The alkali-activated cementitious material was prepared by partially replacing slag with recycled concrete powder (RCP). The influence of RCP substitution rates  on the performance of alkali-activated slag-RCP-based (AASR) foamed concrete was studied. The fluidity, water absorption, softening coefficient, compressive strength, flexural strength, drying shrinkage, thermal conductivity, and frost resistance of AASR foamed concrete were studied. The results show that the fluidity and softening coefficient of AASR foamed concrete decreases with the increase in RCP content, and the fluidity range is 230–270 mm. Due to the porous structure of the RCP, the water absorption of AASR increases. With the increase in the curing age, the strength of AASR foamed concrete increases. The addition of RCP reduced the mechanical properties of AASR foamed concrete. Compared with the control group, the compressive strength of AASR50 decreased by 66.7% at 28 days, and the flexural strength decreased by 61.5%. However, the 28 d compressive strength of AASR foamed concrete under all RCP replacement rates still meets the standard value (0.6 MPa). The addition of RCP effectively reduces the thermal conductivity of the AASR foamed concrete, and when the RCP content is 50%, the thermal conductivity is lowest, 0.119 W/(m·K); the drying shrinkage of the AASR foamed concrete can be improved by adding RCP, and the drying shrinkage value is lowest when the RCP is 30%, which is 14.7% lower than that of the control group. The frost resistance of AASR foamed concrete decreases with the increase in the RCP content. When the recycled micropowder content is 20–50% and after 25 freeze–thaw cycles, AASR foamed concrete has reached freeze–thaw damage. Foamed concrete is a kind of lightweight inorganic material, which has a wide range of application scenarios and can be used as filling materials, insulation boards, lightweight partitions, etc. . Compare3 prepared by Mastali et al. [3 was between 50.1 and 52.6%, with good durability. However, despite China producing over 100 million tons of slag annually, the market demand is high, and slag prices have been rising, and the continued high demand may limit future slag supplies [Alkali-activated slag-foamed concrete emerged to solve this issue. Since it does not need cement in the production process, it is a low-carbon and environmentally friendly material, with the advantages of high early strength and good water resistance ,10,11. Ti et al.  is 25–13i et al.  showed tsupplies . TherefoWith the acceleration of urbanization, massive construction waste, mainly concrete, has been produced. How to deal with these wastes has become an important issue for the sustainable development of buildings. Nowadays, many enterprises and scholars use crushed construction waste to produce aggregates ,20,21,22In this experimental scheme, AASR foamed concrete was prepared by adding RCP with different contents  to replace part of the slag, and the fluidity, water absorption, softening coefficient, compressive strength, flexural strength, drying shrinkage, and frost resistance of the AASR foamed concrete are explored. The results of this study contribute to expanding the application range of RCP and promoting the development of green cementitious materials.2/kg and a density of 2780 kg/m3. The raw material for RCP is obtained from waste concrete collected during the demolition process of a reinforced concrete building in Ningxia. After crushing the waste concrete, it is preliminarily screened through a 1.18 mm square hole sieve, and the obtained material is ground into micropowder using a planetary mill. The chemical composition of slag and RCP is shown in The cementitious materials used in this study are slag and RCP. The slag is selected as S95 grade slag, with a specific surface area of 524 mThe alkaline activator is made by mixing water glass and industrial flake sodium hydroxide with an initial modulus of 3.3. The foaming agent is a Legao foaming agent produced by Shandong Lego Company, mixed with tap water in a mass ratio of 1:50.3 was prepared by using RCP and slag as precursors. The water-binder ratio of foamed concrete is 0.34, the modulus of the activator is 1.0, and the alkali equivalent is 5%. RCP is used as a supplementary cementitious material to replace 10%, 20%, 30%, 40%, and 50% of the slag. Additionally, the specific mix design is shown in At the beginning of the test, it was determined that the AASR foamed concrete with a target dry density of 500 kg/mFirst, the slag and RCP are evenly mixed in a mixer. Then, water and an alkali activator are poured into the mixer and stirred for three minutes to obtain a slurry with uniform flow. Next, the prepared foamed mix is added to the slurry quickly and evenly. This is subsequently poured into the mold after mixing uniformly, wrapped with a plastic film, and placed in a standard curing room. This can be demolded after 24 h. Next, the demolded test block must be cured until the measurement age.According to standards ,31,32, tv is the ultrasonic wave velocity of the material; and r is the relative dynamic elastic modulus of the specimen; Vn is the ultrasonic wave velocity of the specimen after n freeze–thaw cycles; and V0 is the initial wave velocity of the specimen before the freeze–thaw cycle.Ultrasonic testing is an effective non-destructive testing method. The HU-U81 concrete ultrasonic detector was used to measure the wave velocity of the AARS foamed concrete before and after freezing and thawing, as shown in aterials ,35, the The fluidity results of the AASR foamed concrete under different RCP replacement rates are shown in The softening coefficient is an important parameter for the water resistance properties of materials. It can be seen from The influence of the RCP content on the flexural strength of the alkali-activated foamed concrete is shown in tf) and flexural strength (ff) of the foamed concrete is complex, which is affected by the composition, density, pore structure, curing conditions, and curing age of the foamed concrete. Generally, there is a positive correlation between the compressive strength and the flexural strength of the foamed concrete. According to the test results, the relationship between the AASR foamed concrete flexural strength and the cube compressive strength is shown in The relationship between the compressive strength (2 = 0.958) have good agreements with the experimental outcomes.It should be stated that the proposed equations with high accuracy ; at this time, the water content of the specimen is largely lost under the dry environment and internal hydration, and the nanopores in the AASR foamed concrete lose water seriously and the gel begins to densify. The combined effects of the two led to the sharp shrinkage of the specimen volume [−6 m, respectively, and the drying shrinkage performance of the AASR foamed concrete is the best under the 30% replacement rate of RCP. This is because as the substitution rate of RCP for mineral powder increases, the activity of RCP is low, the hydration reaction is slow, and the hydration products produced by hydration are reduced, resulting in smaller shrinkage [The drying shrinkage values of the AASR foamed concrete with different RCP contents are shown in n volume ; in addihrinkage . In the The mass loss rate is one of the important indicators reflecting the frost resistance of cement-based materials. 3. The main conclusions are as follows:(1)The fluidity and softening coefficient of the AASR foamed concrete decrease with the increase in the RCP content and its fluidity ranges from 230 mm to 270 mm. Due to the porous structure of the RCP, the water absorption of the AASR foamed concrete increased.(2)With the increase in the curing age, the strength of the AASR foamed concrete increases. The addition of RCP reduces the mechanical properties of the AASR foamed concrete; in particular, the larger the amount of RCP, the more obvious the downward trend. Although the addition of RCP reduces the compressive strength of the AASR foamed concrete, the 28 d compressive strength of the AASR foamed concrete under all RCP replacement rates still meets the standard value (0.6 MPa). According to the test results, this paper establishes a linear relationship between the compressive strength and flexural strength of the AASR foamed concrete under different RCP replacement rates, and the two have a high correlation.(3)The addition of RCP effectively reduced the thermal conductivity of the AASR foamed concrete, and when the RCP content was 50%, the thermal conductivity was the lowest, 0.119 W/(m·K); this is because RCP has irregular particles and high-water absorption capacity compared with slag, which will cause damage to the slurry foamed liquid film, leading to the increase in the irregular large holes in the specimen and the decrease in the hole wall compactness. With the increase in the RCP replacement rate, the porosity of the AASR foamed concrete increases, which is more obvious. At this point, due to the reduction in the slag, the hydration products decrease, the proportion of stable internal and external solid structures decreases, the efficiency of heat conduction decreases, and the thermal conductivity decreases.(4)The drying shrinkage of AASG foamed concrete can be improved by adding RCP, and the 28 d drying shrinkage value is the lowest when the amount of RCP is 30%, which is 15.6% lower than that of the control group. However, the drying shrinkage of AASR foamed concrete will increase slightly when the amount of RCP is too high, but it is still lower than the reference group; the frost resistance of the AASR foamed concrete decreases with the increase in the RCP content. When the recycled micropowder content exceeds 20%, after 25 freeze–thaw cycles, the mass damage rate of the AASR foamed concrete exceeds 5%, and the relative dynamic modulus of elasticity exceeds 60%, all of which have reached destruction.In this study, RCP and slag are used as the main cementitious materials to prepare AASR foamed concrete with a density of 500 kg/mThis study primarily focused on the influence of the RCP replacement rate on the fluidity, water absorption, softening coefficient, compressive strength, flexural strength, thermal conductivity, drying shrinkage, and frost resistance of AASR foamed concrete. However, high-temperature resistance, carbonation, sulfate attack, and durability are also important factors affecting the performance of foamed concrete. Therefore, in future research, exploring the durability of AASR foamed concrete is necessary. Moreover, additional research is needed to improve the mechanical properties of the concrete due to the addition of RCP by utilizing fibers or nanomaterials.


The aim of this study was to describe the time series of broad-spectrum antibiotic utilisation and incidence of antibiotic-resistant organisms during the implementation of antimicrobial stewardship programmes (ASP) in Singapore.An observational study was conducted using data from 2011 to 2020 in seven acute-care public hospitals. We applied joinpoint regressions to investigate changes in antibiotic utilisation rate and incidence density of antibiotic-resistant organisms.E. coli and K. pneumoniae decreased significantly in later periods, from H2 of 2016 to H2 of 2020 (HPC − 2.5%) and H1 of 2012 to H2 of 2015 (HPC − 4.6%) respectively. Anti-pseudomonal antibiotics with one joinpoint decreased significantly from H1 of 2011 to H2 of 2014 (HPC − 4.5%) and H2 of 2014 to H2 of 2020 (HPC − 0.8%) and that of quinolones with one joinpoint at H1 of 2015 decreased significantly in the first period. C. difficile with one joinpoint increased significantly from H1 of 2011 to H1 of 2015 (HPC 3.9%) and decreased significantly from H1 of 2015 to H2 of 2020 (HPC − 4.9%).Across the seven hospitals, quarterly broad-spectrum antibiotic utilisation rate remained stable. Half-yearly incidence density of antibiotic-resistant organisms with two joinpoints at first half (H1) of 2012 and second half (H2) of 2014 decreased significantly in the second and third period with a half-yearly percentage change (HPC) of -2.9% and − 0.5%, respectively. Across the five hospitals with complete data, half-yearly broad-spectrum antibiotic utilisation rate with one joinpoint decreased significantly from H1 of 2011 to H2 of 2018 (HPC − 4.0%) and H2 of 2018 to H2 2020 (HPC − 0.5%). Incidence density of antibiotic-resistant organisms decreased significantly in the two joinpoint periods from H1 of 2012 to H2 of 2014 (HPC − 2.7%) and H2 of 2014 to H2 of 2020 (HPC − 1.0%). Ceftriaxone with one joinpoint decreased significantly from H1 of 2011 to H1 of 2014 (HPC − 6.0%) and H1 of 2014 to H2 of 2020 (HPC − 1.8%) and ceftriaxone-resistant In the five hospitals with complete data, decrease in broad-spectrum antibiotic utilisation rate was followed by decrease in incidence density of antibiotic-resistant organisms. ASP should continue to be nationally funded as a key measure to combat antimicrobial resistance in acute care hospitals.The online version contains supplementary material available at 10.1186/s13756-023-01289-x. Antimicrobial resistance (AMR) can be described as a tragedy of the commons that requires participation from a wide range of stakeholders and multiple levels of governance . GloballIn the ensuing years, studies from various public hospitals demonstrated that ASP improved the appropriateness of antibiotic prescribing and reduced the duration of antibiotic use without compromising patient safety –13. ReduA 10-year observational study was conducted on broad-spectrum antibiotic utilisation and resistance data collected from seven public acute care hospitals in Singapore from 1 to 2011 to 31 December 2020. These acute care hospitals have different casemix and specialist services, ranging from a women’s and children’s hospital to hospitals with burns units, oncology and transplant services. In each hospital, antibiotic utilisation data was extracted from its pharmacy dispensing database and antibiotic resistance data extracted from its electronic laboratory reporting system. Broad-spectrum antibiotic utilisation data was submitted to the secretariat of the National Antimicrobial Resistance Control Committee (NARCC) on a quarterly basis and antibiotic resistance data on a half-yearly basis. In this study, we reported the initial list of antibiotics under NARCC surveillance and additional antibiotics added subsequently were excluded from our analysis. The broad-spectrum antibiotics included in the analysis were ceftazidime, ceftriaxone, cefepime, doripenem, ertapenem, imipenem, meropenem, intravenous (IV) amoxicillin-clavulanate, piperacillin-tazobactam, IV and oral (PO) ciprofloxacin, IV and PO levofloxacin, IV and PO moxifloxacin, colistin, polymyxin B, tigecycline, IV and PO linezolid, daptomycin and vancomycin.With national ASP funding from 2011, the multi-disciplinary ASP teams of each hospital developed and disseminated antibiotic guidelines for the empiric treatment of common infections and surgical antibiotic prophylaxis. These were based on international guidelines and the antibiogram of each hospital. Prospective review and feedback (PRF) of inpatient antibiotic use targeting mainly carbapenems and piperacillin-tazobactam was conducted by each hospital based on these guidelines. Depending on the specific needs of each hospital, PRF was also conducted for cefepime, vancomycin, IV and PO ciprofloxacin and IV levofloxacin. A computerised decision support system was used in one hospital in 2011 and this increased to a total of four hospitals by the end of 2015 . From 20A. baumannii was defined as concurrent resistance to imipenem or meropenem, ciprofloxacin and amikacin. The World Health Organization (WHO) anatomical therapeutic chemical defined daily dose (ATC/DDD) index was used. The DDDs of meropenem, cefepime, colistin and IV ciprofloxacin were updated from 2 to 3 g, 2 to 4 g, 3 to 9 million units, and 0.5 to 0.8 g respectively in 2019 [Antibiotic utilisation was measured in defined daily doses (DDDs) per 1,000 inpatient-days while the incidence density of antibiotic-resistant organisms was reported as the number of clinical isolates per 1,000 inpatient-days. Isolates of the same organism from the same patient within a six-month period were counted only once. Multi-drug resistant (MDR)  in 2019 . Antibio in 2019 –13. We dWe did not use interrupted time series analysis for this study as there were no pre-implementation data for comparison and the ASP activities of each hospital were not implemented at the same time. Hence, we used joinpoint regression models to identify the time points at which significant changes in rates of antibiotic utilisation and incidence density of antibiotic-resistant organisms occurred during the study period, which are also known as change points (“joinpoints”). We allowed up to five joinpoints for model fitting using the grid search method. A series of Monte Carlo permutation tests were used to select the optimal number of joinpoints, with Bonferroni correction for multiple testing.Once the optimal joinpoints were identified, the time series was divided into distinct segments between each pair of consecutive joinpoints. Using a natural log-linear model within each segment, the size of the change was estimated as a constant percentage change over time, which was quarterly percentage change (QPC) for utilisation rate of antibiotics and half-yearly percentage change (HPC) for incidence density of antibiotic-resistant organisms. Assuming constant variance and correlated errors, we conducted a weighted least squares analysis in which the first-order autocorrelation parameter was estimated from the data . The avep values reported were 2-sided and statistical significance was taken as p < 0.05. The joinpoint regression analyses were performed using the Joinpoint Trend Analysis software from the Surveillance Research Programme of the National Cancer Institute Version 4.9.1.0  [All ute, US) . The figThe total number of inpatient-days from 2011 to 2020 for the seven acute care hospitals was 22,073,764. The two hospitals with incomplete data contributed 3,401,994 (15%) of the total inpatient-days. During this period, 87,010 ASP interventions were made across the seven hospitals with 65,551 (75.3%) accepted. Acceptance rate increased from 70.4% in first half (H1) of 2011 to 82.0% in second half (H2) of 2020; AHPC was 0.9% . There were four joinpoints identified with significant increases in the third period  and fourth period .Overall quarterly rate of broad-spectrum antibiotic utilisation, excluding PO ciprofloxacin, IV and PO levofloxacin, and IV and PO moxifloxacin, remained stable across the seven hospitals during the study period with AQPC of -0.1%, 95% CI -0.2- to 0.01% Table . In Q1 oThe decrease in utilisation third-generation cephalosporins was mainly driven by ceftriaxone while the decrease in utilisation of carbapenems was primarily attributed to imipenem. Three joinpoints were detected for IV ciprofloxacin, and the only significant change in trend was in the first period from Q1 of 2011 to Q3 of 2016 with a QPC of-2.0%. The utilisation rate of IV beta-lactam/beta-lactamase inhibitors showed an increasing trend. Utilisation rate of IV amoxicillin-clavulanate significantly increased with a AQPC of 1.5%, from 40.1 to 62.0 DDDs/1,000 inpatient-days. There was one joinpoint at Q1 of 2013 for piperacillin-tazobactam with two periods of significant increase with the increase steeper in the first period: QPC of 3.8% vs. 0.5%. There was a significant decrease in the last joinpoint period for colistin (Q3 of 2015 to Q4 of 2020) and the last two joinpoint periods for polymyxin B (Q2 of 2013 to Q3 of 2019 and Q3 of 2019 to Q4 of 2020). Utilisation of ceftazidime (Q3 of 2013 to Q4 of 2020), piperacillin-tazobactam (Q1 of 2013 to Q4 of 2020), IV and PO linezolid (Q2 of 2018 to Q4 of 2020), daptomycin (Q3 of 2014 to Q4 of 2020) and vancomycin (Q2 of 2017 to Q4 of 2020) significantly increased in their last joinpoint period Table .A separate analysis of five acute care hospitals was conducted after excluding the two hospitals with incomplete data. Overall broad-spectrum antibiotic utilisation across the five acute care hospitals declined from 714.6 DDDs/1000 inpatient-days in Q1 of 2011 to 509.6 in Q4 of 2020 with AQPC of -0.8%, 95% CI -1.3 to -0.4% Table . In Q1 oUtilisation rate of anti-pseudomonal antibiotics  decreased significantly in the second joinpoint period (Q4 of 2012 to Q4 of 2013) and third period (Q4 of 2013 to Q4 of 2020). The decrease in third-generation cephalosporins was mainly driven by ceftriaxone while the decrease in carbapenems  was mainly driven by imipenem. The decrease in quinolones was mainly driven by PO ciprofloxacin Table .Utilisation rate of IV beta-lactam/beta-lactamase inhibitors increased significantly in the first joinpoint period (Q1 of 2011 to Q2 of 2014) and third period (Q4 of 2016 to Q3 of 2018). IV amoxicillin-clavulanate increased significantly in the second  and fourth joinpoint periods . There was one joinpoint at Q1 of 2013 for piperacillin-tazobactam with two periods of significant increase with the increase steeper in the first period from Q1 of 2011 to Q1 of 2013: QPC of 3.7% vs. Q1 of 2013 to Q4 of 2020, QPC of 0.3%. Both colistin and polymyxin B decreased significantly in their last periods. Piperacillin-tazobactam, PO and IV linezolid, and daptomycin increased significantly during their last periods Table .S. aureus (MRSA), a significant decrease in antibiotic-resistant organisms was still observed in the second joinpoint period from H1 of 2012 to H2 of 2014. Ciprofloxacin-resistant E. coli had the highest half-yearly incidence density, followed by ceftriaxone-resistant E. coli, ciprofloxacin-resistant K. pneumoniae and ceftriaxone-resistant K. pneumoniae.Overall incidence density of antibiotic-resistant organisms decrease significantly in the second  and third period  respectively. After excluding methicillin-resistant E. coli and K. pneumoniae decreased significantly in the last periods. Ciprofloxacin-resistant E. coli had one joinpoint at H2 of 2018 and increased significantly in the two periods with the increase steeper in the second period; HPC of 0.5% vs. 3.8%, while ciprofloxacin-resistant K. pneumoniae had three joinpoints and decreased significantly in the second period and increased significantly in the fourth period; HPC of -5.5% vs. 3.5%. Imipenem or meropenem-resistant E. coli and K. pneumoniae increased significantly with AHPC of 4.0% and 3.3%, respectively  and decreased significantly in the second period (HPC of -4.2%) (Table Incidence density of imipenem or meropenem-resistant %) Table .We compared significant changes in broad-spectrum antibiotic utilisation rate with that of the incidence density of antibiotic-resistant organisms in half-yearly periods based on the five-hospital analyses Tables  and 2. TE. coli and K. pneumoniae decreased significantly in later periods .5. PRF provided patient and prescriber level stewardship while computerised decision support systems and educational campaigns increased awareness of institutional antibiotic guidelines and built the culture of judicious antibiotic use. Annual reports were disseminated by NARCC to the respective hospital management based on data submitted as a form of benchmarking. This not only validated the national antibiotic stewardship programme but helped to engage hospital leadership for continuing support. Although we were unable to attribute these activities to the changes in antibiotic utilisation in our study, these activities could have contributed to the trends observed [Institutional guidelines encouraged the empiric use of antibiotics based on local hospital antibiogram sand international guidelines while expert practice usually relies on a few “work-horse” antibiotics which could explain the high initial utilisation rate of ceftriaxone and PO ciprofloxacinobserved –11, 19.E. coli and K. pneumoniae. It was previously reported that there was a positive association between increased use of ceftriaxone and the increase in extended-spectrum beta-lactamases that confer ceftriaxone resistance [C. difficile. In a local study, utilisation rate of broad-spectrum antibiotics had a significant negative correlation with incidence density of C. difficile and carbapenem-resistant P. aeruginosa but not with carbapenem-resistant A. baumannii [A. baumannii in our current study could be due to infection control practices but ASP remains important in controlling the incidence of these MDRO, including C. difficile [E. coli and K. pneumoniae locally could have affected the overall incidence density of ceftriaxone-resistant E. coli and K. pneumoniae [Enterobacterales locally was previously reported [Antibiotic use creates a selective pressure towards the emergence of antibiotic resistance. In the five-hospital analysis based on half-yearly interval, the decrease in utilisation rate of broad-spectrum antibiotics preceded the decrease in incidence density of antibiotic-resistant organisms. The decrease in utilisation of ceftriaxone preceded the decrease in incidence density of ceftriaxone-resistant sistance . The decaumannii . The sigifficile –24. The eumoniae –27. The reported .There are a few limitations in our study. As the reporting intervals of antibiotic utilisation and incidence density of antibiotic-resistant organisms to NARCC were different, we converted the quarterly time series of antibiotic utilisation rate to half-yearly intervals for comparison. We were unable to report on all antibiotics and hence may not be able to address “balloon effects” adequately. Nonetheless, we reported on antibiotics that were commonly regarded as broad-spectrum and those from the WHO watch list as they were regarded as targets of ASP monitoring . We coulThe work to ensure judicious use of antibiotics at our local hospitals where there is high antibiotic resistance is ongoing . The firOur study demonstrated reductions in the use of several types of antibiotics after nationally funded AMR surveillance and ASP were implemented, which were followed by reductions in antimicrobial resistance across several classes. Although there were increases in some classes of antimicrobial resistance and utilisation of some types of antibiotics, these findings suggest that ASP should continue to be funded nationally as a key measure to combat antimicrobial resistance in acute care hospitals.Below is the link to the electronic supplementary material.Supplementary Material 1


Antimicrobial stewardship (AS) programs aim to slow the growing threat of antimicrobial resistance. The majority of antibiotic prescribing occurs in outpatient settings. This study examines the effect of an AS intervention bundle on the proportion of inappropriate antibiotic prescriptions given to adult patients with bronchitis in outpatient settings of a large healthcare system.The Institutional Review Board approved this retrospective study of antibiotic prescription rates for adults (≥18 years old) diagnosed with bronchitis (identified using ICD-10 codes J20.9 or J20.8) during 2020 and 2021 in outpatient settings. An AS intervention bundle involving training and auditing of physicians’ antibiotic prescribing habits was enacted in January of 2021. A total of 8,176 encounters were reviewed for appropriateness of antibiotic prescriptions. Instances where no antibiotics were prescribed or antibiotics were prescribed for a comorbid condition were considered appropriate. Percentages of inappropriate antibiotic prescribing pre- and post-intervention were then compared via Chi-square analysis using SAS Enterprise Guide version 7.15 software.The proportion of inappropriate antibiotic prescribing for bronchitis decreased significantly from 44.9% pre-intervention to 32.5% post-intervention (p< 0.0001). Comparison of inappropriate prescribing rates by month showed significant decreases between the pre- and post-intervention periods in March , October , and November .AS activities can decrease inappropriate antibiotic prescribing for bronchitis in outpatient settings. Further analyses on site-specific, seasonal and demographic differences on the effect of our AS intervention bundle may further enlighten on how programs can decrease unnecessary antibiotic use for respiratory tract infections.All Authors: No reported disclosures


The lightweight concrete can meet the requirements of high strength (12.67 MPa) and low density (0.953 g/cm3). In addition, the addition of basalt fiber (BF) can effectively improve the compressive strength of the material without changing the density of the material. From a micro-level perspective, HC-R-EMS is closely combined with the cement matrix, which is conducive to increasing the compressive strength of concrete. Basalt fibers connect the matrix into a network, improving the maximum limit force of the concrete.Lightweight concrete is one of the effective means to solve the problems of structural component weight, energy efficiency, and fire safety in modern civil engineering. Heavy calcium carbonate-reinforced epoxy composite spheres (HC-R-EMS) were prepared by the ball milling method, and HC-R-EMS, cement, and hollow glass microspheres (HGMS) were mixed into the mold by the molding method to prepare composite lightweight concrete. The relationship between the HC-R-EMS volumetric fraction, the initial inner diameter of the HC-R-EMS, the number of layers of HC-R-EMS, the HGMS volume ratio, the basalt fiber length and content, and the multi-phase composite lightweight concrete density and compressive strength was studied. The experimental results show that the density of the lightweight concrete ranges between 0.953–1.679 g/cm Modern civil engineering  continuoLightweight concrete is used in the construction industry  to make Lightweight concrete can be made by introducing foaming agents into the concrete mixture  or by fi3. Using HGMS is environmentally friendly because they contain 45% recycled glass. The spherical shape and smooth surface of HGMS can be used to change the flowability of cement mortar and adding HGMS in lightweight concrete can promote fiber dispersion. Due to its low density, high compressive strength, and good dispersion and flowability, HGMS [Hollow glass microspheres (HGMS)  have devty, HGMS  are wide3. Early research on EPS [Expanded polystyrene (EPS) bead is a hard closed-cell foam plastic made by adding a foaming agent to polystyrene resin and heating it to soften, generating gas. Its density is less than 30 kg/mh on EPS ,36 concrh on EPS ,38 or ceh on EPS  concreteIn this experiment, HC-R-EMS was prepared by the ball rolling method ,41,42, u® LY 1564) and amine curing agent (Aradur ® 3486) were purchased from Huntsman Chemical Co., Ltd., Shanghai, China. The 42.5 Portland cement was purchased from Shenzhen Zhongning Technology Co., Ltd., Shenzhen, China. The Polystyrene foam balls (EPS) were purchased from Hangzhou Hangchao Packaging Materials Co., Ltd., Hangzhou, China. The K1 hollow glass bead (HGMS) was purchased from the 3M Company in Shanghai, China. The compressive strength of K1 is 1.72 MPa, the vacuum density is 0.125 g/cm3, and the particle size is 20–80 μm.Epoxy resin , the mass of the sample is measured. The length, width, and height parameters of the sample are measured using a digital caliper, and the volume is calculated. The average density of the sample is calculated using Formula (1).Compressive strength test: Use the universal testing machine  to test the compressive strength of HC-R-EMS lightweight concrete. This experiment is based on the Chinese standard GB/T16491-2008. The maximum test force can reach 300 kN and the maximum test range can reach 1100 mm.Surface morphology observation: To analyze the bonding issues at the surface of the composite materials, a scanning electron microscope (SEM)  is used to observe the surface morphology of the material. The sample is cut open to obtain an observation cross-sectional part, and an ultrasonic cleaner  is used to clean the surface dust of the material. Then, a sputtering coater (ISC150) is used to sputter a layer of gold on the surface of the sample in order to more clearly observe the morphological characteristics.This experiment focuses on the effect of different influencing factors on the performance of lightweight concrete. The influencing factors can be divided into the stacking volume fraction, diameter, and number of layers of the HC-R-EMS; the type of HGMS, the BF content, and length in the matrix. The specific formulations used for the experiments are shown in To avoid the occurrence of unexpected data and to reduce errors as much as possible, 50 HC-R-EMS samples were randomly selected for each group and the diameter and mass of the samples were statistically analyzed. The results show that the more layers of HC-R-EMS on the EPS, the higher the density of the prepared cement/epoxy composite material; the larger the EPS diameter, the lower the density of the prepared HC-R-EMS.3 (diameter 9.43–10.29 mm); (b) the HC-R-EMS-2 layer 0.444–0.828 g/cm3 (diameter 10.13–11.16 mm); (c) the HC-R-EMS-3 layer 0.757–1.023 g/cm3 (diameter 11.05–12.14 mm), as shown in The macroscopic diameter of the HC-R-EMS increases, the thickness of the macroscopic layer increases, and the density of the macroscopic layer increases. When the initial diameter of the EPS small balls is within the range of 8–9 mm, the diameter distribution of the HC-R-EMS is between 9–12 mm. The density of the HC-R-EMS is mainly distributed in three areas: (a) the HC-R-EMS-1 layer, 0.212–0.565 g/cm3 (8–9 mm) and 0.485 g/cm3 (10–11 mm). The larger the EPS, the larger the diameter and the lower the density of the prepared HC-R-EMS. As the diameter of the EPS increases, the density of the prepared HC-R-EMS decreases, as shown in When the number of layers is the same (two layers), the densities of the prepared HC-R-EMS are 0.641 g/cm3 (0%), 1.599 g/cm3 (20%), 1.480 g/cm3 (40%), 1.413 g/cm3 (60%), 1.321 g/cm3 (80%), and 1.280 g/cm3 (90%). Under different HC-R-EMS stacking ratio conditions, the compressive strengths of the composite materials are 72.1% (20%) of the pure HGMS-cement matrix strength; 69.6% (40%); 62.9% (60%); 50.6% (80%); 49.5% (90%).3, which is far lower than the density of the HGMS-cement-based system (1.679 g/cm3). As a result, the density of the concrete composite material decreases as the stacking ratio of the HC-R-EMS increases. When the stacking ratio of the HC-R-EMS is 90%, the density of the concrete composite material is only 1.280 g/cm3. Although the strength of the composite material is weakened to some extent, the minimum density of the concrete composite material (1.280 g/cm3) can minimize the weight of the material and achieve a lightweight effect.The density of the two-layer HC-R-EMS used in this experiment is 0.641 g/cmThe compressive strength of the concrete composite material is weakened as the stacking ratio of the HC-R-EMS increases. The main reason for this phenomenon is that the stacking volume fraction of the HC-R-EMS determines the number of holes in the concrete. As the filling amount of the balls increases, the possibility of the HC-R-EMS contacting each other in the HGMS-cement matrix increases. When the material is loaded, the contact points of the balls are easily damaged. In addition, the increase in the amount of HC-R-EMS filler makes it easy for the concrete composites to produce air bubbles in the preparation process and increases the interface defects of the materials, which obviously weakens the compressive strength of the concrete composites.3 (8–9 mm) and 1.122 g/cm3 (10–11 mm), respectively. The density of the lightweight concrete decreases with the increase in the HC-R-EMS inner diameter; this is because as the initial diameter of the EPS balls increases, the density of the HC-R-EMS decreases with its initial diameter. Thus, the density of the lightweight concrete made from HC-R-EMS with a larger inner diameter also decreases.3 (one layer), 1.205 g/cm3 (one layer), 1.280 g/cm3 (two layers), and 1.301 g/cm3 (three layers). From In order to study the effect of the reinforcement layers on the compressive strength of the multi-phase lightweight concrete, the present group of experiments used HC-R-EMS with an inner diameter of 8–9 mm, and the volume fraction of the HC-R-EMS added in the matrix was 90%. One, two, and three layers of reinforcement layers were selected, and the EPS control group was set. As shown in 3 (20% HGMS), 1.280 g/cm3 (40% HGMS), and 1.088 g/cm3 (60% HGMS), respectively. The compressive strength of the lightweight concrete filled with HC-R-EMS decreases with the increase in the HGMS ratio in the matrix. When the filling HGMS ratio is 20%, the strength of the lightweight concrete is the highest, which can reach 8.63 MPa; the compressive strength of the lightweight concrete filled with 40% and 60% HGMS are 99.1% (40%) and 62.2% (60%) of that filled with 20% HGMS, respectively. This is because HGMS is a kind of micro, hollow spherical powder with self-lubricating and non-water-absorbing characteristics. Due to the smooth surface of the HGMS and the insufficient bonding with the cement paste, the concrete with a large amount of HGMS material usually has low strength and brittle failure.In addition to the accumulation volume fraction, thickness. and inner diameter of the HC-R-EMS filled in concrete, the composition of the lightweight concrete matrix also affects the performance of the multi-phase composite lightweight concrete. In this group of experiments, an 8–9 mm diameter enhancement of two layers of the HC-R-EMS with a filling volume fraction of 90% was used. The matrix volume ratios of 20%, 40%, and 60% of K1 grade HGMS and cement mixed were selected as the matrix of the multi-phase composite lightweight concrete. In order to study the effect of the different lengths of basalt fibers on the compressive strength of the multi-phase composite lightweight concrete, this group of experiments used a 90% volume fraction of HC-R-EMS, where HC-R-EMS was reinforced with two layers of heavy calcium carbonate using 8–9 mm EPS, and the matrix was made of a mixture of 40% K1 and 60% cement. Then, 3 mm, 6 mm, 9 mm, and 12 mm basalt fibers were added to the matrix, with a mass fraction of 2.0%. Due to the reduction in the lightness and the ease of the concrete after fiber addition, the water-to-cement ratio was increased in the fiber-added lightweight concrete groups to facilitate the experiment.3, 1.256 g/cm3, 1.260 g/cm3, and 1.268 g/cm3, respectively. From the densities of the lightweight concrete blocks with four different lengths of basalt fibers, it can be seen that the longer the length of the added basalt fibers, the denser the lightweight concrete is, but the density change is not obvious.In order to study the effect of the different contents of BF on the compressive strength of the multi-phase composite lightweight concrete, this group of experiments used a 90% volume fraction of HC-R-EMS, in which HC-R-EMS was obtained by enhancing two layers of heavy calcium carbonate with 8–9 mm EPS. The matrix was mixed with HGMS and cement in a volume ratio of 2:3. Then, 0.5%, 1%, 1.5%, and 2% of 9 mm basalt fibers were added to the matrix, respectively. Due to the reduction in the lightweight concrete and plasticity after adding the fibers, this group of experiments increased the water-cement ratio during the preparation of the lightweight concrete to facilitate the experiment.3, 1.204 g/cm3, 1.205 g/cm3, 1.219 g/cm3, and 1.260 g/cm3, respectively.The density of the test group with BF was reduced due to the increase in the water to ash ratio and was lower than that of the lightweight concrete blocks without BF. Only the lightweight concrete blocks with a 2% mass fraction of BF had a higher compressive strength than the lightweight concrete blocks without the addition of BF.As the fiber content added to the lightweight concrete specimen increases, the density of the specimen increases. When the BF content is increased from 0.5% to 1% and from 1% to 1.5%, the density does not increase by more than 1%. Increasing the BF content from 1.5% to 2% increases the density by more than 3%. The addition of small amounts of BF does not increase the density of the lightweight concrete specimens too much, but when the BF content is increased, the increase in the density begins to become greater. This is because when the fibers content is increased, there are more fibers on the surface of the lightweight concrete specimen, the pore channels for water from the interior to the surface of the lightweight concrete are blocked, and the water loss and void ratio of the specimen are reduced, increasing the compressive strength of the specimen and the density at the same time.The greater the content of fibers in the specimen, the more the compressive strength of the lightweight concrete specimen increases and the greater the compressive strength of the specimen. When a light weight concrete specimen is added with a mass fraction of 2% BF, the compressive strength is greatest at this point. This is because when the number of fibers increases, the adhesion within the matrix increases, the matrix is tighter and the strength of the lightweight concrete specimen increases. The increase in the compressive strength of the lightweight concrete specimens was relatively most pronounced when the mass fraction of BF was 2.0%, with a 22.8% increase in the compressive strength compared to the lightweight concrete specimens without BF in the HGMS system. This is due to the ability of the fibers to fill the voids between the concrete, making it more compact.Due to the action of EPS and the “ball rolling” preparation process, the inner and outer surfaces of the reinforced epoxy composite spheres are well curved, and when the epoxy composite spheres are compressed by an external force, the external force is transmitted along the surface of the spheres. As shown in The purpose of adding fibers is to connect the matrix into a network, thereby increasing the maximum confining force of the matrix concrete. In this paper, basalt fibers were investigated, and the results show that the addition of basalt fibers does have a reinforcing effect on the compressive strength of lightweight concrete. This is mainly due to the basalt fibers having the effect of connecting adjacent epoxy composite balls. Damage to plain concrete blocks under external forces is sudden, brittle, and completely destructive, whereas the addition of basalt fibers inhibits the production of such sudden damage.The microstructure in In this paper, HC-R-EMS was prepared by the ball rolling method and filled into the matrix of the HGMS-cement system as an aggregate, and then basalt fibers were added to prepare a multiphase composite concrete material. The relationship between the stacking volume fraction of the HC-R-EMS, the initial internal diameter of the epoxy composite ball, the number of reinforcing layers of HC-R-EMS, the volume ratio of the HGMS, the length and content of basalt fibers, and the compressive properties of the composite lightweight concrete were investigated. The main findings are summarized below.(1)3 and 12.67 MPa, respectively, which were 57% lower in density and 73% lower in compressive strength compared to the concrete with 0 volume fraction of HC-R-EMS. Although the compressive strength was reduced, the concrete had the lowest density and the highest compressive strength compared to the other experimental groups under these conditions.The strength and density of the lightweight concrete specimens prepared by filling with HC-R-EMS are related to the volume fraction of the stacking of the HC-R-EMS, the initial inner diameter of the epoxy composite spheres, and the number of layers of reinforcement of the HC-R-EMS. The compressive strength and density of the lightweight concrete specimens were also reduced. The density and maximum compressive strength of the lightweight concrete at a 90% volume fraction of HC-R-EMS, 8–9 mm initial internal diameter, and three layers of HC-R-EMS reinforcement were 0.953 g/cm(2)As the volume proportion of the HGMS increases, the density and compressive strength of the multi-phase composite concrete decreases, and when the volume fraction of the HGMS is 60%, the overall density and compressive strength of the concrete decreases significantly due to the smooth surface of the HGMS and the lack of bonding with the cement paste.(3)The addition of basalt short-cut fibers to the concrete matrix can improve the strength of lightweight concrete specimens. With the increase in the fiber length and mass fraction, the strength of the lightweight concrete specimens will increase, but the addition of fibers will also reduce the ease of the concrete, increasing the difficulty of production and the need to increase the water-cement ratio at the same time. The higher the fiber content, the higher the density and strength; the longer the fiber length, the higher the density of the lightweight concrete specimens, but the increase is not significant, with the maximum strength occurring at 9 mm fiber length.In this work, the effect of an increase in fiber on the strength of lightweight concrete was investigated within a certain range, and the compressive properties of lightweight concrete became stronger with the increase in the basalt fiber content, but the threshold value of the fiber content was not explored, and further tests can be conducted in the future to investigate to what extent the increase in the fiber content will seriously affect the compressive strength of concrete. In addition, tensile strength and bending strength are also important indicators of concrete, which can be considered together in the future to evaluate the overall performance of concrete.


Twelve crossover studies were amenable for metanalysis. Coadministration of diuretics was associated with a mean 17% increase in plasma antibiotic AUC  and a mean decrease in antibiotic Vd by 11% . However, the half-life was not significantly different . The remaining 13 observational and population PK studies were heterogeneous in design and population, as well as prone to bias. No large trends were collectively observed in these studies. There is currently not enough evidence to support antibiotic dosing changes based on the presence or absence of loop diuretics alone. Further studies designed and powered to detect the effect of loop diuretics on antibiotic PK are warranted in applicable patient populations.Loop diuretics and antibiotics are commonly co-prescribed across many clinical care settings. Loop diuretics may alter antibiotic pharmacokinetics (PK) via several potential drug interactions. A systematic review of the literature was performed to investigate the impact of loop diuretics on antibiotic PK. The primary outcome metric was the ratio of means (ROM) of antibiotic PK parameters such as area under the curve (AUC) and volume of distribution (V Loop did) of antibiotics. Regarding antibiotic clearance (CL), loop diuretics may increase urine volume, as well as the amount of antibiotic excreted in the urine [Loop diuretics have several important physiologic effects that may alter the pharmacokinetics (PK) of antibiotics. For example, volume contraction as a result of diuretic therapy may lead to decreased volume of distribution , and the PRISMA 2020 checklist was used as a guide to perform, complete, and report the review. A total of 1300 titles were found across the databases, with 1125 available for screening after duplicates were removed. Two investigators (D.A.K. and D.J.S.) independently screened the titles and/or abstracts. Following this stage of review, 81 articles were identified that may have met inclusion criteria, of which 77 were retrieved. Two investigators (M.O.E. and R.J.N.) independently screened the 77 full articles for inclusion, and disagreements were resolved by a single author (D.J.S.), resulting in 25 studies included in this review. The full search strategy and PRISMA 2020 flow diagram are available in the last), volume of distribution (Vd), half-life (T1/2), maximum concentration (Cmax), amount excreted in urine (Ae), and eGFR of the antibiotic before and after loop diuretic co-administration. When available, these data were extracted manually. When not available, if time–concentration curves were reported, the data were digitized using WebPlotDigitizer .Data were collected by a single author (D.J.S.). Studies were categorized by design and are summarized in Pharmacokinetic analyses were limited to the crossover studies . The ratd and T1/2 are related by the following formula:d and Cmax are related for an IV bolus dose by the following formula:Pharmacokinetic parameters are algebraically related. For example, Vd and T1/2 were not calculated from available parameters as they would be a reflection and provide similar information to other reported PK parameters. In addition, the analysis of such calculated parameters may be biased toward those reported as it relies on the reported parameters. When only time–concentration curves were available, noncompartmental analysis (NCA) was used to calculate PK parameters using the digitized data. Phoenix WinNonLin  was used to perform NCA.Therefore, missing PK parameters such as Vd using Equation (2), variability was assumed to be 20% CV, which was generally consistent with the data reported in the crossover studies. The meta-analyses and forest plots were performed using the “metagen” and “forest.meta” functions, respectively, from the meta package (version 6.0), using a random effects model with the meta default presets and summary measure set to “ROM” for ratio of means [The ratio of mean PK parameters is a standard and informative way to present the effect of a covariate on PK parameters or the bioequivalence of a new formulation of a product compared to its reference product ,38. Therof means . In the crossover studies amenable for meta-analysis, no clear patterns emerged to elucidate heterogeneity. Aside from two studies in hospitalized patients, demographic variables were fairly uniform, spanning a relatively short range. Older age and lower weight found in hospitalized patients were confounded by hospital status, in addition to a higher risk of bias in studies in hospitalized patients due to a higher likelihood of carryover effects. Given these limitations, heterogeneity was primarily explored qualitatively and is described in the discussion. However, data were sufficient to explore subgroup analysis by antibiotic class and specific loop diuretic (furosemide vs. other diuretic). Missing data were excluded from the meta-analysis. No sensitivity analyses were performed because the nature of this meta-analysis was exploratory, and only very large effects on PK parameters require clinical dose changes .The risk of bias was assessed collaboratively by two authors (A.T.K. and J.P.D.) using the revised Cochrane risk-of-bias tool for randomized crossover trials (RoB 2) . The risThere were 12 unique crossover studies with 16 total study arms including 88 subjects . The mos1/2, Vd, Cmax, Ae, and eGFR are summarized in d, with 0% heterogeneity; however, again, only two individual studies achieved statistical significance. Half-life was largely unchanged in the presence of a loop diuretic, with no study demonstrating a significant effect, and with a mean non-statistically significant 6% increase. Given that AUC increased and Vd decreased in similar proportions, the finding of a nearly unchanged half-life is expected as T1/2 is mathematically determined by the ratio of CL and Vd, and CL is inversely proportional to AUC (see Equations (1) and (2)). An observed overall mean increase of 15% in Cmax was consistent with the observed decrease in Vd, as Cmax and Vd are inversely proportional (see Equation (3)). Presence of a loop diuretic was associated with a statistically significant 30% increase in Ae; however, heterogeneity was 90%, with a large prediction interval crossing one. There were insufficient data for subgroup analysis; however, there was no obvious trend suggesting that an antibiotic class or specific diuretic would explain the heterogeneity. Generally, presence of a loop diuretic was associated with a minimal effect on eGFR, i.e., an overall nonsignificant mean effect of a 4% reduction. However, Lawson et al. [Pooled effect estimates of loop diuretics on PK parameters AUC, Tn et al.  and Tilsn et al.  demonstrThe risk of bias for crossover studies is summarized in d from baseline day 1 to days 12–16 in the antibiotic vs. antibiotic + loop diuretic cohorts [1/2 were still found between the groups. Marlowe et al. performed a pediatric PK study, collecting antibiotic vancomycin samples in 36 patients and performing a linear regression analysis to explore the effect of total diuretic dose on PK parameters [d, there was no significant trend between total fluid balance and Vd. The reason for this is unclear and suggests that the effect of furosemide on vancomycin Vd in this study may have been biased. Hirai et al. [The five observational cohort studies included in this review are summarized in  cohorts . Neither cohorts . These srameters . Althougi et al.  demonstrIncluded in this review were eight population PK studies gathering data from a total of 2523 patients with an average of 9% (N = 228) receiving a loop diuretic ,34,35,36d, and minimal changes in antibiotic T1/2. Interestingly, there was also a trend toward a significantly increased antibiotic Ae of 30% . The observed increases in AUC and Ae may be partially explained by volume contraction. However, Vd does not mathematically affect AUC, and the decrease in Vd was only 11% on average, compared to a 30% increase in Ae on average. Therefore, we hypothesize that another physiologic process must also account for the increased AUC. One possible mechanism may be the reduction in active antibiotic secretion via OAT1 and OAT3 as a result of furosemide transporter inhibition. The observed increase in AUC is less likely explained by electrostatic interactions leading to greater passive reabsorption. Cephalosporins are generally known to be negatively or neutrally charged at physiologic pH [To our knowledge, this is the first systematic review and meta-analysis to assess the impact of loop diuretics on antibiotic pharmacokinetics. In crossover studies, we found that loop diuretics were consistently associated with moderate increases in antibiotic plasma AUC, decreases in antibiotic Vlogic pH , whereaslogic pH ,49. HoweAlthough the increase in AUC associated with loop diuretic use in the crossover studies was modest (mean 17%), no standard clinical antibiotic dose adjustments are recommended on the basis of this finding. The crossover studies mostly included healthy adults, greatly limiting the ability to extrapolate results to more common clinical scenarios. Furthermore, a 17% increase in AUC is not necessarily a large enough effect size to warrant standard antibiotic dose decreases, and there were insufficient data on repeat concomitant dosing to understand the PK of repeatedly dosed antibiotics with loop diuretics. Therefore, even for a generally healthy patient where the crossovers studies may apply, a standard antibiotic dose reduction is not warranted. For example, consider a case where an adult with normal kidney function is taking chronic loop diuretic therapy for venous insufficiency. If this patient developed a mild community-acquired pneumonia and required amoxicillin–clavulanate therapy, a 17% dose decrease used to account for the possible increase in AUC would result in a prescription of approximately 725 mg amoxicillin compared to 825 mg amoxicillin twice daily. Amoxicillin has a large therapeutic window, with mostly idiosyncratic adverse effects . TherefoThe observational cohort studies and population PK studies were very heterogeneous in design, population, and outcome measure. Of note, three of eight population PK studies found furosemide to have a statistically significant effect on antibiotic CL, with a reduction of 20–30%. However, many covariates are often tested when developing population PK models. This raises the possibility of a false positive due to multiplicity, especially given various other factors that could alter antibiotic PK in a hospital setting ,52. FurtFurther limitations of the results of this study include limited data on specific antibiotics and wide variations in how the loop diuretic was administered. For example, some authors tested the effect of loop diuretics administered orally 1–3 h prior to antibiotic administration, while others tested co-administration of intravenous loop diuretics with an antibiotic. The timing of loop diuretic dosing in relation to antibiotic dosing in the cohort studies and population PK studies was not commonly reported. Furosemide is known for highly variable oral bioavailability, especially in edematous states . Since tOverall, there appears to be a consistently observed increase in AUC for antibiotics associated with loop diuretic coadministration in healthy adults. This result should not be extrapolated to patient populations commonly receiving concomitant prescriptions of antibiotics and loop diuretics. There was not strong enough evidence from the observational cohort studies or population PK studies to recommend antibiotic dosing changes in corresponding patient populations. However, there remains a potential for loop diuretics to impact antibiotic PK, and further research is warranted to better characterize antibiotic PK when concomitantly prescribing a loop diuretic in applicable patient populations. Loop diuretics may alter antibiotic PK via different mechanisms depending on the underlying physiology. Further research should focus on specific patient populations that are narrowly defined to better isolate the effect of loop diuretics on antibiotic PK.


The present paper deals with the properties of hardened cement mixtures that have been exposed to microwave radiation. Microwaves fall under electromagnetic waves (EMW), and the main reason for using EMW radiation is to accelerate the drying of concrete as well as to reduce the time required to obtain the handling strength after it is removed from the mould. This paper is divided into two main parts. In the first part, three sets of cement samples were made. One set of samples solidified naturally in air and the second and third sets of samples were exposed to EMW radiation, with different exposure times for each. The solidification was then stopped, and the representation of the major minerals was experimentally determined. The second part of the experiment focuses on the properties of the hardened cement mixtures, both in terms of strength and physical properties. The experiment was carried out on two sets of samples. Each mixture was exposed to EMW radiation, the main differences being the exposure time and the position of the samples relative to the EMW generator. The aim of the experiments is to determine the resulting mechanical properties of the samples in comparison with those that were subjected to normal solidification in air. The data from these experiments suggest that microwave radiation can be used to accelerate the curing of concrete specimens, obtaining the handling strength in a relatively short time, but a reduction in the resulting strength can be expected compared to the reference specimens. Concrete is the most widely used building material in the world, with production increasing every year . There aCurrently, there is a growing demand for precast concrete units . They arMicrowaves are part of electromagnetic waves (EMW), and one of the possible usages of microwave radiation in construction practice may be in the curing of concrete, specifically, accelerating the setting of concrete in its initial stages and gaining handling strength. This would provide the opportunity to remove the concrete blocks from the moulds faster and ensure a higher production rate. Pilot studies were already carried out in 2002. They were undertaken by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), an Australian company led by Dr Swee Liang Mak who dubbed the research Low Energy Accelerated Processing (LEAP). The result of this pilot research was that microwave radiation can be used to accelerate the setting of concrete, and the difference in strengths between reference concrete samples and concrete samples where accelerated setting had taken place was within 10% after 28 days, and after 4 h and 30 min, a strength of about four times that of the reference samples was even achieved at a water factor of 0.5 .The presented research builds on the initial, previous research and extends it further, in particular by analyzing the effect of microwave radiation on C-S-H gels during concrete setting and subsequently on the properties of the hardened concrete. The distribution of individual minerals is investigated by X-ray analysis and their structure is studied by microscopy. Furthermore, the results of the previous experiments are methodically verified by checking the strength and absorption characteristics.The main purpose of this work is to verify the possibility of using microwave radiation in the hardening of concrete. The reason for this experiment is the desire to speed up the hardening process in order to reduce the amount of time the products have to be stored in moulds before they gain handling strength. By speeding up the curing and obtaining the handling strength earlier, this would ensure higher concrete production.Efforts have been made in the past to speed up the curing of concrete and there are a number of ways to speed up the process. However, the resulting concrete properties vary considerably from reference values, with standard concrete strengths being 20% lower where the microwave acceleration of curing has taken place, which can be seen in Researchers ,13 have Kjellsen and Detwiler  report tLothenbach et al.  state thNamarak et al.  indicateSince cement is the binder component of concrete, this paper investigates and verifies the effect of microwave radiation on it, or more precisely, on C-S-H gel.2 to 10 W/m2) [Microwaves refer to a portion of electromagnetic radiation with a frequency of 300 MHz to 300 GHz, corresponding to wavelengths from 1 mm to 1 m. More frequencies are allowed for industrial use, but in civil engineering the frequency of 2450 MHz with a wavelength of 12.2 cm is of particular interest. The microwave radiation causes heating, and the molecules become oriented according to their polarity in the electric field. When microwave radiation comes into contact with water molecules, electromagnetic energy is transformed, and the molecules are heated. Subsequently, other construction materials are heated . Strong 10 W/m2) .Almost every household has a microwave oven nowadays, and the concept of microwave heating is also used in many other sectors outside the food industry. For example, it is widely used in medicine, the aforementioned food industry, the military or aviation industry, as well as in the construction industry. Numerous studies have already been carried out in the field of construction, which have confirmed the possibility of using microwaves for drying construction materials ,29,30,31The resulting properties can be seen in In For two samples, the curing process was stopped after 60 min. One sample was exposed to microwave radiation and the other cured in the standard way. X-ray analysis was performed on these samples and the resulting radiographs can be seen in When comparing the fresh concrete bulk density values, the results do not show significant differences. The bulk density of hardened concrete was determined at the age of the samples of 7, 14, and 28 days. This test was carried out according to ČSN EN 12390-7 on 40 × 40 × 160 mm beams and it preceded the compression test. The test specimens were stored in a water bath prior to the test. The results and corresponding time histories of the bulk weights of all concretes are shown in the graph in The tensile strength test was carried out according to ČSN EN 12390-5 on beams of 40 × 40 × 160 mm, and it preceded the compression test. The test specimens were stored in a water bath before the test and then dried in an oven at 105 °C. The tensile strengths of each specimen over time for all concretes are shown in the graph in The compressive strength test was carried out according to ČSN EN 12390-5 on 40 × 40 × 160 mm beam fragments and was completed after the tensile strength test. The test specimens were stored in a water bath prior to the test and then dried in an oven at 105 °C. The compressive strength of each specimen over time for all concretes is shown in The absorption test was carried out according to ČSN EN 12390-5 on beams of 40 × 40 × 160 mm and preceded the tensile test. Prior to the test, the specimens were stored in a water bath and then dried in an oven at 105 °C, after which they were weighed and placed in a water bath for 24 h and weighed again. The values of water absorption of each sample over time are shown in 2-Al2O3, Fe2O3, without significant representation of minor components. The analysis only captures the presence of crystalline phases, because glassy phases cannot be captured by this X-ray diffraction method.It is evident from the radiographs taken that the used cements were silicate cements based on Portland clinker, of the system CaO-SiOIn the initial phase, the hydration process is influenced by the EMW stress, which causes an increase in the temperature of the water present around the cement grains, namely the hydration rate applied by the reaction kinetics on the surface of the cement grains. Crystals of ettringite and calcium hydroxide are precipitated from the supersaturated solution. It is apparent from the course of the radiographs that no unexpected crystalline phases are formed. It seems that the effect of EMW radiation affects the reaction kinetics of hydration mainly in its initial phase. A comparison of the individual radiographs from the experiment can be seen in The black curve represents the resulting radiograph of the reference sample after 30 min of hydration. The purple curve represents the resulting radiograph of the reference sample after 60 min of hydration. The blue curve represents the resulting radiograph of the sample that was exposed to microwave radiation for 30 min. The green curve represents the resulting radiograph of the sample that was exposed to microwave radiation for 60 min.The rate of hydration, together with the amount of hydration heat released, depends on a number of factors, but the determining influence is primarily the mineralogical composition of the cement. The rate of hydration depends on the time of mixing of the cement with water; later, it decreases with time. It is known that the ratio of alite to belite can influence the increase in strengths and the development of the heat of hydration at the various stages of hydration. The age of the cement stone and the value of the specific surface area of the cement grains can be also considered as factors influencing hydration, since the depth of hydration is small relative to the largest size of the clinker grains in coarse-ground cements, for example.Based on the conducted experiments and their subsequent evaluation, it was possible to confirm the effect of curing acceleration by microwave radiation on the mechanical properties of composite materials where cement is used as a binder. The data obtained show that microwave radiation can be used to accelerate the curing of concrete specimens, obtaining the handling strength in a relatively short time, but a reduction in the resulting strength can be expected compared to the reference specimens.The experiment was conducted in three sets. In the first set, the concrete specimens that were cured in a standard manner in air were used. In the second set, the concrete samples were exposed to microwave radiation for 30 min. In the third set, the concrete samples were exposed to microwave radiation for 60 min. The resulting values of mechanical and physical properties of the samples can be observed in The resulting mechanical properties were determined by destructive strength tests. The tensile strengths of the specimens exposed to microwave radiation and the reference specimens were found to be comparable. Therefore, the main difference in the mechanical properties is mainly in the compressive strength. The experiments show that the resulting compressive strengths of the reference specimens are higher than those of the specimens exposed to microwave radiation, and at the same time a trend can be observed whereby the resulting compressive strength of the concrete decreases as the time of exposure to microwave radiation increases. The results suggest that the cause of this difference can be found in the higher temperature to which the concrete was exposed. The values of bulk density and absorption can be considered comparable for all samples and, in general, the resulting effect of microwave exposure on these properties of the samples cannot be clearly specified.X-ray analysis indicated that the samples contain the same minerals in approximately equal proportions. In general, it cannot be said that microwave exposure has an effect on the representation of individual clinker minerals during hydration of the C-S-H gel. The display of the specimens can be seen in The advantage of microwave heating in general is that the heating of the moisture contained in the porous system of the building material occurs directly in the material; this is accomplished through the absorption of microwave radiation by the moisture. With microwave heating, handling strength is achieved in a relatively short time and the process of producing concrete parts can be accelerated. Other advantages include that the microwave heating directly in the construction material is fast; that microwave drying can be applied to a wide range of building materials; and that microwave emitters are mobile and easy to operate.Disadvantages include, for example, that the cost of purchasing a microwave generator is higher; that microwave radiation can be harmful to health and it is therefore not advisable to be near the irradiated material; and that it is not possible to continuously measure the temperature in the irradiated material because the temperature sensors are metal based, so they interact with the microwave radiation.The experiments carried out can be considered as initial experiments and the paper is intended to serve as a stimulus for further research to address the current issue of prefabricated parts production and acceleration of their curing, for example, by reducing the water required for cement hydration.The experimental study was carried out on several concrete samples. For the sake of transparency and reproducibility of the individual experiments, the mixture that formed the final concrete was always the same. Specifically, the concrete was a mixture where the binder was Portland cement CEM I 42.5 R, and the filler was glass sand and water. The representation of the different components in the mixture was in the ratio 1:3:0.5.The main objective of the experiment was to investigate the effect of microwave radiation on fresh concrete during its setting and curing. A total of 48 samples of this mixture were made and placed in steel and silicone moulds with internal dimensions of 40 × 40 × 160 mm. A total of 24 samples were solidified and cured in a standard way in the steel moulds in air and 24 samples were exposed to microwave radiation.Of these 24 samples, 12 were exposed to microwave radiation for a total of 30 min and the other 12 samples were exposed to microwave radiation for 60 min. The samples were placed 30 cm away from the microwave generator as shown in the following These samples were further stored in a water bath for 7, 14, and 28 days and then subjected to strength tests, i.e., compressive and tensile strength, a water absorption test, and bulk density test.In addition, 6 samples of fresh mixtures were made and placed in circular containers with a diameter of 80 mm and a depth of 10 mm. Three of these samples were solidified and hardened in a standard way in air, whereas the other three samples were exposed to microwave radiation. These samples were stopped from solidifying after 30 min using alcohol and subjected to X-ray analysis. The aim was to determine the representation of the different clinker minerals in the mixtures and to find differences in solidification by the two methods.Currently, several types of EMW radiation are used in building practice for drying damp buildings. Although a lot of systems dry masonry by simply connecting an EMW generator to a magnetron, the use of EMW antennas increases the efficiency of drying. Typical drying methods in construction practice use a rod- or funnel-shaped EMW antenna . In the The individual components were portioned and mixed according to a fixed procedure. First the aggregate was dried, then the individual components were weighed to ensure that the concrete would have the same properties for all samples. The weighed components were dosed into the forced circulation mixer in the order of aggregate and then cement. This mixture was stirred for 90 s, which ensured a high homogeneity of the dry component. After the mixture was homogenized, the water was added. The fresh concrete was deposited into the moulds, which were wiped with a separating agent for easier demoulding. A total of two types of moulds with internal dimensions of 40 × 40 × 160 mm were used, namely a steel mould and a silicone mould. The compacting of the concrete was carried out by vibration—a vibrating shaker table was used for the three gang beam moulds. A total of 48 samples of this mixture were produced and placed in steel and silicone moulds with internal dimensions of 40 × 40 × 160 mm. A total of 24 samples were solidified and hardened in the standard way in the steel moulds in air and 24 samples were exposed to microwave radiation.Of these 24 samples, 12 were exposed to microwave radiation for a total of 30 min while the fresh mixture was solidifying, and the other 12 samples were exposed to microwave radiation for 60 min. The samples were placed 30 cm from the microwave radiation generator as shown in Demoulding of the specimens was always carried out within 24 h of placing the concrete in the moulds, and the specimens were legibly labeled and placed in the environments in which they were treated. One common treatment method was chosen for the concrete, placing the blocks in a water bath at 20 °C.In order to allow the comparison of the properties of the different concretes, the same test methods and procedures were chosen for all samples. The overall set of experimental work can be divided into two parts.The first part of the testing was aimed at determining the representation of clinker minerals in the concrete during setting. A total of 6 samples of fresh mixes were made and placed in circular containers with a diameter of 80 mm and a depth of 10 mm. Three of these samples were solidified and cured in a standard way in air and three samples were exposed to microwave radiation. These samples were stopped from solidifying after 30 min using alcohol and subjected to DTA analysis. The aim was to determine the representation of the different clinker minerals in the mixtures and to find differences in solidification between the two methods.The second part of the test methods concerns hardened concrete, more precisely the determination of the physical and mechanical properties of hardened concrete. The compressive strength of the concretes was determined on beams of dimensions 40 × 40 × 160 mm on fractions of the solids after the flexural tensile strength test.The basic treatment method was a water bath. The test specimens were carefully and legibly labeled after demoulding and then placed in a container of potable water that was placed in a tempered laboratory. The water was kept at a constant temperature of 20 ± 2 °C. The test samples were kept in this bath until they were removed, superficially dried, and subjected to physical and mechanical tests.For X-ray structural analysis, an X-ray diffractometer system Empyrean with an anode CuK alpha as a source of monochromatic X-ray radiation with Ni radiation filtration was used. Sample preparation consisted of interrupting the hydration process by dehydrating the samples after a definite time and agitating the samples in grinding mortar to the desired fineness of fragmentation.The bulk density of the hardened concrete is determined by measuring the volume of the test specimen on the basis of its dimensions and then determining its mass. The preparation of the test specimens, the test procedure and the evaluation were carried out in accordance with the relevant standard ČSN EN 12390-7 .The flexural tensile strength was determined on 40 × 40 × 160 mm beams placed symmetrically on the supports and uniformly loaded with a hydraulic press perpendicular to the compaction direction. The flexural strength value was calculated as the average of the three determined values. The test procedure and the evaluation were carried out in accordance with the relevant standard ČSN EN 12390-5 .The compressive strength of the concretes was tested on fractions of the test beams after the flexural tensile strength test. The loading was applied perpendicular to the compaction direction. The compressive strength value was calculated as the arithmetic mean of the values determined on the test beam fragments. For this test, the compressive strength was determined after 7, 14, and 28 days. The test procedure and the evaluation were carried out in accordance with the relevant standard ČSN EN 12390-3 .The test blocks are weighed and then placed in a 105 °C oven for 72 h. After the required time has elapsed, the test blocks are retrieved and after cooling down to room temperature they are weighed again. The blocks are placed in a bath so that they do not touch. The bottom is covered with two wooden prisms serving as supports for each beam. The tub is then filled with water, 2 cm above the top surface of the blocks. At predetermined intervals over a period of 72 h, the beams are removed from the water, dried with a damp cloth, and weighed. After 72 h, the samples are placed in a pot of boiling water for 4 h and then weighed again. The weight increments are recorded in a log. The test procedure and the evaluation were carried out in accordance with the relevant standard ČSN EN 206+A2 .


Immunoglobulin G4-related disease (IgG4-RD) is a fibrous inflammatory process related to immunomodulation. The involvement of the pancreato-biliary tract, retroperitoneum/aorta, head and neck, and salivary glands are the most frequently observed disease phenotypes, differing in their epidemiological features, serological findings, and prognostic outcomes. IgG4-RD was combined with oesophageal ulcers, and the patients were infected with cytomegalovirus at the time of the examination. This constituted a huge challenge in the diagnosis and treatment of oesophageal ulcers. We report the case of a 53-year-old male who experienced nausea, vomiting, and anaemia recurrently for many years. According to his medical records, an upper gastrointestinal endoscopy revealed an oesophageal ulcer, and he had had numerous hospital visits for anaemia but with no definitive diagnosis, and he had responded poorly to therapy. However, with persistent symptoms, he came to our hospital and, according to the results of the upper gastrointestinal endoscopy, a serum IgG4 test, and histopathological and immunohistochemical staining, he was finally diagnosed with IgG4-related oesophageal disease combined with a cytomegalovirus infection. We hope that through this case, we can learn more about IgG4-RD and, at the same time, give clinicians a better understanding of IgG4-RD combined with oesophageal ulceration, a new understanding of cytomegalovirus infections, and improved clinical knowledge. IgG4-related disease is a specific type of chronic autoimmune disease. The symptoms of IgG4-related disease are diverse and complex, and they are often accompanied by elevated serum IgG4 concentrations, with typical clinicopathological features, including dense infiltration of lymphocytes/plasma cells and fibrosis, large numbers of IgG4-positive plasma cells in the affected organs, storiform fibrosis, and obliterative phlebitis, which are reported to be the unique and characteristic features of IgG4-RD ,2,3. TheCytomegalovirus (CMV) is a double-stranded DNA virus and is an important member of the herpesvirus family , which uThe aim of this study was to give clinicians more understanding of IgG4-RD combined oesophageal ulceration, a new understanding of cytomegalovirus infection, and improved clinical knowledge. The study also aimed to enrich the clinical data and provide a reference for improving the early diagnosis and prognosis of this disease, and it might offer a reference for treatment.A 53-year-old male from Shanghai’s Song Jiang district in China had experienced nausea and vomiting and anaemia repeatedly for many years before this presentation. He had no previous medical history and no other autoimmune diseases. The patient had been diagnosed with eosinophilic gastroenteritis many years prior, and he made numerous hospital visits during the following years. The patient underwent abdominal magnetic resonance imaging and ultrasonography of the parotid gland in addition to gastric endoscopy at the other hospital, according to the medical records provided by the patient. The endoscopic findings showed a huge oesophageal ulcer. An oesophageal biopsy was performed, but no definitive diagnosis was made. Because of the symptoms recurrence, the patient came to our hospital for further treatment.In September 2021, the patient presented to the gastroenterology department of our hospital with recurrent symptoms accompanied by dizziness and fatigue. The patient showed a poor general condition and an anaemic appearance. The rest of the physical examination was unremarkable.To identify the cause, comprehensive laboratory tests were carried out on the patient, including a routine blood examination, stool tests, renal and liver function tests, human immunodeficiency virus, serum IgG4, immunological tests, CMV IgG and IgM, lymphocyte subsets, CMV DNA, TSPOT, and tumour markers. His urine, renal, and liver function tests were normal; the results of the other laboratory tests are shown in The chest and abdomen contrast-enhanced CT demonstrated wall thickening in the lower oesophagus with enlarged retroperitoneal lymph nodes and a small amount of ascites. An abdominal CT scan of the pancreas was performed and showed normal results .Gastric endoscopy revealed a huge oesophageal ulcer, atrophic gastritis, gastric mucosal erosions, and a duodenal ulcer with lumen stenosis . The patFurthermore, his serum IgG4 levels were 4.05 g/L, validating his diagnosis of IgG4-RD with cytomegalovirus infection. The patient was treated with a proton pump inhibitor (PPI) and blood transfusions, and he was administered 0.25 g/q 12 h ganciclovir intravenously for 2 weeks. His haemoglobin was higher than before, and gastroscopy at follow-up after 2 weeks showed that the oesophageal ulcers had begun healing . He was In recent decades, IgG4-related disease has been recognised as a systemic disease with a fibrous inflammatory process associated with immunomodulation . The preThe clinical symptoms of IgG4-RD are dependent on the affected organs . PreviouApproximately 70% of patients with IgG4-RD have elevated serum IgG4 levels . Serum IBecause its clinical manifestations and endoscopic findings were atypical in the patient, without obvious clinical specificity, when IgG4-RD was suspected based on the elevated serum IgG4 concentrations, histopathology and immunohistochemical staining were carried out for a definite diagnosis of IgG4-RD. Histopathology and immunohistochemistry remain crucial to diagnosis. Typical histopathological features include storiform fibrosis, dense lymphoplasmacytic infiltrate, and obliterative phlebitis . In our IgG4-RD is considered a benign disease, and it needs to be differentiated from malignant tumours and similar benign conditions, such as primary sclerosing cholangitis, multicentric Castleman’s disease, secondary retroperitoneal fibrosis, granulomatosis with polyangiitis, sarcoidosis, and eosinophilic granulomatosis with polyangiitis. The detection of ANA, anti-dsDNA, anti-SSA, anti-SSB, anti-Ro-52, MPO-ANCA, and PR3-ANCA is valuable in differentiated diagnoses of IgG4-RD. However, in this case, these immunological tests were all negative , and theThe difficulty of diagnosis also highlights the therapeutic challenges. This is the first case report of CMV oesophagitis encountered with IgG4-related oesophageal ulceration in immunocompetent patients. Thus, there is no relevant treatment experience to use for a reference. The first-line treatment strategy for IgG4-RD management consists of corticosteroid administration . GanciclMost studies on CMV oesophagitis have focused on patients with organ transplantations or HIV infection. We report a case of CMV oesophagitis in a non-immunodeficient patient. There are also no reports studying the association between IgG4-RD and CMV infection. It is worth exploring whether there is a relationship between IgG4-related disease and CMV infection, or whether this association was found simply by chance. As mentioned in previous reports, CMV reactivation in patients with oesophageal cancer has been reported . IgG4-RDIgG4-related oesophageal ulceration with CMV infection remains a particularly challenging diagnosis for physicians, mainly because of its rarity and the ease of misdiagnosis. For this reason, the key to diagnosis is histological examination. This case might provide a new visual guide for the aetiological diagnosis of oesophageal ulcers for gastroenterologists and will provide a reference for the appropriate therapy.


Because of the recent progress in materials properties, specifically high-strength concrete, further research is needed to evaluate its suitability, understanding, and performance in the modern-day world. This research aims to enhance the performance of ultra-high-strength geopolymer concrete (UHS-GPC) by adding nano-silica (NS) and polypropylene fibers (PPFs). Three 1%, 2%, and 3% different amounts of PPFs and three NS 5%, 10%, and 15% were utilized in the samples. Various performance parameters of UHS-GPC were evaluated, such as fresh property, compressive strength, modulus of elasticity split tensile, flexural and bonding strength, drying shrinkage, load-displacement test, fracture performance, and elevated temperature. The test outcomes showed that by raising the percentage of PPFs and NS to the allowable limit, the performance of UHS-GPC can be improved significantly. The most improved performance of UHS-GPC was obtained at 2% polypropylene fibers and 10% nano-silica, as the compressive, splitting tensile, flexural. Bond strength was improved by 17.07%, 47.1%, 36.52, and 37.58%, and the modulus of elasticity increased by 31.4% at 56 days. The study showed that the sample with 2% PPFs and 10% NS had excellent performance in the load-displacement test, drying shrinkage, fracture behavior, and elevated temperature. At 750°C elevated temperature, the samples’ strength was reduced drastically, but at 250°C, the modified samples showed good resistance to heat by retaining their compressive strength to some degree. The present work showed the suitability of PPFs and NS to develop ultra-high-strength geopolymer concrete, which can be used as a possible alternate material for Portland cement-based concrete. The engineers tried to reduce the volume of binders and replace additional binder-based materials with ordinary Portland cement [3, which led to a 29% decrease in the release of CO2 to the outer atmosphere [Ultra-high-strength concrete is suitable for constructing longer bridges, tall buildings, and structures exposed to aggressive conditions . However3 , which i3 ; the for3 , which m3 [2 . Making 3 [2  0.90 to d cement . Yu et ad cement  revealedmosphere . Comparemosphere . It can mosphere , meta hamosphere , wheat smosphere , metakaomosphere , 19 silimosphere , and themosphere . GPC hasmosphere –25. Contmosphere , 27.it imosphere , 29. Autmosphere  and Ahmemosphere  also usemosphere , and losmosphere . There aMineral admixtures or fillers are supplementary cementitious materials (SCMs)  and are Further research is necessary because of the advancement and challenges related to the GPC, particularly the different properties of ultra-high-strength fiber-reinforced geopolymer concrete (UHS-GPC). This research aims to elevate the awareness of UHS-GPC by examining the influence of nano-silica (NS) and polypropylene fibers (PPFs) on ultra-high-strength geopolymer concrete’s strength and fracture characteristics. PPFs were added in 1%, 2%, and 3% by the binder’s weight, and NS was added in 5%, 10%, and 15% by the binder’s weight. As per the author’s reliable information, no considerable research has been done on the effect of nano-silica on the properties of ultra-high-strength geopolymer concrete modified with polypropylene fibers by evaluating the flow diameter, compression strength, modulus of elasticity, split tensile strength and flexural strength, pullout test, load deflection capacity, drying shrinkage, fracture energy, and lastly the elevated temperature of ultra-high-strength fiber-reinforced geopolymer concrete, which shows the originality of the current work. The present research will assist in growing information on developing ultra-high-strength fiber-reinforced geopolymer concrete with excellent properties in different strength characteristics and against elevated temperatures.2SiO3 and NaOH were utilized as alkali chemicals. The particle size distribution for the fine and coarse aggregate is presented in 2SiO3 and NaOH were obtained from the local chemical industry in Islamabad. Polypropylene fibers (PPFs), as presented in Numerous tests were performed in the present research to evaluate the fresh and strength properties of polypropylene fibers-reinforced UHS-GPC. The following segments highlight the test methods.The influence of adding fiber on the fresh properties of ultra-high-strength GPC was evaluated as flow diameter following BS EN 1015–11 . After mThis research determined the compression performance of entire specimens by utilizing MOE and compression strength. Cylinders of 6 x 12 inches (length x diameter) were used to determine the concrete’s compressive strength following ASTM C 39 . To evalTo determine the bond strength of UHS-GPC, a pullout test was carried out following ASTM C 900 . ConcretHere, L is the embedded length of steel reinforcement, F is the force, and d is the steel diameter in mm.To evaluate the splitting tensile strength (STS) of all the samples, a universal testing machine (UTM) with a limit of 1200 kN. was employed following ASTM C 496 . The rat2, F is the cracking load in Newton, and fst is splitting tensile strength.In the above relationship, A is the concrete’s x-section area in mmTo assess the flexural strength of UHS-GPC, 6 x 6 x 24 inches concrete beams were prepared to perform the three-point bending test following ASTM C78 . A univef is the ultimate highest load in Newton, Fu is the flexural strength, h is the sample’s height, L is the clear distance, and a is the notch’s height in the 3-point bending test.In the above relationship, To evaluate the ductility of UHS-GPC, 6 x 6 x 24 inches concrete beams were cast per ASTM C1609 . A stiffThis test is carried out to examine the change in the length of hardened concrete. Drying shrinkage was performed following ASTM C157  and prisa is reading at a specific age in mm, and CRDb is the reading after 24 hours of mixing in mm.In the above formula, G is the gauge length in mm, CRDIn this test, a servo-controlled hydraulic jack is utilized on the concrete sample suspended on the beam. The beam was 400 mm in length with 100 mm in depth. Fracture energy was evaluated by installing a linear variable differential transducer (LVDT) on the beam subjected to a four-point bending test. Its test setup is presented in f is the fracture energy, σs is the displacement, mg is the concrete’s weight, wo is the area under the force vs displacement curve, and A is the area.In the above relationship, GThe relationship in (E) evaluated the critical intensity factor.max is the highest force, A is the ratio between the depth of notch and depth of the specimen, ao is sample’s depth of the notch.In the above relationship (F), l is the sample’s clear span, b is the sample’s width, d is the sample’s depth, Pst phase shows the start of heating the temperature till it reached its desired temperature, 2nd phase shows the desired heat was sustained for 2.5 hours, and 3rd phase shows the cooling of the sample after heating it to the needed heat. Afterwards, the furnace was let cooled at the rate of 2.5°C per minute to evade thermal shock to the concrete samples. When the furnace was thoroughly cooled to ambient temperature, the samples were kept in the lab for 24 hours at ambient temperature. Then, the samples were tested to evaluate the loss in mass and strength of exposure to high temperatures.In this test, concrete samples were exposed to high temperatures, and their effect on concrete compressive strength was evaluated. An electric plus gas furnace was employed for this test. When the desired heat was attained, the heat temperature was kept the same for 2.5 hours. The heating and cooling regime are presented in 2” behaved as nuclei for the precipitation of dissolved samples from silica fume the nano-silica. Das et al. [The impact of adding PPFs on the fresh property of UHS-GPC is provided in s et al.  revealeds et al. . Mustakis et al.  revealeds et al. .2 value of more than 75% for both the relationship, which shows the strong co-relation between the compressive strength and modulus of elasticity at 28 and 56 days.Co-relation analysis was performed between compressive strength and modulus of elasticity for 28 and 56 days, as presented in 2 was noted to be near unity and estimated values with more than 80% constancy for split tensile strength, demonstrating the accuracy of the test outcomes.The effect of NS and fibers on STS is displayed in 2 were noted to be near unity and projected values with the consistency of more than 80% for flexural strength, which establishes the correctness of the test outcomes.To evaluate the flexural strength and develop a statistical co-relation among entire strength numbers of compressive and splitting tensile strength, linear regression analysis is carried out, as represented in As discussed earlier, a drying shrinkage test was performed on all the concrete samples at 3, 7, 14, 21, 28, 56, and 90 days of age and then compared with the control concrete to assess the improvement in the performance of drying shrinkage. The test outcome after the 56 days was the base for determining the drying shrinkage because, after the 56 days, the strain values become stable. The test results of drying shrinkage are presented in The fracture performance of concrete samples was evaluated utilizing Formula , which iLoss in weight and the residual compressive strength of all concrete samples were evaluated after their exposure to the specific elevated temperature. The samples were tested after 24 hours after their exposure to high heat. The results of the loss in weight of concrete samples after their exposure to high heat are presented in The impact of PPFs and NS on the strength properties of UHS-GPC are considered and conferred in the present research. The subsequent conclusions are obtained from the current work.The addition of PPFs decreased the slump value of freshly mixed UHS-GPC samples.The maximum improvement of bond strength was noted to be 14.41 MPa and 17.3 MPa, which is the improvement of 26.47% and 37.58% at 28 and 56 days for the sample with 10% nano-silica and 2% PPFs.When the amount of NS was more than 5%, i.e., at 10% NS, a firm bonding characteristic was observed among the PPFs and the matrix.The highest splitting tensile strength was 15.4 MPa and 17.6 MPa at 10% NS and 2% PPFs which is 44.15% and 47.1% more splitting tensile strength than the control sample at 56 and 90 days.The co-relation analysis showed the accuracy of test results as the values of the R square tended to be close to unity.The inclusion of PPFs enhances flexural strength. The FS improved from 22.7 MPa to 25.43 MPa with 1 to 2% of PPFs at 90 days.The load-displacement curve of the reference specimen displayed similar behavior as compared with the modified sample up to its first cracking. Still, when PPFs and NS were added, the load-displacement curve went up, and the sample with 2% PPFs and 10% NS had the highest load-carrying capacity against its corresponding load.When compared with the control sample at the age of 90 days, the drying shrinkage was decreased by 12.97% at 2% PPFs and 10% NS, which is very significant.When the PPFs and NS were added to the concrete, it was noticed that fracture energy was enhanced by increasing the polypropylene fibers and nano-silica.When the percentage of PPFs and NS in concrete was raised to 2% and 10%, it was noted that more stresses were needed to open the present cracking in the concrete sample, which improved the critical stress intensity factor.During the elevated temperature test, the concrete lost the minimum weight and compressive strength at 250°C and yielded the highest weight and compressive strength at 750°C.S1 Table(XLSX)Click here for additional data file.