predictions. When applying DoE, and especially in complex analysis, it is important to ensure the physical meaning of the variables is sound, instead of merely seeking the strongest correlations, as mathematical correlation does not necessary imply logical causation. The mixed regression analysis is a versatile technique that can provide an expression for the properties of sustainable concrete, through either single or multiple variables. The combination of linear and logarithmic functions is widely used in the modelling of concrete properties. Regression analysis has adequate accuracy, but it is less accurate compared to other advanced techniques. The Taguchi method is applied to minimize the number of experiments required to a huge extent using the Orthogonal Array. It is effective and easy to use, provided that the number and level of variables fit into the array. L-9 matrix is suitable for the study on replacement of concrete materials while modified L-16 matrix is largely used for design mix optimization. The RSM is mainly used in concrete material studies with two or three variables to produce response surface which is similar to information exist in the design standard. CCD is a commonly used method in organizing the data for the experiment. Last, ANN is an advanced method of analysis that requires the use of cross-discipline knowledge in concrete-related studies, but it can provide a highly accurate expression when a sufficiently large amount of data is available. In studies concerning sustainable concrete, DoE methods have shown successful results concrete properties, the effect of replacement materials, and the development of concrete mix design. However, mechanical properties of concrete are currently the dominant application of DoE with application on other properties to be explored.


N = 88). The results showed that the largest discrepancies of used and appreciated aids could be found concerning the opportunity to discuss decisions with relatives, the possibility to take notes, the use of objects, pictures and a keyword list. Female patients indicated a lower PE-fit. These findings highlight discrepancies between the use of specific aids and the wishes of patients and call for thoughtful use of aids during consultations with geriatric patients.As some cognitive functions decline in old age, the ability to decide about important life events such as medical treatment is endangered. Environmental support to improve the comprehension of health-related information is therefore necessary. With a small-scale explorative approach, the present survey study aimed at investigating person-environment fit (PE-fit) of support provided during medical consultations. This fit was calculated by assessing the match between aids provided by five medical practitioners during medical consultations and aids most appreciated by the geriatric patients ( Article 1 of the universal declaration of human rights states that all human beings are born free and equal in dignity and rights. The freedom of all humans is also embedded in German constitutional law; however, freedom is a broad term and requires further specification.The global term freedom refers to “freedom of actions” . The cenHealthy aging is related to changes in brain and cognition and, whilst differing between individuals, often results in cognitive decline. These functional cognitive changes can result in lower selective information processing speed, diminished cognitive flexibility and in difficulties with so-called dual tasks in which attention must be shared , 23. As Several authors described the particular vulnerability of geriatric patients in the informed consent process , 14 due extended discussion and enhanced consent form lead to the best effects on the subjects’ understanding of information [Past studies on aids for enhancing the informed consent for a variety of patient groups have yielded mixed results. Meta-analyses on this topic indicate that aids from the categories ormation , 15. Liuormation  investigormation  demonstrormation  also conormation .However, previous studies did not assess the match between the aids patients would generally appreciate and the aids they were provided with. The present study tried to fill this gap by assessing person-environment fit (PE-fit) of 21 different aids from the 4 categories personal aids, room aids, written aids, and object aids, as recommended by Wied et al. . With reWithin the framework of this exploratory approach, we further examined the PE-fit in relation to psychiatric or neurological pre-existing conditions, and demographic variables such as gender and educational level as predictors of health literacy. Health literacy is considered as “the individual’s capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions” . It is wIn summary, the present study aimed at assessing PE-fit in terms of aids used and appreciated during medical consultation and to examine its relationship with demographic variables.Recruitment took place in spring and summer 2018 through a network of practices collaborating in research of the Institute of General Practice of Goethe University Frankfurt. An invitation to participate in the study was sent out as part of the regular email newsletter. We included general practitioners and dentists because they are the most frequently consulted practitioners. A total of five practices got back to us and indicated a possible number of their geriatric patients they would approach for the study. Afterwards, 30–50 questionnaires including patient information, consent form and stamped return envelopes were sent by mail to the practices. To ensure comparability of our study with research on supported decision-making in dementia, we only included participants older than 65 years as this is the age from which the most common form of dementia, Alzheimer’s dementia, can be diagnosed according to the ICD-10. Further inclusion criteria were that participants were classified as geriatric patients  and hadSD = 6.58), 33% were male, and 55% female, while 12% did not specify their gender. Of the 88 patients, 48 said they had undergone vocational training, 18 had an academic degree, and 22 had a middle school or high school educational level.Overall, 88 patients completed the pen and paper survey and were included in the analysis. The patients were aged between 65 and 92 years with an average of 74.5 years .The participants were asked to answer the survey after they had undergone a medical consultation in the practice. Consultations mostly referred to diagnostic measures, invasive interventions, medical measures, therapeutic treatments or complex interventions, such as chemotherapy and could therefore take different lengths of time. The questionnaire consisted of 72 items and took about 20 min to fill in. After providing details about themselves, their practitioner and the treatment discussed, participants were asked about the medical consultation. Out of a selection of 21 aids  that were based on previous studies  they wert-tests and analyses of variance (ANOVAs). Dependent variables were overall PE-fit as well as the percentage to which aids were not used but would have been appreciated by a patient.Our study took a small-scale explorative approach to investigating patients’ appreciation of specific aids. The PE-fit scores were determined according to the suggestions of Oswald et al. . Every mSD = 10.57%), with a minimum of 55.56% and a maximum of 100%. The mean percentage of aids not used but appreciated was 9.69% (SD = 9.59%) with a minimum of 0% and a maximum of 38.10%.Descriptive results are presented per aid category . Mean overall PE-fit was 84.23%  and women (M = 82.53) was only close to being significant, t(86) = 1.98, p = 0.050, a small to moderate effect size of gender, Cohen’s d = 0.437, was found. Similarly, there was a small gender difference on the percentage of aids not used but appreciated. Women (M = 11.26%) stated significantly more often than men (M = 7.07%) that they would have appreciated an aid that was not used, t(86) = −2.02, p = 0.047. Here, too, a small to moderate effect size of gender was found, Cohen’s d = −0.444.There was no significant association found between overall PE-fit and age, F = 0.658, p =0.520. Similarly, no such differences were found concerning the percentage of aids not used but appreciated, F = 1.382, p = 0.257.Tests on the association between the patients’ educational level, which is related to their health literacy, and their reported overall PE-fit revealed that there were no significant differences between patients with different educational levels, M = 84.68%) and those who did not (M = 84.06%), t(86) = −0.247, p = 0.806. The same was true concerning the percentage of aids not used but appreciated, whereby patients who had a pre-existing psychiatric or neurological condition (M = 9.71%) and those who did not (M = 9.67%) did not differ significantly, t(86) = −0.017, p = 0.986.Finally, no difference in overall PE-fit could be found between patients who had a pre-existing psychiatric or neurological condition (The present study is one of the first to investigate the PE-fit of environmental support during medical consultations. For this purpose, geriatric patients were questioned on the use and their appreciation of 21 aids. The most striking result is the large discrepancy between patients who were provided with the opportunity to discuss medical decision with relatives and those who would have wished to do so. Furthermore, it was observed that many patients would prefer increased use of objects, pictures and a keyword list during the consultation, and that many would have liked the suggestion and the possibility to take notes.Personal aids appeared to be important to almost all participants. Social interaction might help patients feel less insecure, as medical consultations can then be seen as an institutionalized communicative practice in which the doctor tries to minimize a patient’s uncertainty by delivering their advice in a reassuring way .Previous studies have shown that consultation room design has an impact on the interaction between doctor and patient , 27; howAids that are only appreciated by a few patients may not be generally suitable for use during medical consultations. For example, the use of videos may be too time-consuming and therefore more tiring than helpful for patients. Consultations at home would only have been appreciated by one participant. This suggests that geriatric patients find consultations at home too intrusive.Explorative inferential analyses showed that there were no associations between age, educational level or the presence of a pre-existing psychiatric or neurological condition on PE-fit; however, analyses revealed a small to moderate effect of gender on PE-fit. Women on average indicated a lower overall PE-fit and stated more often than men that they would have appreciated an aid that was not used. This implies that the aids used by the practitioners were less in line with what female patients would generally appreciate than was the case with male patients. It could be speculated that the consultation is more adapted to the needs of male patients than to those of female patients. The discussion about the observed gender differences could also be extended to the current debate on discrimination against women in the healthcare system. Either way, these gender effects offer an interesting starting point for investigating patient’s needs and thoughts about aids and their use in more depth.The present study has some limitations. Because the sample was so small, it cannot be seen as representative. Only five practitioners responded to our invitation to the study, which is why we must assume that they form a very selective group who are specifically interested in the topic. The participants, being mobile enough to visit the practice and competent enough to fill in the questionnaire, also form a selective group. Furthermore, we did not control for our inclusion criterion geriatric patient but delegated this judgement to the recruiting practitioners. We acknowledge that the selectiveness of both practitioners and patients as well as the patients’ individual medical history, diagnosis and relationship with the practitioner might have influenced the patients’ responses in the questionnaire; however, the selectivity of the groups, and the discrepancy that nevertheless exists between used and appreciated aids, suggest that in the average population of geriatric patients and practitioners, the need for aids and research on PE-fit may be even higher. Moreover, 76.6% of the patients reported having a psychological, psychiatric, neurological or medical condition. It is quite possible that these conditions might be related to preferences for certain aids in different ways, for example less appreciation for written aids or visual aids when vision is impaired. Further research should consider these links.Furthermore, it should also be mentioned that for the calculation of the PE-fit, the number of aids used by a practitioner did not matter. Thus, a practitioner who used very few aids could score just as high on overall PE-fit as a practitioner who used a lot of aids, but whose aids did not match the ones appreciated by their patient; however, the number of aids used might indeed be relevant for the general perception of support. A more detailed analysis of practitioners’ habits of using aids might therefore also be useful in a possible replication of the study.As we did not specify whether “not appreciated” meant that patients did not see the aid as necessary or that they actually disliked it, our study lacks detailed information on patients’ associated feelings and thoughts. Future surveys asking patients for their perspectives and reasons for their preferences may be useful. Moreover, effectiveness of aids, perhaps operationalized as patients’ understanding of treatment information or satisfaction with the decision, could not be determined.Our findings enable some recommendations for future research and practice. Family members should be integrated more often into medical decision-making procedures involving old patients. As many patients appreciate personal and room aids, medical practitioners should continue to personally introduce themselves, offer a personal greeting, lead the conversation while seated, maintain eye contact, take their time, divide information into sections and repeat important information, avoid technical terms, and make sure the consultation takes place in a tidy, clean and bright room. Practitioners should offer patients the opportunity to discuss decisions with relatives, suggest that their patients take notes, and consider the use of object aids, such as a keyword list with bullet points on the most important information, pictures, and objects such as the package of a drug when pharmacological treatment is discussed.Although PE-fit was mostly moderate to high, the present study unveiled some discrepancies between aids used and those appreciated by patients. This implies that while the use of aids is important, there appears to be no universal solution for all patients. A possible approach could be to ask patients about their preferences and needs before implementing aids. In this case, it must be evaluated whether this supports patients or whether the offer could overwhelm them.Possible replication studies should include a higher number of practitioners and a bigger overall sample. The type of practitioner and the type of treatment discussed should be included in the analysis in order to detect specificities of PE-fit for different disciplines and diagnoses. Future research should test the effect of aids on a variety of health-related outcome measures.Practitioners should keep up to date with the many ways to support old patients during consultations and use aids in an evidence-based way.Practitioners should stay aware that personal aids such as a personal introduction, the repetition of important information, or the division on information into short sections, are important to most patients and should be routinely implemented.A majority of patients would appreciate the opportunity to discuss medical decisions with relatives. Practitioners should try and enable them to do so.In conclusion, the present study showed that there are discrepancies between the aids that general practitioners and dentists use and those that their geriatric patients would wish for. We hope the present study can serve as a basis for the generation and testing of further hypotheses concerning the use of certain aids during consultations in medical practice.


Cognitive impairment is common in Parkinson’s disease (PD) and highly associated with loss of independence, caregiver burden, and assisted living placement. The need for cognitive functional capacity tools validated for use in PD clinical and research applications has thus been emphasized in the literature. The Virtual Reality Functional Capacity Assessment Tool (VRFCAT-SL) is a tablet-based instrument that assesses proficiency for performing real world tasks in a highly realistic environment.The present study explored application of the VRFCAT-SL in clinical assessments of patients with PD. Specifically, we examined associations between VRFCAT-SL performance and measures of cognition, motor severity, and self-reported cognitive functioning.The VRFCAT-SL was completed by a sample of 29 PD patients seen in clinic for a comprehensive neuropsychological evaluation. Fifteen patients met Movement Disorders Society Task Force criteria for mild cognitive impairment (PD-MCI); no patients were diagnosed with dementia. Non-parametric correlations between VRFCAT-SL performance and standardized neuropsychological tests and clinical measures were examined.VRFCAT-SL performance was moderately associated with global rank on neuropsychological testing and discriminated PD-MCI. Follow-up analyses found completion time was associated with visual memory, sustained attention, and set-switching, while errors were associated with psychomotor inhibition. No clinical or motor measures were associated with VRFCAT-SL performance. Self-report was not associated with VRFCAT-SL or neuropsychological test performance.The VRFCAT-SL appears to provide a useful measure of cognitive functional capacity that is not confounded by PD motor symptoms. Future studies will examine utility in PD dementia. Parkinson’s disease (PD) is a progressive neurodegenerative disorder involving both motor and non-motor symptoms. Cognitive deficits are common in PD, with an approximate 40%meeting criteria for mild cognitive impairment (PD-MCI) and 80%or more progressing to Parkinson’s disease dementia (PDD) over the course of illness . ImpaireIn movement disorder clinics, neuropsychological evaluations are useful for determining whether subjective reporting of decline in memory and cognition by the patient is supported by objective findings of deficits on standardized tests . Test peSeveral informant-based questionnaires have been validated for use in assessing cognitive functional capacity in PD. However, knowledgeable informants are not always present during clinical evaluations, and these ratings can be biased by caregiver mood, burden, and other factors . AnosognSeveral standardized tests of real-world functioning have been developed and explored in PD populations. The Everyday cognition battery assesses medication use, financial planning, and food preparation and nutrition skills through a series of tasks that involve reading, episodic memory, working memory, and inductive reasoning . It has The Virtual Reality Functional Capacity Assessment Tool (VRFCAT) is a tablet-based task that requires examinees to complete a series of real-world tasks in a virtual-reality environment . The tasAn abbreviated version of the test, the VRFCAT-SL was recently developed that reduces completion time to less than 15 minutes in healthy older adults. Aside from technical assistance that might be needed from the examiner, the task is self-administered and scoring is automated. Normative data with gender, age, and education correction are available from the publisher. These features, along with elimination of additional test materials and manipulatives, make the VRFCAT-SL particularly attractive for assessing functional abilities within the context of a comprehensive neuropsychological evaluation. There are also multiple versions available to reduce practice effect with serial testing.We recently began administering the VRFCAT-SL to PD patients referred for clinical neuropsychological evaluations to assess functional capacity. The present study is a retrospective chart analysis to explore utility of the VRFCAT-SL as measure of functional capacity in clinical neuropsychological evaluations of subjective cognitive decline in PD. Specifically, we sought to determine whether VRFCAT-SL performance measures were associated with scores on standardized neuropsychological tests and sensitive to cognitive impairment in PD. We also wanted to assess the potential impact of motor disturbances on ability to complete the VRFCAT-SL. Finally, we examined whether the use of a standardized self-report scale for impact of cognition changes on instrumental ADLs, the Parkinson’s disease Cognitive Function Rating Scale (PD-CFRS) , would pThis retrospective chart review was approved by the Human Subjects Protection Program at the Medical University of South Carolina, Pro00098834.Participants were 30 consecutive patients followed in a tertiary care Movement Disorders clinic for idiopathic PD at an academic medical center who were referred for neuropsychological evaluation. PD diagnosis was made according to UK Brain Bank criteria by a fellowship-trained movement disorder neurologist. All patients were referred for neuropsychological evaluation for concerns of cognitive deficits as noted by the patient, informant, or referring neurologist. The VRFCAT-SL was administered to all patients seen during this time period . Administration was paused after these 30 assessments to perform these analyses related to quality assurance. One participant was unable to complete the VRFCAT-SL due to visual impairment (advanced age-related macular degeneration); this individual was also not able to complete other tests with small visual stimuli, the PD-CFRS, and other self-report inventories.The first author (THT) performed all neuropsychological evaluations and administered the VRFCAT-SL. A core battery of tests was administered that included: Mattis Dementia Rating Scale (DRS), Brief Visuospatial Memory Test  , the Movement Disorders Society’s version of the Unified Parkinson’s disease rating scale (MDS-UPDRS) [All standardized testing was completed first, followed by the PD-CFRS, and then the VRFCAT-SL. Performance on the VRFCAT-SL was interpreted qualitatively with respect to implications for functional independence but not was not considered for diagnosis. For all analyses, VRFCAT-SL performances were corrected for age, gender, and education using normative data from the test publisher. For a subset of the sample (S-UPDRS)  Part IIIMeasures of central tendency were examined for VRFCAT-SL outcomes. Corrected scores were strongly skewed  and did not meet assumptions of normal distribution see . Notablyp < 0.002). SPSS version 25 ® was used for all statistical analyses.To examine association between VRFCAT-SL performance and overall cognition, a global cognitive index for each participant was derived based on the average rank (higher = better) for all standardized neuropsychological tests excluding the DRS-2. Similarly, a global score on the VRFCAT-SL was derived based on the average rank for its primary outcome measures . In exploring associations between VRFCAT-SL measures and neuropsychological test performances, the Bonferroni method was used to control for increased Type-I error rate associated with multiple comparisons  and standardized neuropsychological testing. As shown in rho = 0.457, p = 0.043, Trails B Time, rho = 0.472, p = 0.013, and BVMT-R Delayed Recall, rho = 0.444, p = 0.02. The T-Score for VRFCAT-SL Errors was inversely correlated with Inhibition Errors (raw) on the Hayling, rho = –0.561, p = 0.005, indicating greater errors on the VRFCAT-SL were associated with increased errors on the Haylling. T-score for VRFCAT-SL forced progressions was positively correlated with T-score for NAB Naming, rho = 0.499, p = 0.013. All correlations were thus in the expected direction that improved VRFCAT-SL performance was associated with improved neuropsychological test performance. No other correlations were significant at the p < 0.05 level, and none of the associations exceeded Bonferroni correction for multiple comparison . Raw total score from the DRS-2 was not significantly associated with any VRFCAT-SL measure.Relationships between VRFCAT-SL outcome measures and primary neuropsychological outcome measures were also explored. As shown in n = 15) met MDS Task Force Level II criteria for PD-MCI. Independent sample Mann-Whitney U-tests compared performance on VRFCAT-SL outcomes between cognitive status groups. Statistically significant group differences were found for Time, p = 0.001, and Errors, p = 0.005. Statistically significant group differences were not observed for Forced Progressions; however, all 4 patients with a Forced Progression were in the PD-MCI group. Notably, group differences based on cognitive status were also not observed on the DRS-2, p = 0.331.About one-half of the sample . In the PD-MCI group (n = 15), a statistically significant correlation was observed between Time and LEDD, rho = –0.588, p = 0.021, and a trend was observed between Errors and LEDD, rho = –0.477, p = 0.072.Spearman-Brown correlation analyses explored impact of PD motor disturbance on VRFCAT-SL performance. No statistically significant correlations were observed between any VRFCAT-SL measure and duration of illness (years), levodopa equivalent daily dose, or MDS-UPDRS Part III scores. When analyzed separately by cognitive status, a trend was seen for the relationship between Errors and durations of illness, rho = 0.067, p = 0.774. Follow-up analyses did not reveal any statistically significant associations with VRFCAT-SL Time, Errors, or Forced Progressions. Self-report on the PD-CFRS was also not associated with composite rank on the standardized neuropsychological tests, rho = –0.289, p = 0.170. Though falling short of a trend, the direction of this association suggests greater subjective impairment in those with worse performance on neuropsychological testing. Mann-Whitney U-tests indicated that scores from the CFRS also did not differ between cognitive status groups, p = 0.531. PD-CFRS scores were also not associated with motor disturbance (MDS-UPDRS Part III scores), rho = 0.199, p = 0.428. However, clinically significant associations were observed between PD-CFRS ratings and self-report depression (GDS), rho = 0.621, p = 0.001, and anxiety (GAI), rho = 0.412, p = 0.046.The composite rank for VRFCAT-SL performance was not associated with self-report on the PD-CFRS, Current results support use of the VRFCAT-SL for providing an efficient global assessment of functional cognition in PD patients with subjective cognitive decline. A modest correlation was observed between composite ranks for overall VRFCAT-SL and standardized neuropsychological measures. VRFCAT-SL performance measures also discriminated patients meeting MDS Task Force Level II criteria for PD-MCI from PD patients with normal cognition. Importantly, there were no indications that motor impairment significantly impacts task performance. Taken together, our findings using the VRFCAT-SL are consistent with those previously reported using other functional capacity tools. As with the CTPA, the VRFCAT-SL identified mild cognitive impairment in PD . This stFindings from this study did not support the use of patient’s self-report on the PD-CFRS for assessing impact of cognitive deficits on instrumental ADLs. While Kulisevsky et al. suggest use of the PD-CFRS for self-report , in our One limitation of the VRFCAT-SL with respect to providing a comprehensive functional capacity index in PD is the lack of a medication management task. Most patients with progressed PD follow a complex regimen involving variable doses of one or more dopamine replacement therapies throughout the day, as well as medications that might be taken for non-motor symptoms and other health conditions. The ability to reliably take medications as prescribed has presents a significant cognitive challenge and obvious relevance to overall functioning. Lack of a medication condition is also a weakness of the UPSA and CTPA. The ECB includes several items that require participants to remember information contained on a pill bottle and answer multiple choice questions but does not measure ability to actually follow a medication schedule. As such, this would appear to be more of a test of attention, learning, and memory with medication-themed stimuli, rather than a medication adherence task, per se. The Medication Management Abilities Assessment (MMAA)  was specA methodological limitation of this study is that the provider (THT) performed neuropsychological testing, administered the VRFCAT-SL, and interpreted test performances. While cognitive status was based on clinical history and standardized neuropsychological testing, the possibility of diagnostic bias from observing VRFCAT-SL performance must be considered with respect to sensitivity and specificity estimates for discriminating PD-MCI. This study also included a relatively small sample of PD patients, and only a subset of participants had MDS-UDPRS Part III scores thus limiting generalizability. Future studies with neuropsychological evaluation independent of VRFCAT-SL administration are therefore recommended.In the course of this study, no patients were found to meet MDS Task Force criteria for dementia in PD. This is not particularly surprising given that referring Movement Disorder neurologists generally request neuropsychological testing to identify mild cognitive impairment, while diagnosis of dementia is based on more obvious deficits and loss of independence. Future studies are thus needed to determine whether this can be used effectively in PD dementia populations.Taken together, the results from this retrospective chart review provide provisional support for the VRFCAT-SL as an efficient tool for obtaining a global estimate of cognitive functioning in moderately advanced PD. Compared to other standardized functional capacity tools that have been used in PD, the tablet-based VRFCAT-SL eliminates the need for manipulatives, reduces administration and scoring complexities, and appears to be less burdensome with respect to time. Further investigation is required to evaluate test-retest reliability and determine whether it provides an objective measure of functional cognitive capacity across the full spectrum of disease progression.Click here for additional data file.


Corrosion creates a significant degradation mechanism in reinforced concrete (RC) structures, which would require a high cost of maintenance and repair in affected buildings. However, as the cost of repairing corrosion-damaged structures is high, it is therefore pertinent to develop alternative eco-friendly and sustainable methods. In this study, structural retrofitting of corroded reinforced concrete beams was performed using bamboo fiber laminate. Three reinforced normal weight concrete beams were produced, two of which were exposed to laboratory simulated corrosion medium, and the remaining one sample served as control. Upon completion of the corrosion cycle, one of the two corroded beams was retrofitted externally with a prefabricated bamboo fiber laminate by bonding the laminate to the beam surface with the aid of an epoxy resin. The three beams were subjected to loading on a four-point ultimate testing machine, and the loads with corresponding deflections were recorded through the entire load cycle of the beams. Finally, the mass loss of embedded steel reinforcements was determined to measure the effect of corrosion on the beams and the steel. The result showed that corroded beams strengthened with bamboo laminates increase the bearing capacity. Using a single bamboo laminate in the tensile region of the corroded beam increased the ultimate load capacity of the beam up to 21.1% than the corroded beam without retrofit. It was demonstrated in this study that the use of bamboo fiber polymer for strengthening destressed RC beams is a more sustainable approach than the conventional synthetic fibers. Reinforced concrete is a widely used composite construction material that employs steel usage due to its remarkable tensile properties that help in the overall performance of the composite material. Steel has strong tensile properties, which allows it to be used in reinforced concrete and makes its relationship with concrete a mutually beneficial one. However, steel corrosion compromises this relationship and threatens to negatively change this relationship . Steel i2 and chlorine make their way to the steel reinforcement. Corrosion induces many concrete damages such as spalling, cracking, debonding; delamination; reduction of the yield, ductility, and steel reinforcement cross-sectional area; and premature failure [2O3) around the reinforcing steel. However, corrosive agents (CO2 and chlorine) eliminate the oxide film by penetrating through the voids formed in the concrete by either lowering the PH value of the concrete or attacking the oxide film. This allows the embedded steel to contact moisture and oxygen, consequently causing the steel to corrode [Corrosion is launched on RC structures when damaging elements to steel such as CO failure ,4. Due t corrode ,6.Due to the need to keep structures safe and functional from structural deterioration, especially corrosion, various strengthening, and retrofitting techniques have arisen to solve such problems. The usage of fiber-reinforced polymer (FRP) composites to strengthen and reinforce structural elements has become increasingly popular over recent years over traditional strengthening methods  . FRPs arSynthetic or artificial fibers such as carbon, aramid, and glass, amongst many, are the most widely used fibers employed as FRP reinforcements in strengthening and retrofitting concrete structures . The mosThese problems have led to the exploration of viable alternatives of natural and renewable resources to replace these materials that are not environmentally friendly. Natural fibers are good substitutes to synthetic fiber composites, especially in strengthening and retrofitting materials in the construction industry . The empBamboo is an adequate option amongst natural fiber as a composite in strengthening and retrofitting concrete elements. Its high tensile strength; cheaper cost compared to CFRP, wood, and steel; rapid growth; and mechanical and durability properties are some of the characteristics that are making this plant fiber gain increasing interest with researchers and engineers ,21,22,23Some past studies have investigated the use of natural fibers as a composite to strengthen reinforced concrete (RC) beams in flexure and shear ,25,26,27Thus, the use of bamboo can be seen as a natural solution to the structural performance of concrete. In the current study, bamboo fiber laminate is being used to strengthen the structural beam exposed to corrosion in a laboratory simulated corrosive medium. In this study, a composite material of epoxy resin reinforced with long unidirectional bamboo fibers, to be used to strengthen corroded RC beams in flexure, was developed. A tensile test was performed on the fabricated composite to determine its tensile strength following the ASTM standards. The strengthening extent of the bamboo fiber-reinforced polymer (BFRP) laminate on RC beam was determined experimentally by carrying out a four-point bending test on a BFRP-strengthened RC beam, with reference to an un-strengthened beam. Comparisons were drawn between the experimental results of both the un-strengthened and strengthened beams in terms of the load versus deflection plot. Assumptions adopted in this study were presented. The results and outcome of this research are expected to serve as a guide to concrete designers and constructors for solving problems relating to concrete member corrosion in practice.The corrosion phenomenon causes a greater volume of the rust in concrete composite; thus, it results in a most detrimental effect of cracking and spalling of the concrete cover due to tensile stresses developing ,29. AlonThe use of the hybrid technique between near surface mount (NSM) and the external bond (EB) technique has shown to mitigate disadvantages of each technique as mentioned in the literature review, making it more desirable. Yet, concerning FRP composites, especially with natural fibers, limited research explores this technique. Though minimal studies exist relating to the use of strengthening techniques employed retrofitting beams with bamboo fiber, the studies which deal with it use the EB technique due to ease of use and lower costs.Bamboo as a reinforcing material is utilized in various forms such as mats, fibers, powder, and strips, with strips shown to have the better cohesive ability on structural members. Yet, most studies explore bamboo as a reinforcing material in retrofitting structural members, primarily as fibers ,22 and fThe experimental study constituted casting three reinforced concrete (RC) beams. The first beam was the control beam, the second beam was corroded, while the third beam was corroded and retrofitted with a single bamboo laminate at the tensile underside of the third beam. The dimensions of all the specimens were identical. Experimental data on deflection and the load of each beam were observed and recorded. The disparity in yield, and ultimate load capacity was investigated.3), and moisture absorbency (8.7%).Two-part epoxy and hardener served as the polymer matrix component in the BFRP laminate. Epikote 816 resin manufactured by Hexion, London, United Kingdom, and Epikure F205  mixed with a 2:1 ratio by weight according to the manufacturer’s specification were utilized. Sikadur 30 LP adhesive manufactured by SIKA corporation, New Jersey, USA, was used to bond the BFRP laminate to the RC beam. The Sikadur adhesive was prepared by blending its two parts (resin and hardener) with a 2:1 ratio. The developed bamboo laminate was fabricated with both 35% and 45% fiber contents by mass. The tensile strengths are as follows—35% fiber laminate (72.8 MPa) and 45% fiber laminate (99.3 MPa).The fabricated bamboo fiber laminate is shown in FRP wrapping on the beam was a one-sided wrap and continuous along the span of the length of the beam.Timber formworks were fabricated using plywood sheets. After the mold fabrication, a low-density polymer termed nylon was applied to the mold walls to avoid its adhesion with cured concrete. The steel bars were then be cut to the required length, bent to the required shape, then tied together, forming the reinforcement cage. The reinforcement cage was then be placed inside the timber mold, ensuring that the desired concrete cover is achieved. The prepared concrete was then poured into the mold and allowed to set. After 24 h, the three beams were demolded and placed in a curing tank for 28 days at 20 °C. The concrete employed to cast the beam specimens was also used to cast three—150 mm concrete cube specimens to determine its 28-day compressive strength based on the BS EN, 12390-3  procedurEach rectangular beam was 300 mm × 200 mm in cross-section and 1200 mm long. The steel reinforcement consisted of two high yield 16 mm diameter steel bars at the bottom and two 12 mm diameter bars at the top. The shear reinforcements consisted of 10 mm diameter bars 150 mm center to center. The clear concrete cover was 25 mm on all sides of the beam specimens. The second and third beams had their reinforcements protruded out of the concrete to establish electrical connections to induce accelerated corrosion. A section of the beam showing reinforcement details is presented in m = mass loss, a = atomic mass of iron (55.85 gr), t = corrosion process time, I = corrosion current, n = reacting electrode valence for the material (which for steel is 2), and F = faraday’s constant . Two beams were immersed to 75% of their length in a tank containing 6% of industrial salt solution (NaCl), which was subjected to wet and dry cycles . This method is a combination of both the impressed current technique and alternate wetting and drying technique. The beams were subject to a constant electric current that was applied during the wetting period. The mass-loss rate of tensile bars is regarded as corrosion rate and will be estimated employing using Faraday’s law. The equation expressing mass loss is represented by:All the specimens were tested in a 50 tons universal testing machine (UTM), manufactured by Dongguan HongTuo Instrument Co.,Ltd., GuangDong, China. After the 28-day curing at 20 °C was done, the beams were washed, and their surface was cleaned and checked for cracks. The second and third beams were then immersed about 2/3 of a 200 L drum containing 0.6 mol NaCl solution, which was then left for a week. The tensile reinforcements served as the connecting point for the anode, while an external reinforcement served as the cathode. Alternate wetting and drying were also used in inducing accelerated corrosion to save energy costs for three weeks with two weeks of wetting and a week of drying. During testing, the beams were mounted on steel supports with a clear span of 1050 mm. The load was then applied with a 50 ton UTM at 1 ton increments. The total applied load was a combination of the weight of the spreader beam and the load applied from the UTM. Three dial gauges were placed below the beam at the midspan and below the load application points to monitor the beam’s deflections. Deflections were recorded after each load increment. The ultimate load-carrying capacity of all the beams and the nature of the failure are given in The load-deflection curve for the control beam includes a linear response of load in the range between 65–80 kN. The first apparent crack was seen at a load of 84 kN. After 120 kN, flexural load cracks showed and widened as loading increased. The maximum load was 180.4 kN, as shown in Evidence of corrosion on beams is presented in However, due to combining two methods of corrosion acceleration process, namely cyclic wet and drying with the impressed current technique, the mass loss was derived by comparing the final weight or mass of the tensile steel with the original weight of the steel. The control beam was used as a reference and the weight were compared to determine the mass loss. Weight variation and mass loss in embedded reinforcement bars in beams is presented in As shown in the results, the beam laminate sample performed slightly better than the corroded beam in terms of strength and deflection but less than the control beam. Clearly, the condition of the steel has a significant role in the sample’s strength and deflections. The bamboo laminate was responsible for the corroded retrofitted beam’s strength and deflection increase, as can be deduced from the results.Most research on retrofitted beams dealt with various failure modes from flexural failure, concrete cover separation, and interfacial debonding ,36. ChinHafizah et al.  researchMost beams designed to fail in flexure fail in flexure bending, except for retrofitted beams which exhibit a totally different failure mode, mostly cover debonding ,25. HwoeThe level of corrosion-induced for 33 days in this research was significantly lower compared to the level of corrosion employed by Banu et al. [The retrofitting capacity of bamboo laminate was evidently demonstrated. The bamboo laminate increased the ductility and strength of the corroded beam, thus aiding the load resistance of the beam. The retrofitted beam exhibited strength somewhat close to that of the control beam. Thus, it is practically shown that bamboo fiber laminate has significant structural application on distressed elements.The control beam and corroded un-strengthened beam failed by way of a flexural failure, while the bamboo-strengthened beam exhibited cracking debonding. The sudden change in the cross-section at the end of the laminate contributed to this.The corroded un-strengthened beam exhibited the highest number of cracks, with the control beam exhibiting the lowest number of cracks. Again, the impact of the fabricated laminate is demonstrated by the delay of cack development in the distressed member.This study focused on the structural retrofitting of corroded reinforced concrete beams using bamboo fiber laminate. The following conclusions were drawn from the study:


Space capture actuators face problems such as insufficient flexibility and electrical components that are vulnerable to extreme space environments. To address these problems, a centralized-driven flexible continuous robot based on a multiple scissor mechanism units is proposed in this study. The continuous robot body is composed of two scissor mechanism units coupled in series, and the base container’s three motors to drive the robot. The two scissor mechanism units ensure a wide range of flexible operations and the light weight of the robot. The centralized drive with three motors not only reduces the number of driving sources, but also ensures temperature control and protection of electrical components in the space environment. The kinematics and dynamics of the robot are analyzed, and the workspace and deformation performance of the robot are verified through experiments. Compared with other continuous robots, the proposed continuous robot retains the characteristics of continuous robots in a wide range of flexible operations. At the same time, the configuration is light and a small number of driving sources are used, which is suitable for extreme temperatures, vacuum, radiation, and strict resource-constrained environments in space. With the development of global space science and technology, space has gradually become crowded. The safety of spacecrafts in orbit will be seriously affected by abandoned spacecrafts, various space debris, and other non-cooperative targets. In order to ensure the safety of spacecraft, non-cooperative target acquisition in space has been increasingly investigated by researchers. The space capture actuator is generally used as one of the tool sets, installed at the end of a large space robot arm. In extreme space environments, space capture actuators have the advantages of flexible bending, strong adaptability to non-structural environments, and resistance to extreme space environments. Continuous robots have obvious advantages in the field of non-cooperative target capture due to their high redundant degrees of freedom and flexibility. Continuous robots can use end grippers to capture objects like traditional industrial robots and can use the entire robot body to achieve holding capture as shown in Continuous robots can be subdivided into discrete redundant robots, soft robots, and rigid continuous robots. Compared with discrete redundant robots and soft robots ,2, rigidRope-driven continuous robots are composed of driving ropes and multiple units, and bend as the rope stretched. Walker et al. established the theoretical framework of the bionic continuous robot, and developed a variety of continuous robots that imitate an elephant’s trunk ,4. OCRobConcentric-tube-driven continuous robots are composed of a special alloy, which realizes the bending of the robot by controlling the deformation of the alloy. Wang et al. designed a three-arm concentric tube robot, which was used in nasopharyngeal carcinoma surgery . Rone deFluid-driven continuous robots use gas or liquid in closed cavities to maintain the shape of the robot and are usually lighter weight. Walker et al. developed Air-Octo  and OctAIn summary, continuous robots have achieved many successful applications in specific environments due to their multiple degrees of freedom and flexibility. However, there are still some shortcomings when they are applied to the unstructured space environment . First, To address the problem that existing continuous robots cannot be used in extreme environments in space, this study proposes a centralized-driven flexible continuous robot based on multiple scissor mechanism units. In this work, The proposed space continuous robot is mainly composed of two parts, the base and multistage units. The multistage units are mainly composed of scissor mechanism units, which improve the flexibility of the system. At the same time, due to the application of the linkages, the continuous robot has lightweight characteristics. The base is mainly composed of drive motors and linear slide rails. The base effectively guarantees the precision of electrical parts such as motors, and controllers are protected from the harsh space environment.As shown in When multiple units are connected in series to form the space continuous robot and the corresponding sliding sleeves are moved horizontally on the unit base together, the movement transmission and flexible large-scale deformation are realized.The base is composed of three sets of motors, gears, and linear slides. The motor is connected to the gear to rotate, and the gear drives the linear slide to move. The slider on the linear slide is the power input, and the top panel is slotted to move the slider out. The power input is connected to the sliding sleeve on the scissor mechanism units, which drive the movement of the multistage units. Since all electrical parts are placed in the base, reasonable electromagnetic and temperature control protection of the base can ensure system stability in extreme space environments .In order to simplify the work space of the continuous robot, the robot was regarded as a link-type joint robot. The space continuous robot model is shown in B} relative to the coordinate system {A}; Trans  is the rotation transformation matrix, which represents the rotation operator of the deflection angle θ of the axis k through the origin; the rotation matrix B} relative to the coordinate system {A}; and The motion transformation model of a single scissor mechanism unit was established.From the homogeneous transformation matrix, the transformation matrix of each joint was obtained as:θ of each unit is the same, which means that iθ = θ. According to the D-H method [Because each unit is connected in series to form the continuous robot, the deflection angle H method , a 4 × 4The pose relationship between the robot end and the base was obtained from the pose matrix of the robot end in the coordinate system of the base.The workspace of the space continuous robot was calculated approximately by forward kinematics. On the basis of the analysis of forward kinematics, Monte Carlo method was used to analyze the robot workspace.xp and yp.The position vector of the robot end position was obtained in the base coordinate system by forward kinematics. Then, the Rand  function in MATLAB was used to generate a series of random numbers , and we used random numbers to form random θ was assumed to be , and 100,000 random points were selected. The calculated robot workspace is shown in the The range of XOY plane is shown in X direction and theoretically can reach from −50 to 300 mm in the Y direction. In the actual movement process, the Y direction cannot reach below 0 mm. Due to the limitation of the robot structure, the circular space about 100 mm from the origin cannot be reached. If the number of scissor mechanism units is increased, the robot workspace will further enlarge.The workspace of the continuous robot composed of two scissor mechanism units on the To realize the motion control of the space continuous robot, the relationship between the input variable and the angle change needed to be accurately obtained. The robot is driven by three motors evenly distributed along the circumferential direction at 120°. The movement of the robot is realized by changing the state of the scissors mechanism through the input control. The simplified structure of the scissor mechanism unit is shown in a1, a2, and a3 as the input of the three motors, the motors directly control the changes in a1, a2, and a3. β is the turning angle of the scissor mechanism unit to the origin O’. θ1, θ2, and θ3 are the deflection angles of the sliding rod to the axes of Y’, X’, and Z’, respectively. L is the distance between the center points of two scissor mechanism units. R represents the distance from the unit base to the sliding slot. R1, R2, and R3 represent the cosine value of the trilateral output to the origin O’. ΔR is the change in R with the input.Regarding According to the geometric relationship in Bringing Equations (15)–(17) into Equation (14),θ and θ1, θ2, and θ3 is as follows,According to the structure of the scissor mechanism unit, the relationship between the deflection angle θ can be obtained by combining Equations (20) and (21) as follows,The deflection angle θ can be determined according to the input of a1, a2, and a3.Therefore, the deflection angle The design parameters are shown in θ.In order to verify the robot control performance, the experimental platform shown in The continuous robot turned to the limit value on one side, and then reversed to the limit value on the other side. The motor speed and torque changes with time were recorded as shown in θ did not return to 0°, which also confirmed that the gap had a slight impact on the robot system.The target ball was tracked by the laser tracker to obtain the end position of the robot. The position was converted into the rotation angle of the robot and the fitting curve is shown in In this work, a novel space continuous robot with large range movement ability was constructed. Through the combination of theoretical analysis and experiment, the feasibility of the movement of two scissor mechanism units and its workspace was verified. Due to gravity on the ground, friction has a huge impact on the robot system. Especially when the multi-units are connected in series, the superposition of friction force increases the motor’s burden and the change in rotation angle trembles further. Therefore, the next step will be to consider expanding the number of scissor mechanism units from two to six or seven in a microgravity environment, which will further expand the workspace of the space continuous robot. At the same time, a claw will be designed at the end to verify the holding and capturing performance.This research proposed a flexible continuous robot that can be applied to capture non-cooperative targets in space and has a large range of movement in all directions. With the shortcomings of existing continuous robots, which cannot be used in the space environment, a base containing all of the electrical components of the drive was designed, where temperature control can effectively protect the fragile components from extreme temperatures. The scissor mechanism unit, which combines the scissors mechanism and ball-twist connection mechanism, was used, and the continuous robot was constructed through the series connection of the multistage units and the base. The continuous robot can realize a wide range of three degrees of freedom flexible motion under the drive of three motors. Kinematics analysis of the continuous robot was carried out, and the workspace of the continuous robot was determined. The control parameters of the robot were analyzed, and the motion control variables of the continuous robot were derived. The prototype of the continuous robot and experiment platform was built and the experiments to analyze the relationship between motor speed and torque over time were carried out. The relationship between the deflection angle and time was measured by a laser tracker. The ability of the continuous robot to stretch, bend, and perform large-scale motion were verified, and the existing errors were discussed.


In this study, the compressive performance of sisal fiber-reinforced recycled aggregate concrete (SFRAC) composite, confined with jute fiber-reinforced polymer (JFRP) tube (the structure was termed as JFRP–SFRAC) was assessed. A total of 36 cylindrical specimens were tested under uniaxial compression. Three major experimental variables were investigated: (1) the compressive strength of concrete core , (2) jute fiber orientation angle with respect to the hoop direction of a JFRP tube , and (3) the reinforcement of sisal fiber . This study revealed that the prefabricated JFRP tube resulted in a significant enhancement of the compressive strength and deformation ability of RAC and SFRAC. The enhancements in strength and ultimate strain of the composite columns were more pronounced for concrete with a higher strength. The strength and ultimate strain of JFRP-confined specimens decreased with an increase in fiber orientation angle β from 0° to 45°. The sisal fiber reinforcement effectively improved the integrity of the RAC and reduced the propagation of cracks in RAC. The stress–strain behaviors of JFRP–RAC and JFRP–SFRAC were predicted by the Lam and Teng’s model with the revised ultimate condition equations. During the last decades, the circular economy and sustainable development have aroused growing global consciousness of green urban construction, waste management and the conservation of natural resources. The global construction industry generates an average of 40% of the total waste each year and occupies large volumes of landfills. It is predicted that up to 3 billion tons of construction and demolition wastes (CDWs) were produced in China before 2020. Some countries such as Japan and Germany recycled up to 80% of CDWs, while many other countries have recycled 20–40% of CDWs according to the statistical results up to the year 2018, e.g., 40% for China, 30% for Canada, 28% for Switzerland and 32% for Thailand [By far, recycled aggregate concrete (RAC) technology has been considered the most effective measure in the Waste-to-Energy industry. The aggregates within RAC are produced from CDWs after screening and crushing processes. A certain number of studies have declared that natural defects exist in recycled aggregates as particle shape defects and micro-cracks, which lead to the high-water absorption and crushing index of recycled aggregates ,4,5. SomConsidering the above demerits of RAC, appropriate measures have been undertaken to improve the performance of recycled concrete, such as the application of fiber-reinforced polymers (FRP). The FRP jackets served as an external confinement device and created tri-axial compressive condition to enhance the strength and ductility of confined concrete. Research on FRPs used in recycled concrete confinement have reported considerable improvements in the performance of recycled concrete ,19. TengResearch on FRP tube-confined natural aggregate concrete has shown that the fiber orientation has considerable influence on the performance of the confinement system ,34,35. SIn this study, the compressive performance of JFRP-confined sisal fiber-reinforced RAC containing recycled clay brick aggregates (termed as JFRP–SFRAC) was investigated. The combined use of natural fibers from agricultural waste and recycled aggregates from CDWs would be beneficial for the sustainable development of constructional industry and lower carbon emissions. The influence of jute fiber orientation  was investigated. Besides this, the effects of the compressive strength of internal RAC and the sisal fiber-reinforcement on the axial compressive behaviour of JFRP–SFRAC were studied.The contents and proportions in RA mixtures are changeable due to the diversity of sources and constitutes of construction and demolition wastes. The RAs used in this study contained about 70% mass content of RAs from clay brick waste and 30% mass content of RAs from concrete waste, as shown in Based on the earlier studies on JFRP-confined SFPC , the SFR3 were pre-tested under uniaxial compression according to GB/T50081-2002 [Three groups of unconfined RAC and SFRAC cubic specimens with a size of 150 × 150 × 150 mm081-2002 . Each gr2 was used for the fabrication of the JFRP tube as shown in Bidirectional woven jute fabric with a density of 360 g/mThe hand lay-up approach was used for JFRP tube prefabrication and the prefabricated JFRP tubes are shown in A total of 36 composite columns  were constructed for the uniaxial compression tests. The size of all specimens was diameter × height = 150 mm × 300 mm. The tested variables included: (1) the inclusion of sisal fiber in RAC ; (2) thMonotonic axial compression on all the specimens was realized by using an MTS testing machine with capacity of 2000 kN as shown in σ = 0 to σ = cof and stopped at σ = 0.2cof in the descending stage. The surface cracks in unconfined RAC appeared until the axial stress reached σ > 0.4cof and developed with cover concrete flaked off. The failure mode of unconfined RAC cylinders exhibited several thorough longitudinal cracks and flaked off bulk concrete rubble, as illustrated in The failure modes of each kind of specimens are shown in σ reached 0.9ctf, when a tearing sound was heard. All JFRP–RAC specimens ruptured with one single longitudinal thorough crack of the outer JFRP tube with a width of around 1.1–1.3 cm, and the inner concrete was crushed thoroughly with several short longitudinal cracks as shown in For the JFRP–RAC specimens, no obvious damage was observed until the axial stress concrete . Thus, bThe lateral strain–axial strain relationships of JFRP–RAC and JFRP–SFRAC were given in in β see a,b. ThisThe tested results are summarized in The strength enhancement ratio he study . The axiThe ductility ratio Numerous predicted stress–strain models have been developed for traditional FRP-confined circular concrete columns ,42. As mconcrete . It is iconcrete , Spoelstconcrete , Fam andconcrete  and Chunconcrete  used theconcrete . The linnd Monti . The axind Monti  as Equatnd Monti .The comparison between the predicted values and the tested values of compressive strength and ultimate strain of JFRP–RAC and JFRP–SFRAC is shown in Based on the discussion on the ultimate condition equations, Lam and Teng’s stress–strain model was used in the prediction of the stress–strain response of JFRP–RAC and JFRP–SFRAC as Equation  . It shouThe lateral-to-axial strain equation as Equation (6) , which iBased on the comparison of the lateral-axial strain response between the predicted values and tested values, the coefficient (1)The confinement of JFRP increased the compressive strength of RAC by 28~68%. The compressive strength of JFRP-confined specimens with 0°, 30° and 45° jute fiber orientations decreased in sequence. The reinforcement of sisal fiber slightly increased the compressive strength of the RAC.(2)JFRP increased the ultimate strain of RAC and SFRAC by around 6.18 to 9.62 times. The ultimate strain of confined specimens with 0°, 30° and 45° jute fiber orientations decreased slightly in sequence. The sisal fiber reinforcement in RAC increased the ultimate strain of the composite columns.(3)JFRP confinement was regarded as weak confinement, but the JFRP presented effective confinement because the ultimate strength (4)The sisal fiber reinforcement slowed down the development of the lateral dilation of RAC by reducing the propagation of cracks in the concrete due to the bridging effect.(5)The ultimate condition equations of FRP confined natural aggregate concrete exhibited deviation in prediction of the ultimate conditions of JFRP–RAC and JFRP–SFRAC. The predicted stress–strain behavior by Lam and Teng’s model with the revised ultimate condition equations demonstrated good agreement with the tested results.(6)The predicted lateral–axial strain model used in the study presented a slight overestimation of the dilation of JFRP–RAC, and the coefficient In this study, the experimental investigation and theoretical analysis of JFRP tube-confined RAC and SFRAC under axial compression were conducted. Overall, jute FRP confinement and sisal fiber reinforcement have an active effect on the strength and ductility improvement of RAC. The tests and discussion of the reinforcing mechanism and micro-structure on the composite confined RAC cylinders would be further conducted. The following conclusions were drawn:


The current practice of concrete is thought to be unsuitable because it consumes large amounts of cement, sand, and aggregate, which causes depletion of natural resources. In this study, a step towards sustainable concrete was made by utilizing recycled concrete aggregate (RCA) as a coarse aggregate. However, researchers show that RCA causes a decrease in the performance of concrete due to porous nature. In this study, waste glass (WG) was used as a filler material that filled the voids between RCA to offset its negative impact on concrete performance. The substitution ratio of WG was 10, 20, or 30% by weight of cement, and RCA was 20, 40, and 60% by weight of coarse aggregate. The slump cone test was used to assess the fresh property, while compressive, split tensile, and punching strength were used to assess the mechanical performance. Test results indicated that the workability of concrete decreased with substitution of WG and RCA while mechanical performance improved up to a certain limit and then decreased due to lack of workability. Furthermore, a statical tool response surface methodology was used to predict various strength properties and optimization of RCA and WG. Environmental groups are pushing for the use of RCA and solid wastes such as slag, fly ash, and silica fume in construction projects. The global demand for aggregates for construction is expected to reach 47 billion metric tons per year in 2023 . The solBy volume, RA is made up of 60–70 percent natural aggregates and 30–40 percent aged cement mortar. Parent concrete qualities, workability, mix percentage, and other factors influence the compressive strength and other properties of recyled aggregate concrete ,9,10. WhAs of 2005, the overall worldwide waste glass manufacture valuation was 130 Mt, in which the European Union, China, and the USA manufactured roughly 33 Mt, 32 Mt, and 20 Mt, respectively [2 releases, and depletion of natural resources [2 production associated with cement manufacture.On the other hand, the yearly worldwide cement manufacture has moved 2.8 billion tons and is supposed to rise to some four billion tons each year. Cement production is challenging because of expense rises in energy resources, decreasing COesources ,21,22. Sesources ,24. The 2) to form calcium silicate hydrate (CSH) [Glass exhibits pozzolanic behavior if the particle size is smaller than 75 µm. Silica in glass interacts with calcium hydrates (Ca(OH)te (CSH) . Glass hte (CSH) ,27.It has been concluded that slump is decreased with the addition of waste glass. However, compressive and flexure strength increases up to 20% replacement and then decreases gradually . It has The literature shows that RCA decreases the performance of concrete due to its porous nature, and waste glass has the credibility to be used as a filler material. Therefore, waste glass was used as a filler material that filled the voids of RCA and offset its negative impact on the mechanical performance of concrete. Furthermore, a response surface methodology was used to optimize RCA and WG. The overall study demonstrates that the combined substitution of WG and RCA successfully improved mechanical performance considerably.As per ASTM C150 Type-1, Ordinary Portland cement (Bestway cement Islamabad Pakistan) was used throughout the experimental work to prepare the mix for all batches. The physical and chemical aspects of cement used in this study are shown in 2, Al2O3, and Fe2O3 exceeding 70%.Waste glass was procured from a local shop Kohat Pakistan. The waste glass used in the research was transparent soda-lime glass. The waste glass was ground using ball mill grinding equipment at the PCSIR lab in Peshawar, Pakistan, to reach a particle size equivalent to or less than that of the cement particle size. The physical and chemical aspects of waste glass used in this study are shown in In saturated surface dry conditions, natural river sand was employed as a fine aggregate in all batches. For all batches, normal weight coarse aggregate with a maximum size of 25 mm was employed in saturated surface dry conditions. RCA of 25 mm maximum size was obtained by crushing waste concrete. A variety of tests were carried out on the aggregates to assess its physical properties, and the results are given in RSM is a mathematical and statistical combined technique to estimate relations between a set of input independent variables and output variables . ExperimEquation (2) (second-order model) illustrated the model utilized to estimate the responses and define the relationship between the independent variables.Y = response function (for this study it is the CS),B0 = constant coefficient,Bi, Bii, and Bij = factor of the linear, quadratic, and interactive expressions, respectively .In this study, the quadratic model was used for the prediction.The flow of concrete was determined as per ASTM . The comFor each test, three specimens were tested at 7, 28, and 56 days, and the mean value of the specimens was considered the strength of the experiment. The ASTM C-31  method wWorkability can be defined as the ease of concrete mixing, transportation, placing, and compacting. Workability directly affects the mechanical performance of concrete. More workable concrete results more compact dense concrete . Figure The maximum slump was attained at 0% replacement of waste glass, and the minimum slump was achieved at 30% substitution of waste glass. Research also shows that the workability of concrete reduces with the replacement of waste glass . The decThe pozzolanic reaction of waste glass is responsible for the increased compressive strength. Silica present in waste glass reacts with CH (formed during hydration of cement) and converts it into CSH gel, which provides additional binding property. As a result, strength increases. It can also be observed that improvement in compressive strength at an early stage (seven days) was not significant with the substitution of waste glass, as the pozzolanic reaction proceeds slowly . HoweverA relative analysis of compressive strength concerning 28 days of control concrete is shown in Response surface and contour plot for compressive strength after 28 days of curing are shown in Response surface and contour plot for split tensile strength after 28 days of curing are shown in 2 value greater than 90%.The correlation between compressive strength and split tensile strength with varying doses of waste glass and RCA at different days of curing is shown in The following equation was developed based on experimental tests with different doses of RCA and WG.sp = split tensile strength, fc = compressive strengthf2 value greater than 90%.Experimental split tensile strength predicted from the contour plot and predicted from Equation (3) with different doses of waste glass and RCA at 28 days of curing is shown in A relative analysis of punching strength concerning 28 days of control concrete punching strength is shown n in Response surface and contour plot for punching strength after 28 days of curing are shown in However, concrete made with 20% WG and 40% RCA showed punching strength (9.1 MPa) that was approximately equal to the punching strength of control (10 MPa), as shown in 2 value approximately equal to 90% (88%). The following equation was developed based on experimental tests with different doses of RCA and WG.Correlation between compressive strength and punching strength with varying doses of waste glass and RCA at different days of curing is shown in pu = punching strength, fc = compressive strengthf2 value approximately equal to 90%.Experimental punching strength and punching strength predicted from the contour plot and Equation (4) with different doses of waste glass and RCA at 28 days of curing are shown in In this research, a step towards sustainable concrete was made by incorporating WG and RCA. The substitution ratios of WG were 0%, 10%, 20%, and 30% by weight of cement, and those of RCA were 0%, 20%, 40%, and 60% by weight of coarse aggregate. A detailed conclusion based on test results is given below.As the percentage of WG and RCA increased, the workability of concrete decreased. It was related to the physical characteristics of RCA and WG, which had a larger surface area.WG did not give a significant improvement in strength in the early days (seven days), as the pozzolanic reactions proceeded slowly. However, a considerable improvement in strength was observed at 28 and 56 days of curing.Maximum strength was obtained at 20% substitution of WG. At 28 days of curing, compressive strength was 27% higher than that of reference concrete, while punching strength was 29% higher than that of reference concrete.RCA lowered the mechanical performance of concrete by absorbing more water from it, leaving less or no water available for hydration and workability.A successful statistical analysis (response surface methodology) predicted various mechanical properties and optimized WG and RCA. The optimal doses of WG and RCA (20% WG and 30% RCA) were predicted from the statistical analysis, which showed compressive strength approximately equal to that of the reference concrete. Furthermore, the same doses of WG and RCA (20% WG and 30% RCA) were cast and tested experimentally. It could be observed that the predicted and experimental values were comparable, which validated the predicted results.Finally, the overall study demonstrated that RCA could be successfully utilized with combined substitution of WG without any negative effect on the mechanical performance of concrete. However, it could be observed that combined substitution of WG and RCA up to some extent improved the mechanical performance of concrete. However, concrete is still weak in tension, which results in abrupt failure. Therefore, further research is recommended with addition of steel fibers or natural fibers  to improve the tensile capacity of concrete.


The results indicated that modified rubberized concrete prepared by 5 to 20% WRTCs as a substitute to natural aggregate, provided lower CS and weight lose expose to sulphate and acid attacks compared to control specimen prepared by ordinary Portland cement (OPC). Although the CS were slightly declined at the elevated temperature, these proposed mix designs have a high potential for a wide variety of concrete industrial applications, especially in acid and sulphate risk.Recycling of the waste rubber tire crumbs (WRTCs) for the concretes production generated renewed interest worldwide. The insertion of such waste as a substitute for the natural aggregates in the concretes is an emergent trend for sustainable development towards building materials. Meanwhile, the enhanced resistance of the concrete structures against aggressive environments is important for durability, cost-saving, and sustainability. In this view, this research evaluated the performance of several modified rubberized concretes by exposing them to aggressive environments i.e., acid, and sulphate attacks, elevated temperatures. These concrete (12 batches) were made by replacing the cement and natural aggregate with an appropriate amount of the granulated blast furnace slag (GBFS) and WRTCs, respectively. The proposed mix designs’ performance was evaluated by several measures, including the residual compressive strength (CS), weight loss, ultrasonic pulse velocity (UPV), microstructures, etc. Besides, by using the available experimental test database, an optimized artificial neural network (ANN) combined with the particle swarm optimization (PSO) was developed to estimate the residual CS of modified rubberized concrete after immersion one year in MgSO This observation was attributed to the lower amount of Portlandite in the GBFS mixtures that was consumed by the hydration products to form extra C-A-S-H gels, reducing the formation of the gypsum and ettringite [tringite .2SO4 solution for 365-days. Additionally, the peak intensities of the gypsum at 11.8° and 18.2° were increased and moved nearer to the quartz peak at 27.6° at 27.9°. Bellmann and Stark [nd Stark  reported42− and produced gypsum (indicated by Equation (3)). The generated gypsum reacted with the acuminate calcium hydrate and formed ettringite (shown by Equation (4)), which led to the eventual failure through the crack formation.The calcium hydroxide within the OPC strongly reacted with the penetrated SO2SO4 solution exposure was correlated to the acid accumulation in the concrete matrix and exposure time span. The results revealed that the modified GBFS specimen had higher resistance against acid attack than the normal OPC concrete. The formation of CaSO4.2H2O (13.8%) and Ca6Al2(SO4)3(OH)12·26H2O (29.7%) in the GBFS modified specimen was lower than the OPC concrete (19.7% of gypsum and 13.9% of ettringite) as shown in The degree of the concretes’ damage because of the H4 solution exposure. The results indicate that the bond regions between the cement paste and natural aggregates were affected as a result of WRTCs inclusion. Additionally, larger cracks were observed in the RF5 specimen compared to the modified GBFS specimen.2SO4 solution. The surface morphologies of the OPC-based concrete  and yielded high resistance to disbanding under elevated temperatures compared to the OPC matrix [2 that occurred above 400 °C in the modified concretes [C matrix . The resoncretes .Using multilinear regression, the following equations are proposed to estimate the residual CS and weight loss of modified rubberized concrete exposed to the 500 °C and 900 °C elevated temperatures.2 peak intensities were significantly weaker for the heated treated mixes than those without elevated temperature exposure. Specimens exposed to heat measuring at 900 °C showed comparatively lower XRD peaks compared to specimens exposed to 500 °C heat, indicating that concrete decomposed at a higher rate with higher temperatures. However, the peaks at 18, 31, 37, 38, 41° and 48° for both OPC and GBFS specimens without heating were broader than those exposed to 500 °C. The breakdown which occurs within hydration products at 900 °C had a notable effect on the interface performance. Additionally, the dehydroxylation of calcium hydroxide is observable and results in the complete collapse of the concrete composition, as Ca(OH)2 was degraded and lost its place in the matrix, lowering the peak intensity of the C-S-H gel. The observed reductions may be due to the Portland dehydroxylation in the cement matrix, which was higher for OPC based concrete. This decay was responsible for the reduced performances and strength losses of the concretes at elevated temperatures. GBFS matrix possesses less calcite that leading to less dehydroxylation of the cement. Therefore, it can be concluded that the GBFS modified concrete provided higher fire resistance.4 and H2SO4 solutions.Since the residual CS is the fundamental parameter in the harsh environment, an optimized artificial neural network (ANN) combined with the particle swarm optimization (PSO) was developed to estimate the residual CS of modified rubberized concrete after immersion in MgSOThe multilayer feed-forward network provides a reliable feature for the ANN structure and, therefore, was used in this research. The multilayer feed-forward network comprises three individual layers: the input layer, where the data are defined to the model; the hidden layer/s, where the input data are processed; and finally, the output layer, where the results of the feed-forward ANN are produced. Each layer contains a group of nodes referred to as neurons that are connected to the proceeding layer. The neurons in hidden and output layers consist of three components; weights, biases, and an activation function that can be continuous, linear, or nonlinear. Standard activation functions include nonlinear sigmoid functions  and linear functions  . Once thPSO is a population-based optimization technique inspired by the motion of bird flocks and schooling fish. This optimization technique has many similarities with evolutionary computation methods. PSO is developed initially by a population of random solutions, and subsequently search for the optimum solution through updating generations. Unlike genetic algorithm, PSO has no evolution operators including mutation and crossover and the possible solutions, particles, pass in the domain of the problem following the current optimal particles. This technique has efficiency of both memory requirements and speed.i can be defined by three vectors: ix (position), iv (velocity), and i,Bestx . The particle moves over the search domain defined by its own best known position, i,Bestx, and the best known position of the whole swarm, Bestx. The velocity of the particle can be calculated using following equations.In PSO, a candidate solution called a particle whereas a set of candidate solutions is referred to a swarm. A particle c0 is the inertia weight, r1 and r2 are random numbers generated from U , and c1 and c2 are the cognitive and social acceleration weights, respectively. However, the local best solution i,LBestx was used in this research instead of the global best solution, Bestx, and therefore the Equation (10) was updated as follow [Subsequently the position updated using following equation:s follow .(11)vi,K particles  and itself . In such topology, the connections between particles may randomly change once there was no improvement in the global optimum [For a given individual, the local best solution can determine by the best-known position inside that particle’s neighborhood. In this research the PSO algorithm was used an adaptive random topology in which each particle randomly informs  optimum ,58,59.4 and H2SO4 solutions) followed normal distribution, positively improve the modelling accuracy of ANN.To train and develop a reliable ANN, the percentage of OPC, GBFS, sand, gravel, fine, coarse, and the age of specimens were taken into account on the basis of input variables. The statistical analysis also confirmed that the two output parameters , Average Absolute Error (AAE), Model Efficiency (EF), and Variance Account Factor (VAF) that are defined as follows.R2 to estimate the two output parameters as shown in After examining different topologies, it was found that the network with 7-5-6-2 topology has the lowest value of error in RMSE, AAE, EF, VAF and the highest value of The ANN used in this study was Newff Feed Forward. 80% of the experimental data (out of 54) was used for training, and the rest 20% was used for network testing. To optimize the ANN’s weights and biases, the PSO has been used to provide the least prediction error for trained structure. The properties of the PSO parameters are shown in 4 and H2SO4 solutions, respectively. The results indicate that the PSO-ANN estimated a reliable result for the ratio of observational to computational values, R2, for both input parameters, indicating the high potential and accuracy of the proposed model.The results of PSO-ANN models are shown in 4 and H2SO4 solutions. The following provides the main findings of this research. The results indicated that modified rubberized concrete prepared by 5 to 20% WRTCs as a substitute to natural aggregate, provided lower CS and weight lose expose to sulphate and acid attacks compared to control specimen prepared by ordinary Portland cement (OPC).4−2 reaction with the Ca(OH)2 that produces CaSO4·2H2O, leading to an expansion of the paste matrix and extra cracks generation in the concrete.The results indicate that the CS in modified rubberized concrete experienced a major reduction after immersion in acid solution (by average 95%) compared to sulphate solution (by average 53%). Such a significant reduction can explain by SO4 and H2SO4 solutions, indicating a high durability performance in such aggressive environment.The XRD patterns showed an increase in ettringite and gypsum in GBFS modified concrete after immersion in MgSO2 that occurred above 400 °C.GBFS modified concrete provides the lowest CS loss 15 and 80 MPa in 500 and 900 °C elevated temperatures, respectively. However, by increasing the WRTCs content in modified rubberized concrete from 5 to 30%, the residual CS and weight decreased by 9 and 29% that related to melting of the WRTCs, sluggish evaporation of the water, dehydration of the C-A-S-H gels, and decay of Ca (OH)4 and H2SO4 solutions. In addition, the particle swarm optimization algorithm can also be used as a powerful tool in optimizing ANN weights. By using the optimized weight and bias of PSO-ANN, it is possible to design modified rubberized concrete with targeted mechanical properties and simultaneously manage the consumption of waste materials.The ANN combined with particle swarm optimization algorithm provided satisfactorily results to estimate the residual CS of modified rubberized concrete after immersion in MgSOThis study investigated the performance of several modified rubberized concretes by exposing them to aggressive environments i.e., acid, and sulphate attacks, elevated temperatures. To examine the effect of WRTCs aggregate content and size on mechanical properties and structural morphology, four batches  were developed as high-performance, sustainable concrete. By using the available experimental test database, an ANN model combined by particle swarm optimization algorithm was presented to estimate the residual CS of modified rubberized concrete after immersion in MgSO