Clostridium, Lachnoclostridium, and Akkermansia did not regain their relative abundance following six weeks of antibiotic discontinuation. Mice treated with antibiotics experienced delayed gastrointestinal transit and altered expression of neuronal markers. The anomalies of the ENS persisted for up to 4 weeks after the antibiotic interruption; the expression of neuronal HuC/D, glial-derived neurotrophic factor (Gdnf), and nerve growth factor (Ngf) mRNA transcripts did not recover. In this study, we strengthened the idea that antibiotic-induced gastrointestinal dysmotility directly correlates with gut dysbiosis as well as structural and functional damage to the ENS.The side effects of antibiotic treatment directly correlate with intestinal dysbiosis. However, a balanced gut microbiota supports the integrity of the enteric nervous system (ENS), which controls gastrointestinal neuromuscular functions. In this study, we investigated the long-term effects of antibiotic-induced microbial dysbiosis on the ENS and the impact of the spontaneous re-establishment of the gut microbiota on gastrointestinal functions. C57BL/6J mice were treated daily for two weeks with antibiotics. After 0–6 weeks of antibiotics wash-out, we determined (a) gut microbiota composition, (b) gastrointestinal motility, (c) integrity of the ENS, (d) neurochemical code, and (e) inflammation. Two weeks of antibiotic treatment significantly altered gut microbial composition; the genera  The microbiota refers to a group of beneficial and potentially harmful microorganisms that colonize and interact as a community within the host’s specific area . One of Bifidobacterium and species producing short-chain fatty acids in 12 healthy young adult males treated with a cocktail of antibiotics. The antibiotic-induced effects appeared to be evident up to six months after antibiotic discontinuation.Antibiotics are considered gut-dysbiosis-promoting agents, which can significantly affect the diversity and richness of the microbiome. Antibiotics have short- and long-term effects on the microbiome, and the recovery from these effects depends on many factors, such as the antibiotic spectrum of activity, dose, duration of treatment, and the combination of antibiotics ,15. The The reduction in richness and the change in the composition of the microbiome might indirectly affect both the ENS and gastrointestinal functions. It has been reported that mice treated with antibiotics suffered drastic changes in immune cell populations, an enlarged cecum, and narrower villi. The structural alterations are accompanied by functional alterations in the transit time along the whole ileum . Moreovep < 0.02) for both the V2 and V6 regions. The severe reduction in copy number in the bacterial genome persisted for two weeks after antibiotic discontinuation (2 weeks w/o), and recovered starting from the fourth week of wash-out (p < 0.05 vs. vehicle). Interestingly, the OTU relative abundance shrinkage persisted for two weeks after antibiotic discontinuation (p = 0.002 vs. vehicle-treated group). Samples from antibiotic-treated mice sacrificed immediately after the treatment or two weeks after antimicrobial discontinuation displayed greater dissimilarity along PC2 , indicating impaired gastrointestinal motility. On the contrary, we observed reduced transit time two and four weeks after antibiotic discontinuation (p < 0.05 vs. vehicle). Ileal motility alterations disappeared after six weeks of the antibiotic wash-out  finely regulates most of the gastrointestinal activities and the gut microbiota preserves the integrity of the ENS , we eval2+-modulated protein of the enteric glial cells, was also diminished 3-fold following antibiotic treatment , nerve growth factor (Ngf), ciliary neurotrophic factor (Cntf), and neurotrophins (Ntf) 5 and 3  and housed in a temperature- and humidity-controlled room under a 12 h light/dark cycle. Mice were housed in the same room and maintained by the same personnel. All animals were specifically pathogen-free and given a standard chow diet and tap water ad libitum.Freshly prepared antibiotic solutions (Abx) consisting of 50 mg/kg vancomycin, 100 mg/kg neomycin, 100 mg/kg metronidazole, and 100 mg/kg ampicillin  were administered (100 µL/mouse) every 12 h for 14 days by oral gavage using a stainless-steel feeding tube . ControlThe experimental protocols were approved by the Animal Care and Use Ethics Committee of the University of Padova under license from the Italian Ministry of Health, and they were found to be in compliance with national and European guidelines for the handling and use of experimental animals.Cecal contents were collected at the specified time points . Amplicons were generated using the modified universal bacterial primer pairs 515F (5′-TCGTCGGCAGCGTCAGATGTGTATAAGAGCAGGTGCCAGCMGCCGCGGTAA-3′) and 806R (5′-GTCTCGTGGGCTCGGAGATGTGTATAAGAGACAGGGAACHVGGGTWTCTAAT-3′) according to the Illumina MiSeq 16S Metagenomic Sequencing Library Preparation protocol . Bioinfog, 15 min, 4 °C). Fluorescence analysis was performed at 494/521 nm . Data are expressed as a percentage of fluorescence per segment. Gastrointestinal transit was calculated as the geometric centre of distribution of the fluorescent probe [Fluorescein isothiocyanate–dextran  dissolved in phosphate-buffered saline PBS, 6.25 mg/mL) was administered in a total volume of 200 μL by intragastric gavage [ mg/mL waMice fasted for 16 h were lightly anaesthetized with isoflurane , and a 2 mm glass bead was inserted into the distal colon at 2 cm from the anus. Mice readily regained consciousness and were placed individually in a cage. Distal colonic motility was determined by monitoring the time required for the expulsion of the glass bead, reported as the time (in seconds) of bead retention .In a separate set of experiments, non-anaesthetized mice were placed in clean cages; the number of pellets expelled over an hour was determined. Colonic motility assays were always performed in the morning hours (between 8 and 10 a.m.) to ensure reproducibility among the experiments at the different time points.Ileal and colon sections (5 µm thick) were cut from formalin-fixed and paraffin-embedded full-thickness specimens. Slides (6–8 per mouse) were subjected to standard haematoxylin and eosin (H&E) staining for routine histological examination. A minimum of 10 independent fields per animal were examined using a Leica microscope equipped with a digital camera.Segments of distal ileum (4–6 cm long) were flashed with PBS, filled with fixative solution  and immersed in the same fixative solution . After 14, 1 mM NaF) containing protease inhibitors . After 30 min at 4 °C, particulate material was removed through centrifugation  and protein concentration in the supernatants was determined using the bicinchoninic acid method (Pierce). Proteins were fractionated through an SDS-PAGE gel, immobilized onto a nitrocellulose membrane, and subsequently subjected to immunoblot analysis. The membranes were blocked for 1 h with 5% non-fat dry milk in PBS with 0.05% Tween 20. Membranes were probed with appropriate primary antibodies . LMMPs were homogenized in RIPA buffer , and interleukin (IL)-1β, interferon (IFN)-γ, and tumour necrosis factor (TNF)-α were quantified using an enzyme-linked immunosorbent assay . Data were normalized by total protein content measured using the bicinchoninic acid method.LMMPs were homogenized in phosphate-buffered saline (PBS) (1:10 wt/vol) supplemented with protease inhibitors . The samples were centrifuged  and plotted as mean fold expression. Oligonucleotides and annealing temperatures used for qRT-PCR are listed in Total RNA was extracted from LMMP samples using the EZNA lysis buffer . Contaminating DNA was removed through DNase I treatment (Omega Bio-tek). Gene expression was assessed using the iTaq Universal SYBR Green One-Step Kit . The expression of the targeted mRNA was normalized to 18S ribosomal RNA  except for gastric emptying and geometric centre, which are reported as median ± SD. One-way analysis of variance followed by the Bonferroni multicomparison test was used to compare the data of three or more groups. The statistical analysis was performed using GraphPad Prism 3.03 software .


Burkholderia pseudomallei, have evolved mechanisms to efflux certain antibiotics and manipulate the host response. New treatment strategies are therefore required, such as a layered defense approach. Here, we demonstrate, using biosafety level 2 (BSL-2) and BSL-3 in vivo murine models, that combining the antibiotic doxycycline with an immunomodulatory drug that targets the CD200 axis is superior to antibiotic treatment in combination with an isotype control. CD200-Fc treatment alone significantly reduces bacterial burden in lung tissue in both the BSL-2 and BSL-3 models. When CD200-Fc treatment is combined with doxycycline to treat the acute BSL-3 model of melioidosis, there is a 50% increase in survival compared with relevant controls. This benefit is not due to increasing the area under the concentration-time curve (AUC) of the antibiotic, suggesting the immunomodulatory nature of CD200-Fc treatment is playing an important role by potentially controlling the overactive immune response seen with many lethal bacterial infections.Antimicrobial resistance continues to be a global issue. Pathogens, such as IMPORTANCE Traditional treatments for infectious disease have focused on the use of antimicrobial compounds (e.g. antibiotics) that target the infecting organism. However, timely diagnosis and administration of antibiotics remain crucial to ensure efficacy of these treatments especially for the highly virulent biothreat organisms. The need for early antibiotic treatment, combined with the increasing emergence of antibiotic resistant bacteria, means that new therapeutic strategies are required for organisms that cause rapid, acute infections. Here, we show that a layered defense approach, where an immunomodulatory compound is combined with an antibiotic, is better than an antibiotic combined with a relevant isotype control following infection with the biothreat agent Burkholderia pseudomallei. This approach has the potential to be truly broad spectrum and since the strategy includes manipulation of the host response it's application could be used in the treatment of a wide range of diseases. Burkholderia pseudomallei is the causative agent of melioidosis. The bacterium has evolved mechanisms to evade innate host defenses and to persist  route with 5,000 CFU Burkholderia thailandensis . At 6 h post-infection, mice were treated either with CD200-Fc  or IgG isotype control (i.n. administration at 1.25 mg/kg of body weight) and monitored for 3 days. At the end of the study, mice were culled and lung tissue was removed for bacterial enumeration. In the lung, following treatment with CD200-Fc, there was a lower bacterial load than mice treated with IgG; however, this difference did not reach statistical significance  B. pseudomallei (K96243) via the aerosol route (using the Biaera aerosol management platform) and treated at 1 day post-infection with CD200-Fc or IgG control via the intraperitoneal (i.p.) route. Culls were performed at day 3 post-infection, and organ tissues were collected. Bacterial burden in the lung and spleen was significantly reduced following CD200-Fc treatment compared with that of the control  compound has been used by the company as a stepping-stone to clinical trials with a human analogue.Doxycycline was used in these studies, which although it has been recommended for eradication in the past , it has 50) B. pseudomallei (K96243). At days 1, 3, and 7, all treatment groups received i.p. injections of either research-grade CD200-Fc, haCD200-Fc (1.25 mg/kg to 3 mg/kg) or relevant IgG1 control. For the first 7 days post-infection, all groups were orally administered daily with doxycycline monohydrate  (100 mg/kg); the dose chosen is known to be a suboptimal therapeutic dose (P < 0.0001)   and B. I 0.0001)  and B. T 0.0001) –21 but a0.0001) – and D, iP < 0.05) following treatment with haCD200-Fc compared with the isotype control  study was conducted. Naive mice were administered orally with either doxycycline and/or the haCD200-Fc compound as a single dose on day 0. Animals were euthanized from 0.5 to 192 h and blood was collected for analysis of the compounds. Antibiotic concentration in the plasma indicated that there were no major advantageous changes in antibiotic drug concentration  when it was administered in conjunction with haCD200-Fc . The antB. pseudomallei infection.Overall, our data suggest that an immunomodulator and antibiotic combination therapy approach is of benefit for the treatment of melioidosis and should be considered alongside other layered defense approaches. For example, it has been documented recently that the combination of a vaccine with an antibiotic  or the cAnimal studies were performed in accordance with the United Kingdom Scientific Procedures Act  1986 and the United Kingdom Codes of Practice for the Housing and Care of Animals Used in Scientific Procedures, 1989. Investigations involving animals were carried out according to the requirements of the UK Animal (Scientific Procedures) Act 1986 under the authority of Project License P1D46FB69 granted by the UK Home Office and an Animal Care and Use Review Office (ACURO) Appendix. This project license was approved by the Animal Welfare and Ethical Review Body (AWERB), Dstl, Porton Down which includes a review panel consisting of Named Veterinary Surgeon (NVS), Named Animal Care and Welfare Officer (NACWO), Named Training and Competency Officer (NTCO), Named Information Officer (NIO), Home Office Liaison Contact (HOLC) and independent non-technical members.


Date palm fiber (DPF) is normally used as fiber material in concrete. Though its addition to concrete leads to decline in durability and mechanical strengths performance. Additionally, due to its high ligno-cellulose content and organic nature, when used in concrete for high temperature application, the DPF can easily degrade causing reduction in strength and increase in weight loss. To reduce these effects, the DPF is treated using alkaline solutions. Furthermore, pozzolanic materials are normally added to the DPF composites to reduce the effects of the ligno-cellulose content. Therefore, in this study silica fume was used as supplementary cementitious material in DPF reinforced concrete (DPFRC) to reduce the negative effects of elevated temperature. Hence this study aimed at predicting the residual strengths of DPFRC enhanced/improved with silica fume subjected to elevated temperature using different models such as artificial neural network (ANN), multi-variable regression analysis (MRA) and Weibull distribution. The DPFRC is produced by adding DPF in proportions of 0%, 1%, 2% and 3% by mass. Silica fume was used as partial substitute to cement in dosages of 0%, 5%, 10% and 15% by volume. The DPFRC was then subjected to elevated temperatures between 200 and 800 °C. The weight loss, residual compressive strength and relative strengths were measured. The residual compressive strength and relative strength of the DPFRC declined with addition of DPF at any temperature. Silica fume enhanced the residual and relative strengths of the DPFRC when heated to a temperature up to 400 °C. To forecast residual compressive strength (RCS) and relative strength (RS), we provide two distinct ANN models. The first layer's inputs include DPF (%), silica fume (%), temperature (°C), and weight loss (%). The hidden layer is thought to have ten neurons. M-I is the scenario in which we use RCS as an output, whereas M-II is the scenario in which we use RS as an output. The ANN models were trained using the Levenberg–Marquardt backpropagation algorithm (LMBA). Both neural networking models exhibit a significant correlation between the predicted and actual values, as seen by their respective R = 0.99462 and R = 0.98917. The constructed neural models M-I and M-II are highly accurate at predicting RCS and RS values. MRA and Weibull distribution were used for prediction of the strengths of the DPFRC under high temperature. The developed MRA was found to have a good prediction accuracy. The residual compressive strength and relative strength followed the two-parameter Weibull distribution. Even with concrete, long-time exposure to high temperature causes significant loss in structural integrity and strength. Furthermore, spalling in the concrete structure due occur due to induced chemical reactions and physical changes in the concrete’s microstructure when exposed to high temperature for a long period.. When concrete spall, this will significantly affect the ultimate limit and serviceability limit states of the structure and results to failure of the structure. This will have a significant effect on the durability and design life of the structure4. Therefore, it is necessary to comprehend the relationship between high temperature exposure and the properties of concrete such as durability, mechanical strengths, toughness, and brittleness. This will guide in detecting and evaluating the level of damage instigated by the high temperature on the concrete4. Several factors influence the behavior of concrete when exposed to high temperature. These includes the type and properties of the aggregates used, the type and amount of cement, additives and supplementary cementitious materials added, type and amount of fiber added if any5. To minimize the undesirable effects of elevated temperature on the properties and performance of concrete, it is necessary to be cautious when choosing the basic materials for making the concrete. Evaporation and loss of chemically enclosed water from hydration products of cement reaction in the concrete microstructure initiate when the heat surpasses 110 °C, at this stage the effect of temperature exposure on the concrete’s properties begin to be noticed. As the temperature rises and exceeds 300 °C, dehydration, and thermal expansion of the aggregate’s initiates, causing severe microcracks to form within the matrix of the concrete. As the heat reaches 400 °C, Portlandites disintegration transpires, and when the temperature reaches 600 °C, the disintegration of calcium silicate hydrate (C–S–H) takes places. At about 800 °C, the loss in the hydration products through decomposition becomes highly severe, resulting in substantial loss in compressive strength, ductility, integrity, and durability of the concrete7.Concrete can be used in structures that are exposure to both normal and sever conditions. For normal conditions, there is not much challenge in using the concrete. However, for exposure conditions such as acidic and salt environment, elevated temperature, oil and gas environment, there is need for careful selection of the constituent materials for producing the concrete in such a way that its durability performance is not significantly affected. Even with these, concrete has more advantages over other building materials when used in areas of high exposure conditions. For example, when steel is used in areas of alkaline or chlorine environment, there is high risk of corrosion compared to when reinforced concrete is used. Similarly, in high temperature exposure, plastics, steel and timber tends to loss their structural integrity faster than concrete8. Studies by Noumowe9 disclosed that the addition of 1.8% polypropylene fiber to concrete enhanced its compressive and split tensile strengths as well as its elastic modulus at 200 °C. Another findings by Gencel, Nodehi10 observed a gain in compressive strength of concrete when 3% basalt fibers was added and heated at 800 °C. Amin and Tayeh11 testified an increase in the flexural and compressive strengths of lightweight concrete with addition of 0.4% polypropylene (PP) and glass fiber. They found that at 400 °C, PP fiber improved the compressive strength by 70%, while glass fiber enhanced the compressive strength by 76%. Talaei and Mostofinejad3 reported that the addition of 0.5% steel fiber improved the residual compressive strength of concrete by 20% and 30% at 400 °C and 800 °C respectively.One of the remedies taken to reduce the harmful effect of elevated temperature and improve the concrete’s resistance to high temperature is by adding fibers to the concrete. The fibers are expected to delay the formation and limit the spread of heat induced cracks, and forestalling spalling occurrence in the concrete13. Some advantages of using DPF in composites like mortar and concrete includes enhanced ductility and thermal insulation15. On the contrary, the addition of DPF to concrete and mortar results in significant loss in strengths and durability due to escalation in porosity within the cementitious caused by the DPF’s hydrophilic nature18. To lessen the damaging effect of the DPF on the properties of concrete and mortar, the DPF is usually treated in alkaline solution. This will make the DPF surface rougher and hence improve the adhesion or bond between the fiber and cementitious matrix. Furthermore, pozzolanic materials like silica fume were added to the DPF to densify its microstructure and reduce the pores produced by the DPF and hence enhance its strength10. When DPF is used as a natural fiber in concrete or mortar that will be exposed to high temperature, there is a very high probability that the DPF may degrade easily due to its organic nature and high amount of ligno-cellulose19. Furthermore, as DPF addition to cement composite increase the porosity of the composite microstructure, this will hasten the deterioration of the composite under high temperature, as it will hasten the formation and growth of microcracks due to heat, hence leading to significant decline in strength. Other researchers have also studied the effects of elevated temperature on concrete produced using different natural fibers. Aluko, Yatim20 reported that natural fibers containing lignocellulose such as hemp, sisal, coir, and jute fibers can aid in restraining explosive spalling in ultra-high-performance concrete (UHPC) subjected to high temperatures compared to in conventional unreinforced concrete. This is normally achieved through increased porosity and voids in the microstructure of the UHPC by the lignocellulose fibers. Zhang, Tan21 investigated the effect of natural fiber (jute) as a replacement to PP fibers in UHPC subjected to high temperature. They observed that the jute fiber swells by absorbing water during mixing and service life and shrinks when exposed to high temperature. This shrinking of the fiber at high temperature creates spaces between voids between the fiber and cement matrix which can have effects on the permeability of the concrete at high temperature. They also observed that with the addition of 3 kg/m3 of jute fiber to the UHPC, the compressive strength increased at exposure to 200 °C and reduction in strength at temperature above 400 °C. However, with the addition of 5 kg/m3 and 10 kg/m3 jute fiber to the UPHC, there was reduction in compressive strength even at room temperature. When the UHPC was subjected to temperature above 400 °C, there was a significant decline in compressive strength. Ozawa, Kim22 also reported that the use of jute as natural fiber in high strength concrete (HSC) caused a reduction in compressive strength by up to 40% when heated to a temperature of 100 °C, while at 200 °C and 300 °C, the HSC reinforced with jute fiber recovered its full strength. The jute fiber was able to prevent explosive spalling in the HSC.DPF is a waste material obtained in the form of woven mesh from date trees. The DPF is easy to process for use as a natural fiber in cement composites. When compared to synthetic fibers, the DPF has easier and lower cost of processing, and lower cost to strength ratios25. The application of neural networks in a variety of human endeavors is a subject that is now receiving a lot of attention. Particularly in the field of construction, use of neural networking is treated as best prediction scheme like in order to semantically segment concrete crack images, Dung26 suggested a crack detection system based on deep Fully Convolutional Networks (FCN). The backbone of the FCN encoder, three alternative pre-trained network architectures, were tested for image classification on a public concrete fracture. The average precision achieved by the FCN network is around 90%. The suggested technique for concrete fracture detection was validated using images taken from a film of a cyclic loading test on a concrete specimen. The evaluation of crack density and the reasonable detection of cracks were both shown to be accurate. A deep neural network model was proposed by Nguyen, Kashani27 to forecast the compressive strength of foamed concrete. To enhance the performance of the deep neural network model, a new, high-order neuron was created. Moreover, the rectified linear unit activation function and cross-entropy cost function were used to improve the model's performance. Moreover, using a particular data set, the current model was used for predicting the compressive strength of foamed concrete. The findings were then compared with those of other machine learning techniques, such as the Conventional Artificial Neural Network (C-ANN) and Second-Order Artificial Neural Network (SO-ANN). The results showed that density, followed by the water-to-cement and sand-to-cement ratios, had a significant impact on the compressive strength of foamed concrete. The proposed model can assist scientists and engineers in the mixture design optimization of foamed concrete by offering a trustworthy prediction tool. To forecast the compressive strength of rubber concrete, Ly, Nguyen28 presented a novel Deep Neural Network model generation process. In order to achieve this, a rubber concrete database was meticulously created, comprising a set of input parameters for the binder, aggregate, and other relevant concrete variables, while the compressive strength was taken into account as an output. A statistical study of the model's prediction outputs is combined with a thorough analysis of the number of hidden layers and the neurons in each layer as part of the creation of the DNN model. The findings demonstrate that, in terms of a number of well-known performance indicators, including coefficient of determination, root mean square error, and mean absolute error, the DNN model outperforms conventional neural network topologies. Also, the proposed DNN model displays higher prediction accuracy than results from earlier publications that used other machine learning algorithms from the literature. The DNN algorithm underwent a sensitivity study utilizing partial dependence plots in order to thoroughly examine the impact of each individual input variable on the anticipated compressive strength of rubber concrete. Using Response Surface Methodology (RSM) and Artificial Neural Networks (ANN) techniques, Kursuncu, Gencel29 investigated the effects of Waste Marble Powder (WMP) and Rice Husk Ash (RHA) partially substituting fine aggregate and cement into Foam Concrete (FC) on compressive and flexural strength, porosity, and thermal conductivity coefficient. In the experimental design, the WMP and RHA parameters were determined as three levels, while the foam parameter was calculated as two levels. It was discovered that the ANN technique worked well for estimating the answers. It was discovered that the RSM method worked well for both estimating responses and figuring out the efficient parameters. The recent studies in this regard can be accessed in Refs32.Neural networking is one of the best prediction approaches when compared to the traditional methods of statistical forecasting, classification, and recognitionBased on the existing study, there are scanty literature that used ANN to predict the properties of silica fume modified DPFRC under high temperature. Hence, in this study ANN was used to predict the residual compressive strength and relative strength of the DPFRC exposed to high temperature condition. Additionally, multivariable regression and Weibull distribution were used for statistical analysis and establishing models for estimating the compressive strengths of the DPFRC concrete under high temperature and carry out reliability analysis of the concrete under elevated temperature.33 specifications. The physical and chemical properties of the binder materials are summarized in Table Silica fume and Portland cement were the binder materials employed in this study. The cement conformed with ASTM C150/C150MDPF was adopted as a fiber material in this study. The fiber was collected from a neighboring farm in its raw state as shown in Fig. 34. Cement was partially replaced with silica fume in the mixes. The dosages of replacements were 0%, 5%, 10% and 15% by volume of cement. To address the effect of variation in water-to-binder ratio in the concrete, a polycarboxylate based water reducing admixture (superplasticizer) was added. The dosage of the admixture was 1% by weight of binder materials in all the mixes. The mixes were produced using the different dosages of silica fume and DPF as presented in Table The processed DPF was added at varying amounts of 0%, 1%, 2% and 3% by mass of cementitious materials to the concrete. The design of the concrete mix was carried out using the absolute volume method highlighted in ACI 211.1R21. The cement used was also ensured to be free from agglomeration, impurity, and lumps. A rotating drum mixer type available in the laboratory was used for mixing the fresh concrete. The fine aggregate, silica fume and cement were emptied to the mixer, they were then thoroughly mixed for about 45 secs. The DPF and part of the mixing water combined with superplasticizer were added gradually while mixing was going on. The coarse aggregate and remaining part of water combined with superplasticizer were added. The mixing progressed and was stopped after a completely homogenous mix was obtained. The ready mixed concrete in the mixer is shown in Fig. The developed mix proportions were produced in the laboratory for testing. Each of the constituent material for the mix under consideration was weighed. The batching, mixing, and casting of the concrete samples were accomplished following the procedures outlined in ASTM C192/C192Mi. The samples were subjected to elevated temperature by placing them inside an electric furnace. Each of the mixes was heated at varying temperatures of 24 °C 200 °C, 400 °C, 600 °C and 800 °C for 2 h exposure periods in the electric furnace as shown in Fig. F. Equation  and Relative Strength (RS). In detail, neural network is composed of three different layers. Four different inputs, namely date palm fiber, temperature, silica fume, and weight loss are considered in the first layer. The hidden layer owns 10 neurons and case-wise outputs are taken in the last layer. M-I is the case when we take RCS as an output while M-II is the case when we carried RS as an output. The selection of inputs and outputs are offered in Table. Use of neural networking models to make predictions is considered by various researchers in different research scenariosFigure Tan-Sig transfer function Eq.  is used 40, and has been reported in this study to enhance readability and ease of understanding the findings in this study based on the ANN, Weibull distribution and multivariable regression analysis models developed. The weight loss of the DPFRC intensified with rise in temperature which was due to the loss of capillary water and gels from the microstructure of the concrete. At higher temperatures of 600 °C and above, the weight loss was due to evaporation of chemically bound water from the hydration products. Furthermore, there was an escalation in weight loss with increment in percentage addition of DPF to the concrete. This was because DPF creates more voids in the concrete, therefore under high temperature capillary water and chemically bound water evaporates easily from the voids, thereby escalating the weight loss in the DPFRC. The partial substitution of cement with silica fume in the DPFRC decreased the weight loss when heated up to a temperature of 400 °C. This is due to the pozzolanic reaction between the silica fume and cement hydration products which densified the concrete microstructure and prevent the evaporation of water from the concrete under high temperature41. The strengths of the DPFRC improved when subjected to elevated temperature of up to 400 °C regardless of the proportions of DPF and silica fume in the mixes. This improvement in strength can be linked to the formation of excess tobermorite from the hydrothermal reactions between the SiO2 from silica fume and calcium oxide from cement. The addition of DPF to the concrete resulted in reduction in residual and relative strengths of the concrete due to premature failure occurring in the concrete due to voids created by the DPF in the microstructure of the concrete. Additionally, the poor adhesion between the DPF and cement paste also caused a reduction in strengths at any temperature. The strengths of the DPFRC improved with partial replacement of not more than 10% cement with silica fume at a temperature of up to 600 °C. The improvement in strength might be due to the consumption of excess Portlandites (Ca(OH)2) thereby inhibiting its conversion to lime at high temperature, hence avoiding the damage that can be caused by this reaction41.The results of the weight loss, residual compressive strength, and relative strengths of the DPF reinforced concrete containing silica fume as supplementary cementitious material presented in Table Both RCS and RS are predicted by using ANN models namely M-I and M-II respectively. Figures From Fig. From Fig. Figure Tables A statistical modelling using multivariable regression analysis (MRA) was carried out to establish model equations for calculating or forecasting the properties of the DPFRC exposed to elevated temperature using DPF, silica fume and temperature as the inputs.42.The basic globalized MRA equation is expressed in form of linear equation expressed as Eq. 42.7\docuFor which y denotes the response/output, Ψ is the coefficient of the intercept, Ζ is the linear regression coefficients.42.i represents the coefficient of the 1st order polynomial in the equations, and Ζij represents the coefficient of the 2nd order polynomial in the equation, n is the number of input variables, and Ψ is the constant of regression.However, as most of the relationships between the responses/outputs and variables contains some curvature, non-linear multi-variable regression analysis using second-order polynomial will improve the prediction accuracy and reduce the errors in the models. The global second-order non-linear MRA equation is expressed as Eq. 42.8\docuIn this research, the non-linear MRA was employed to develop models for forecasting and calculating the strengths and weight loss for the DPFRC concrete exposed to high temperature.The developed mathematical equations for the prediction of the weight loss, residual compressive strength and relative strength of the DPFRC containing silica fume under elevated temperature is given as Eqs. –11) res res11) rL represents the weight loss in %, Fc and RC are the residual and relative compressive strengths respectively, in MPA and % respectively. T is temperature in °C, D is DPF in %, and S is silica fume in %.In the above Eqs, WP < 0.05), the statistical significance for all the models were checked. All the models were found to be statistically significant based on the significance test (P < 0.05), as their P-values are less than 0.05. Hence the statistical null hypotheses for all the models were false and rejected. In terms of R2, higher values of R2 clarified the high degree of correlation of the models with the experimental results and hence high predicting accuracy. From Table 2 value of 0.928 which is very close to 1, and hence the model is said to have a very high accuracy and prediction. For the residual and relative strength models, their R2 values of 0.818 and 0.786 are said to be very good and also close to 1, and hence the models have good correlation and prediction ability. all models can be said to have excellent R2 scores which is ≥ 0.9. Further model accuracy test was done by comparing the standard errors (SE) for each model relative to its mean square values. The low SE relative to mean square for each of the model explains the accuracy of prediction with less errors.Table The normal probability graphs for the weight loss, residual compressive strength and residual strength models are presented as Fig. 2 of 0.93 as seen in Fig. 2 of 0.79. From the plots only about 7%, 18% and 21% of the total data for the weight loss, residual compressive strength and relative strength models respectively were not perfectly fitted with the developed mathematical models. Consequently, the proposed models for predicting or forecasting the weight loss and strengths of the DPFRC containing silica fume under high temperature can be said to have a reasonably good to high prediction accuracy.Figure 43. In addition, Weibull statistical analysis can also be used to analyse quasi-brittle materials44. The fracture toughness and strengths of quasi brittle materials like rocks followed the Weibull distribution., where the two and three parameters Weibull distribution functions were utilized for analysing the rock fracture’s probability45. Concrete is considered as a quasi-brittle composite material due to variation in its strength and other mechanical properties which are dependent on the type and quantity of cementitious materials, aggregate type and strength, temperature and humidity, casting and curing methods. Therefore, concrete’s strength and other properties can be analysed using Weibull distribution43. Previous research has adopted Weibull distribution for the analysis of concrete’s properties. He and Xie46 analysed the compressive and tensile strengths of concrete using Weibull distribution and reported a very high correlation for the models where the concrete strengths obeyed the two-parameter Weibull distribution function. Kencanawati, Iizasa47 used Weibull distribution for the analysis of the strengths and reliability of recycled aggregate concrete (RAC). They found a good correlation between the Weibull analysis and mechanical strengths of the concrete and concluded that the Weibull distribution can be used for reliability analysis of the RAC. The dynamic and static mechanical properties of FRC have been evaluated using Weibull distribution statistical method and was reported to have a high prediction and correlation49. The drop weight impact resistance test on concrete was analysed statistically using Weibull distribution functions50. The Weibull distribution was found to be a suitable statistical analysis method for impact and fatigue tests on concrete due to its nature of enhancing hazard function, which characterize the real behaviour of engineering constructions under repeated loads51. Zheng, Cheng52 modified the Weibull distribution to a simplified form with lesser parameters and containing the pre-peak and post-peak stresses in shotcrete. They found that that the modified Weibull distribution model effectively quantified the failure mechanism of the shotcrete, and the Weibull model was reasonably in good correlation with the experimental data, with the model having an acceptable reliability. Guo, Qiao53 used the two and three parameters Weibull distributions to carryout stochastic analysis for the assessment of concrete structure’s durability. They found that the Weibull distribution is well fitted for the analysis of the life data and durability of the concrete structures throughout its service life. The three parameters Weibull distribution model has the best fit compared to the two parameters Weibull distribution. Shahraki, Hua54 employed Weibull distribution to establish probabilistic models for predicting the residual compressive strengths of calcareous and siliceous concrete when exposed to temperature between 200 to 1000 °C for 2 h exposure. They defined the parameters of the Weibull distribution as a function of temperature in continuous closed-form solutions. Their findings showed that the model for the residual compressive strength followed the Weibull distribution, and the model can be employed for computational and analytical frameworks.Weibull distribution is a numerical approach that is normally used by engineers for the analysis of brittle materials failure. Several research outcomes reveal that the Weibull distribution parameters are linked with the sizes and types of flaws55.The cumulative probability function of the Weibull distribution W(N) is used for the estimation and prediction of the residual compressive strength and relative strengths of the DPFRC subjected to elevated temperature as presented in Eq.  below55.P) is derived as presented in Eq. 13), γ an0 = 0 for the compressive strengths of the DPFRC under high temperature, then the survival probability function F(SP) can be presented as Eq. (Supposing the minimum concrete life Ζd as Eq. .14\documNow simplifying Eq.  by takin2) of the line can also be obtained and used to explain the accuracy of the Weibull distribution50.Lastly, Eq.  can be uEquation  depicts In the above Eq. , M repreDue to the fact that subjecting concrete to elevated temperature will increase its quasi-brittle nature and causes further variation in its strength, this study utilized the Weibull distribution function for the probabilistic modelling and reliability analysis of DPFRC containing silica fume under elevated temperatures.2). The plots of Ln(Ln(1/PJ) against Ln(Fc) is presented as Fig. J) against Ln(Rc) is given as Fig. 2s superior to 0.93. Hence, the residual compressive strength and relative strength of the DFPRC when exposed to elevated temperature followed the two-parameter Weibull distribution57. Hence the Weibull distribution function can be used for evaluation of the reliability or failure probability of the DPFRC under high temperatures. Shahraki, Hua54 have also found a similar result, where they reported the residual compressive strength of calcareous and siliceous concrete at temperature up to 1000 °C followed the two-parameter Weibull distribution function.The residual compressive strength (Fc) and relative strengths (Rc) of the DPFRC modified with silica fume exposed to elevated temperatures between 200 and 800 °C was analysed using Weibull distribution. The Weibull distribution parameters is presented in Table 60.th sample when the data is sorted in ascending orderThe Anderson–Darling test  and p-value were used to test if the residual compressive strength and residual strengths followed the normal probability distribution. The AD statistical values was calculated based on the following equations61 and summarized in Table P values for both the residual compressive strength and relative strength are very low (less than 0.05), hence the P-values of the AD statistic is not significant, hence the data does not follow the normal distribution. Therefore, Weibull distribution analysis which was used for the statistical analysis of the residual compressive strength and relative strength of the DPFRC subjected to high temperature is more appropriate.The AD statistical values for the residual and relative strengths were plotted as shown in Fig. The compressive strengths of the DPFRC under high temperature followed the two-parameter Weibull distribution as obtained in Sect. 3.2.3. Hence Weibull analysis was implemented for the estimation of the residual compressive strength and relative strengths of the DPFRC which corresponds to different survival probability (reliability). Equation  is used f represents probability of failure, Ζ and γ denotes the scale factor and shape factor respectively57.In the above equation, Fc and Rc represents the residual compressive strength and relative strength respectively, PP) is obtained using Eq. (Finally, the survival probability or design reliability (Ssing Eq. 21\documeTable The addition of DPF led to reduction in the residual compressive strength and relative strengths of the DPFRC, while the replacement of up to 10% cement with silica fume resulted to improvement in the residual compressive strength and relative strength of the DPFRC when subjected to a temperature up to 400 °C.The best validation performance for the model M-I is 0.000305017 at epoch 16 while for the model M-II is 0.0044732 at epoch 47.For neural networking model M-I, most of the predictive values carry errors in-between − 0.02 to + 0.02, which seems acceptable.The maximum predictive values by neural networking model M-II, carry error within bandwidth of − 0.05 to + 0.05For predictive neural model M-I, the regression is noticed R = 0.995 while for neural model M-II, the regression value is R = 0.989. Both depict the strong correlation between predicted and actual values.The multivariable regression models established for forecasting the performance of DPFRC exposed to high temperature have a very high statistical significance with a very good degree of correlation.The compressive strengths of the DPFRC concrete containing silica fume exposed to elevated temperature follows the two-parameter Weibull distribution functions.From the reliability analysis about 10% of the DFPRC mixes can survive exposure to elevated temperature up to 800 °C for 2 h and still achieve a compressive strength and relative strength up to 56.10 MPa and 149.51% respectively without failure.From the findings of the experimental results and analysis in this study. The following conclusions arises.For future works, the ANN techniques can be employed for the prediction of the mechanical properties and durability performance of PW concrete modified with GNP under normal environmental conditions. Additionally, the ANN techniques can be utilized for the prediction of the durability properties of the PW concrete modified with GNP subjected to other environmental conditions such as acid attack, salt or chloride attack, freeze and thaw.


Concrete is the most utilized construction material worldwide. In the marine environment, it is subject to chemical degradation through reactions with chloride (the most important ion), and sulfate and magnesium ions in seawater, and to biodeterioration resulting from biological  activities, principally acid production. These two types of corrosions are reviewed and the failure of attempts to predict the degree of deterioration resulting from each is noted. Chemical (abiotic) corrosion is greatest in the splash zone of coastal constructions, while phenomenological evidence suggests that biodeterioration is greatest in tidal zones. There have been no comparative experiments to determine the rates and types of microbial biofilm formation in these zones. Both chemical and microbiological concrete deteriorations are complex and have not been successfully modeled. The interaction between abiotic corrosion and biofilm formation is considered. EPS can maintain surface hydration, potentially reducing abiotic corrosion. The early marine biofilm contains relatively specific bacterial colonizers, including cyanobacteria and proteobacteria; these change over time, producing a generic concrete biofilm, but the adhesion of microorganisms to concrete in the oceans has been little investigated. The colonization of artificial reefs is briefly discussed. Concrete appears to be a relatively prescriptive substrate, with modifications necessary to increase colonization for the required goal of increasing biological diversity. Portland cement was invented in England in 1824; it consists of four main compounds: tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetra-calcium aluminoferrite. This innovation led to the subsequent developments that have made concrete, without doubt, the most important building material worldwide )Ref. , for exaCylindrotheca closterium, was able to liberate and utilize silicon from a cementitious mortar. The diatom utilized the Si to produce new frustule material during cell division. Diatoms have often been shown to deposit on immersed concrete; indeed, [Ref. , similar indeed,  suggesteNitrosopumilus sp., and iron-oxidizing bacteria within the Mariprofundus sp., as well as various heterotrophic bacteria and archaea at these tunnel sites. However, this microbial population will have included organisms from groundwater, as well as marine bacteria. In their later investigations [Ref.  reportedigations , they inigations . No specRef. ’s resultArtificial shoreline structures such as piers, reefs, seawalls, embankments, and jetties are common in developed coastal regions and serve as examples of intermittently immersed concrete that are also, incidentally, often steeply inclined. Obviously, the more steeply inclined the concrete, the less time it will spend covered in water. As noted in the section on chemical concrete corrosion, the splash zone is most affected by the corrosive action of seawater constituents plus oxygen from the atmosphere. However, simple observation indicates that this is not the zone most affected by biodeterioration .The intertidal zone shows deep pits and cracks in the concrete, associated with dark biofilms, while the splash zone above demonstrates black/green biofilms but without the intense corrosion of the intertidal zone. It is possible that the microbiological colonization has protected this area from the normally more intense chemical corrosion that occurs in the splash zone. Alternatively, it may be the greater wave impact at the wall base that is at least partially responsible for greater physical degradation.A similar, but less intense, situation can be seen in Ref.  found thLeptolyngbya, Anaerolineaceae, and Polynuceobacter. The concrete gate piers had the highest proportion of sulfate-reducing bacteria and were considered to be at the highest risk, although ammonia oxidizers were also predominant.Although not normally in contact with seawater, reservoirs are associated with various concrete structures such as walls, gate piers, and slopes that are only intermittently immersed in water and could give an indication of concrete colonizers on intermittently immersed structures. Ref.  studied Nitrosomonas, Nitrosopumilus, Nitrospirales, and Nitrospirota) were also detected at the site. Once leaked into the tunnel, the higher oxygen environment  would allow the production of inorganic nitrogen acids, encouraging concrete corrosion.A recent report on the presence of metagenomes associated with anammox (ammonium oxidizing) bacteria in water seepages on the concrete inner surface of the Subsea Oslofjord tunnel  is the fAlthough difficult to model, it is still fairly clear that certain ions in seawater lead to a reduction in the durability of concrete. These ions can be both utilized and produced by microorganisms and hence it is impossible to ignore their influence on so-called “abiotic” concrete corrosion in the oceans, although this will vary enormously, of course, depending on the microorganisms present and the surrounding physicochemical conditions. The effects of microbial adhesion and biofilm formation are themselves extremely variable, following the almost limitless variability of microorganisms. It is, however, possible to speculate on the possible interactions between chemical corrosion and microbial growth and activity.The bacterial biofilm, with its accompanying EPS formed on the concrete surface, can confer a degree of protection on the substratum. EPS can maintain the hydration of the underlying concrete, even when seawater is not covering it. Hence the desiccation associated with tidal and splash zones would not occur and abiotic corrosion would be reduced. It has also been suggested that biofilm can block the entry of aggressive sulfate and chloride ions into the concrete structure, thus enhancing its durability . BiofilmThe analysis of both the chemical and biological components of concrete biofilms from the marine environment would enable further potential interactions to be determined. Both qualitative and quantitative changes in cells and chemical compounds occur over the formation of the biofilm e.g., ,104,105),105104,1Although in use by mankind for thousands of years, artificial reefs are now being increasingly considered as possible answers to the diminishing biodiversity in coastal ecosystems ,110,111.Ref.  showed tAcinetobacter were enriched in 10-year-old samples, while Francisella was enriched in the one-year-old reef sediments. Unfortunately, the bacteria adhered to the concrete reefs were not sampled, although it might be assumed that some of these microorganisms would attach to buried parts of the reefs.Ref.  used metRef.  used metThe chemical corrosion of concrete in the marine environment is well understood in terms of the aggressive seawater ions and their interaction with concrete components. The long-term durability of coastal or deep-sea concrete structures, however, depends on a host of factors and it can be impossible to predict useful life simply based on the structural components. More detailed studies of different types of concrete and varied seawater constituents are necessary to enable useful predictions of concrete durability.Although, in principle, it is possible to understand the theoretical basis of chemical concrete corrosion, its complexity has so far prevented us from efficiently predicting this process in the different types and zones of seawater around the world.How much more difficult, then, is the understanding and prediction of microbial biodeterioration of concrete and the potential interactions between abiotic and microbial corrosion? Studies on “simple” colonization of concrete surfaces by marine microorganisms are hampered by a lack of suitable detection techniques. Nevertheless, new methods of study such as metagenomics and metabolomics are being developed and employed and will surely lead to a vast increase in our knowledge and understanding of the interactions between marine microorganisms and concrete. At the same time, surface protection methods, although not discussed in this article, are continually being developed. It is not necessary to understand how microbial cells attach to and attack concrete if effective methods of preventing this are available, although the purist will understand that a lack of knowledge of the reasons for any effective treatment can prejudice such treatment and its control. The acknowledgment that there is a need to conserve some concrete raw materials (such as sand) and that concrete itself is prejudicing the world’s biodiversity is already leading to changes in the way that we produce and monitor marine long-term structures. Concrete scientists and biologists will doubtless find themselves participating more frequently in future collaborations.


Due to its properties, pervious concrete is usually considered a material of choice for permeable surfaces. However, its permeability properties, as well as mechanical performance, depend on its effective porosity. In this paper, the Authors investigated the influence of material and technological factors on the selected properties of pervious concrete. A new method, based on the Vebe consistency test method, was developed to assess the vibration time required to reach a designed effective porosity of pervious concrete. Five classes of pervious concrete’s consistency measured by the modified vebe method were proposed, and the limiting values to determine optimum vibration time were indicated. A model of dependence between the porosity of pervious concrete, its consistency, and compaction time was proposed. It was found that for the assumed range of variability, compaction time and material composition significantly influence the porosity of pervious concrete, and, therefore, all properties of pervious concrete.  According to the “World Population Prospects 2019” report by the United Nations [Urbanization results in a successive reduction of biologically active areas, which are usually replaced by non-permeable surfaces. About 55% of rainwater from non-permeable surfaces is estimated to be discharged to sewage systems, and the other 30% evaporates. Consequently, only about 15% of the total rainfall soaks into the ground . For comReplacing natural vegetation areas with impervious land covers, such as conventional concrete and asphalt surfaces, contributes to water shortages during meteorological droughts and floodings during storm-type rains. The lack of water and air permeability of conventional pavement also disturbs the exchange of heat and moisture between soil and air, which causes the phenomenon of hot islands in urban areas and contributes to the deterioration of human health .Permeable pavements (PP) made of such materials as pervious concrete, porous asphalt, unit pavers, or granular materials are essential to reduce stormwater runoff, recharge groundwater supplies, and reduce the impact of the urban heat islands . Unlike Pervious concrete pavements can be cast in place or made from precast elements. Precasting allows better quality of pervious concrete elements due to the controlled environment in which they are made and the restricted quality control, which is often impossible when casting concrete in situ . PerviouThe pore structure is the crucial parameter affecting pervious concrete’s mechanical, hydrological, acoustic, and durability performance ,12. The 3 is much lower.Except for material factors describing the composition of pervious concrete, which contribute significantly to its performance, the applied compaction method and energy are critical in influencing the pore structure of pervious concrete ,21 and iIn situ pervious concrete is compacted mainly using hand steel rollers with low compaction energy directly after pouring . This tyUnlike conventional concrete, choosing the optimal parameters for the vibration process of pervious concrete is much more difficult since those are highly dependable on fresh mix workability. Vibrating fresh mix with high consistency for even a short time often leads to cement paste sagging and clogging the bottom of the sample, while mixes with lower consistency can be vibrated longer with no such risk. Compacting process parameters are often chosen via trial and error as there is a lack of standard test methods for measuring pervious concrete’s workability characteristics.2. Increasing vibrating energy further to 90 kNm/m2 resulted in a void ratio equal to 25% and compressive strength in the 15–22 MPa range, depending on the paste flow values. In their studies, Chindaprasirt et al. [2 as optimal in compacting pervious concrete. Yuan Jie Zhu et al. [Several articles regarding the pervious concrete compaction using the vibration method have been published—Chindaprasirt et al.  reportedt et al.  applied Suleiman et al.  used a tPervious concrete technology presents a different, environmentally friendly aspect of concrete technology . UsuallyThe experimental plan consisted of two stages: preliminary and in-depth studies . The preThe following constants were adopted at both stages of the research: water-to-cement ratio (mass), cement-to-sand ratio (mass), method of mixes and samples preparation, and methods of sample curing and testing.Three types of samples were used in the research: 100 × 100 × 100 mm cubic samples and ø150 × 300, ø150 × 150 mm cylindrical samples. The amount of samples in each of the tests varied from 1 to 3.2O5 solution was used as a dispersant, and 60 s of ultrasounds were applied to the cement’s dispersion before testing. The chemical composition analysis of cement was performed by X-ray fluorescence method using an Epsilon3x spectrometer . Cement’s specific surface was measured using Blaine’s method, and its specific gravity was determined by the pycnometer’s method. The sieving method determined the sand’s particle size distribution according to PN-EN 933-1 [Cement’s particle size distribution was measured by a laser diffraction method on the particle size analyzer LA-300 . A total of 0.4% PEN 933-1 .Samples were formed in one layer and compacted on a vibration table for a predefined period. The vibration frequency was 50 Hz, and the average vibration amplitude was 1.0 +/− 0.2 mm. During the compaction process, molds were fixed to the table. Before demolding, samples were stored for 24 h in the curing chamber . After demolding and prior to tests, samples were cured for 28 days in a curing chamber .The consistency of fresh mix was tested using a modified vebe method, similar to the ASTM C1170-06  test metForm the slump’s cone into three layers, each compacted by rodding 25 times;Raise the slump’s cone and spread the fresh mix evenly in the vebe container;Adjust the weighted plastic disc on the top of the fresh mix and start vibration;Measure the time until the cement paste fills the bottom of the transparent plastic disk or starts to sag downwards visibly.The modification allowed to replicate in near-to-surface layers similar compaction conditions to those occurring typically at the bottom of the mold where the wall effect and cement paste sagging clogging effect takes place. The test consisted of a few steps:Fresh mix porosity P (%) was calculated based on the difference between the measured pervious concrete’s density and the theoretical density of concrete mix with assumed 0% porosity by Equation (1).3.3.3.The fresh mix’s density was measured after compaction in 100 × 100 × 100 steel forms.Effective porosity was measured using the hydrostatic method. The technique consisted of several steps .First, samples were saturated to constant mass in water, and then the hydrostatic mass of the samples was measured. Afterward, samples were dried at a constant temperature of 105 °C for 24 h . Next, the samples’ dry mass was measured. Then, the sample was placed in a plastic bag and sealed in a vacuum using the Corelok device . A dry sample prepared that way was then placed in a hydrostatic balance. The collected results were used to calculate the porosity of the samples. The effective porosity PE (%) was calculated according to Equations (2)–(4).3.3.3.3.3.Cylindrical samples (ø150 × 300 mm) were used to determine the porosity’s distribution with a sample’s height. After 28 days of curing, samples were cut into three parts, each 95 mm long . The samCompressive strength was tested according to the PN-EN 12390-3  method uThe falling water head method was used to measure the permeability of pervious concrete on cylindrical samples with a diameter of 150 mm, and height of 150 mm using a self-made falling head system. The water permeability was defined by filtration coefficient k (mm/s) and calculated according to Equation (5).a—cross-sectional area of the cylindrical measuring tube, mm2.A—cross-sectional area of a cylindrical sample , mm2.L—cylindrical sample height, mm.t—time of water column fall from h1 to h2, s.h1—the initial height of the water column from which time measurement begins, mm.h2—the final height of the water column at which measurement ends, mm.1 height was located 100 mm from the sample’s upper surface, and the h2 height was located at the sample’s surface . Vebe time was defined as the time required for the transparent disc to be fully covered with cement paste or as the time required for cement paste to sag downwards visibly, whichever occurred first.Vebe time varied from 8.0 to 18.0 s for prepared concrete mixes and decreased linearly with increased cement paste content. The longest time was obtained for the mixture with the lowest mortar-to-coarse aggregate ratio .Vebe time of each mixture was within the range of quantification for this method, which suggested the assumed load was sufficient. After the modified vebe test, each sample showed significant signs of overcompaction—clogging.Fresh mixes’ porosity in the 11.5–19.5% range was observed. Porosity decreased linearly with an increase in vibration time. However, the significance of changes was different for each mix. The highest change in porosity was observed in the mix with the lowest mortar-to-aggregate ratio, where approximately a 12–13 percent decrease in porosity per 5 s of vibration was observed. Changes in the case of the two other mixes were significantly lower. Except for the outlier (porosity of 0.43 mortar to aggregate mix after 10 s of vibration), 1–9% decreases were noted per 5 s vibration .The lowest obtained porosities for each mix were similar regardless of the mortar-to-aggregate ratio and were approximately 11.5–12.5%. Samples with such low porosities were visibly clogged at the bottom and sides. Hence, 12.0% fresh mix porosity was adopted as the limit value, indicating overcompaction of pervious concrete for further research.Based on the detrimental effect of prolonged compaction on porosity characteristics of pervious concrete for the next research stage, the compaction time range was narrowed to a maximum of 15 s. For the assumed rheological properties of the cement mortar and superplasticizer content used in this study, it was assumed sufficient to study properties of pervious concrete, both in fresh and hardened state.Based on preliminary research, it was found that for the assumed range of variability of mortar content in pervious concrete, its composition and fluidity, compaction by vibration exceeding 15 s resulted in clogging concrete’s structure. As such, it was deemed unnecessary to include such a long compaction time in the next phase of the experiment, as the acquired material would no longer be able to perform the functions of a pervious concrete.Three batches of each mix were prepared during in-depth research, and the consistency of three samples from each batch was tested. Vebe time varied among mixtures, from 20.4 to 22.1 s in the case of the mix with the lowest mortar content, from 10.4 to 15.0 s with the 0.43 mortar to aggregate ratio, and from 5.1 to 7.8 s with the 0.45 mortar to aggregate ratio. Vebe time decreased linearly with the increase of mortar to aggregate ratio. For the mix with the highest amount of mortar, only 5.1–7.8 s was enough for the clogging effect to occur, unlike the mix with the least amount of mortar, which could be compacted for 20 s without the clogging effect.It was observed that depending on the amount of mortar in the composition of the mix, the rheological behavior of the fresh mix changed, and the test via the proposed modified vebe method allowed us to quantify those differences .The porosity characteristic of pervious concrete determines its properties, both mechanical and regarding water permeability. In the case of performed research, fresh mix porosity and effective porosity of hardened concrete were measured. It was found that depending on the mortar content in prepared mixes, as well as vibration time, both the total fresh mix porosity and effective porosity significantly changed . The HigFor each set of mixes characterized by the same mortar-to-aggregate ratio, a dependence between vibration time and change in porosity was observed . With anIn the case of compaction time’s influence on the porosity of fresh mixes of the same mortar-to-aggregate ratio, it was linearly dependent on the vibration time. This case was valid for all analyzed concrete mixes. The most substantial effect of compaction on the porosity characteristics was observed for mixes characterized with a mortar-to-aggregate ratio of 0.43, where the porosity of fresh mix changed from 16.68% to 10.57% with an increase in vibration time (from 5 to 15 s).For the same samples on which the porosity of fresh mix was tested, after 28 days, tests regarding the effective porosity of hardened pervious concrete were performed. This effort was made to establish a link between both those properties. It was found that the porosity of fresh mix was almost always lower than the effective porosity of hardened pervious concrete . This caCylindrical samples with a diameter of 150 mm and height of 300 mm were prepared to investigate the distribution of pores within different layers of compacted pervious concrete. After curing, samples were cut into three layers of the same height—upper, middle, and bottom  . Both coIn each tested series, the porosity varied between different layers of prepared samples. In most cases, the layer with the highest porosity was the bottom one—the one closest to the compaction table during sample preparation. The porosity of the upper part of the sample was the lowest one in all tested samples. The difference in effective porosity of different layers collected from the same sample was significant, reaching 8.57% (from 11.99% to 20.56% for different layers of a sample vibrated for 10 s and characterized by mortar-to-aggregate ratio of 0.45). Series with a mortar-to-aggregate ratio of 0.45 compacted for 15 s was characterized by the smallest difference in effective porosities between different layers. Although the entire sample was characterized with the lowest porosity of all tested samples (average of 11.72%), the difference in this property between layers reached only 3.58% (from 10.18% in the upper layer of the sample to 13.76 in the bottom layer).28-day compressive strength increased with the vibration time, although the significance of changes varied depending on the mortar-to-aggregate ratio. The lowest compressive strength of 19.9–31.0 MPa was observed for samples compacted for 5 s. Samples vibrated for 10 s had compressive strength in the range of 19.6–39.8 MPa and vibrated for 15 s in the range of 23.5–38.4 MPa . The sizThe compressive strength increased linearly with increased vibration time except for samples with the highest amount of mortar. The nonlinearity of the vibration time’s influence was observed in that case. However, due to the limited number of tested samples and the limitation of the experimental field, a linear function was used to show the trend.The pervious concrete with the highest amount of mortar and lowest porosity showed the best 28-day compressive strength. In that case, 5 s of vibration was sufficient to obtain a compressive strength of more than 30 MPa. For comparison, samples with the least amount of mortar reached compressive strength ranging from 21.0 MPa to 23.5 MPa. The obtained results showed that the mortar-to-aggregate ratio and the vibration time significantly impact the compressive strength of pervious concrete. However, the effect of mortar content in the mix was significantly stronger than vibration time.The modulus of elasticity ranged from 19.1 to 30.6 GPa—the highest results were obtained for samples with the highest mortar-to-aggregate ratio with the lowest porosity. The results of samples with 0.41 and 0.43 mortar-to-aggregate ratios were similar regardless of the vibration time. The modulus of elasticity increased liner with the vibration time .The water permeability coefficient (k) varied from 1.1 to 5.5 mm/s. It was significantly influenced by vibration time and mortar-to-aggregate ratio . SamplesThe authors proposed a modified vebe method to quantify the vibration time needed to overcompact the pervious concrete sample. Knowing such time would help to determine the optimal time of vibration. It could be useful in adjusting the rheological parameters of a fresh mix by, e.g., the addition of admixtures. The method could also be used in everyday quality control of pervious concrete.The Vebe method was used earlier in the studies ,42,43 toIn the standardized vebe method,  tested sThe presented method allowed us to quantify the consistency of pervious concrete mixes with mortar-to-aggregate ratio varying from 0.41 to 0.43. Recorded vebe times ranged widely, from 5.1 to 22.1 s, which made it possible to identify even slight differences between rheological parameters of examined mixes with the same mortar content.The average fresh mix porosity of samples compacted for a longer time than determined by the modified vebe method was lower than 13.0% , which wThe results indicate that pervious concrete consistency measured by the modified vebe method should be specified in classes rather than target values. Based on the results rounded up to the nearest unity, authors suggest five classes of pervious concrete’s consistency measured by the described method : PV4  of the mixture on the vebe time  and the vibration time  of the mixture was obtained.Based on the results, a numerical model was created using a multivariate regression method. As a result of calculations, the regression Equation (6) describing the dependence of the porosity , the Authors suggest initially describing concrete’s composition as a set of mass ratios between different components of the concrete mix—depending on the type of pervious concrete by either mortar-to-aggregate ratio and cement-to-sand ratio, or by cement paste-to-aggregate in the case of composition without fine aggregate. The water-to-cement ratio additionally describes concrete. All those proportions accurately describe every pervious concrete mix—its volume depends on its final porosity, properties and amount of components of the mix, and compaction characteristics. Due to this, concrete mix with the same proportion between components and a difference in the porosity can be characterized by a different composition per volume .3 changed depending on its porosity, resulting in different masses of, for example, cement in the unit of volume.In the case of performed research, the composition of the concrete mix depended on the proportions between different components of the mix and the porosity of the fresh concrete mix. For concrete mixes of the same ratios between its components, the overall composition of fresh mix per 1 mProperties of pervious concrete, mainly compressive strength, permeability coefficient, and modulus of elasticity, depend on the effective porosity of pervious concrete;The composition of the pervious concrete mix depends on the proportions between its different components and porosity—concrete of the same ratios between different components can be characterized by different overall composition due to differences in the porosity of fresh mix;The effective porosity of pervious concrete and the porosity of fresh concrete mix depends on the material composition of pervious concrete (mortar-to-aggregate ratio) and compaction time;The optimal compaction time to acquire designed effective porosity changes along with the material composition of pervious concrete;An increase in the content of mortar in the composition of pervious concrete results in a shortening of compaction time required to reach the designed effective porosity;The modified vebe method proposed by authors allowed to quantify the consistency of pervious concrete mixes with mortar-to-aggregate ratio varying from 0.41 to 0.43. The proposed method made it possible to identify even slight differences between the rheological parameters of examined mixes with the same mortar content;Authors suggest five classes of pervious concrete’s consistency measured by the modified vebe method: PV4 (1–4 s), PV3 (5–9 s), PV2 (10–16 s), PV1 (17–25 s), PV0 (>25 s). The suggested consistency classes are justified as analogous to, e.g., slump classes for conventional concrete and could help determine the optimal vibration time;A numerical model proposed by authors allows us to predict the desirable porosity of fresh mix based on the modified vebe time and vibration time on the vibration table.Using pervious concrete as a pavement material positively affects human comfort and water management issues regarding water retention, storage and drainage, and purification. Elements constructed with pervious concrete are also sound absorbers and reduce the heat island phenomenon in urban areas. However, to properly design properties of concrete of that type, its composition and preparation method must be appropriately selected to reach its designed porosity. Based on the conducted research, several conclusions can be made: