Polypropylene Fiber Reinforced Concrete Research Articles

Utilizing bio-based and industrial waste aggregates to improve mechanical properties and thermal insulation in lightweight foamed macro polypropylene fibre-reinforced concrete

This research intends to examine the potential of incorporating waste materials in place of coarse aggregates to augment the mechanical characteristics and thermal insulation of lightweight foamed concrete (LWFC), along with the inclusion of polypropylene (PP) fibres. The PP fibre exhibits excellent tensile strength and enhancement on thermal insulation properties of cementitious materials. In this study, eco-friendly bio-based oil palm shell (OPS) and robust solid polyurethane (SPU) aggregates derived from industrial waste were utilized as substitutes for conventional aggregates. Additionally, silica fume was partially incorporated as supplementary cementitious materials. The addition of PP fibre impacted the workability of the LWFC with the inverted slump value decreased by 1.7 %–17.5 %. The inclusion of PP fibre proportion increased from 0 % to 0.5 % revealed a positive result in mechanical properties and thermal insulation performance. The OPSSPU/0.5 showed the significantly increment of 40.4 % compressive strength, 102.9 % of splitting tensile strength, and 70.8 % flexural strength, respectively. The optimum result was obtained in the OPSSPU/0.5 mixture, which exhibited 3.74 MPa residual compressive strength. Furthermore, utilizing PP fibres brought about a significant reduction in thermal conductivity in the environmentally sustainable LWFC, leading to improvements ranging from 0.2 % to 16.3 % when compared to the control composition. Thus, these findings are essential for encouraging the adoption of such practices in the construction industry and contributing to the reduction of environmental impacts associated with sustainable concrete production.

Study on the Effect of Post-Freezing Mechanical Properties of Polypropylene Fibre Concrete Based on BAS-BPNN

An indoor accelerated freezing and thawing test of polypropylene fibre-reinforced concrete in chloride and sulphate environments was conducted using the “fast-freezing method” with the objective of investigating the damage law of the post-freezing mechanical properties of hydraulic concrete structures and studying the effects of different mixing amounts of polypropylene fibres on the mechanical properties of concrete. Furthermore, in order to reduce the cost of concrete tests and shorten the time required for conducting concrete tests, a backpropagation neural network based on a Beetle Antenna Search algorithm (BAS-BPNN) was established to simulate and predict the mechanical properties of polypropylene fibre-reinforced concrete. The accuracy of the model was verified. The results indicate that the order of improvement in the macro-physical properties of concrete due to fibre doping is as follows: PPF1.2 exhibited the greatest improvement in macro-physical properties of concrete, followed by PPF0.9, PPF1.5, PPF0.6, and PC. When the freezing and thawing medium and the number of cycles are identical, all four assessment indexes (R2, RMSE, SI, MAPE) demonstrate that the four groups of polypropylene fibre concrete exhibit superior performance to the control group of ordinary concrete. This indicates that polypropylene fibre can enhance the mechanical properties and freezing resistance of the concrete matrix, delay the process of freezing and thawing damage to the matrix, and extend the lifespan of the matrix, yet cannot prevent the ultimate failure of the matrix. The application of intelligent algorithms to optimise the parameters of an artificial neural network model can enhance its capacity to generalise and predict the mechanical properties of concrete. In terms of the coefficient of determination (R2), the Beetle Antenna Search algorithm (0.9782) outperforms the Particle Swarm Optimization (PSO; 0.9676), the Genetic Algorithm (GA; 0.9645), and the backpropagation neural network (BPNN; 0.9460). The improved backpropagation neural network based on the Beetle Antenna Search algorithm not only avoids the trap of local optimality but also improves the model accuracy while further accelerating the convergence speed. This approach can address the complexity, non-linearity, and modelling difficulties encountered during the freezing process of concrete. Moreover, it offers relatively accurate prediction outcomes at a reduced cost in comparison to traditional experimental methodologies.

Study on early-age cracking resistance of multi-scale polypropylene fiber reinforced concrete in restrained ring tests

The primary cause of early-age cracking is high tensile stress resulting from restrained shrinkage of concrete structures. This study examined the shrinkage performance of polypropylene fiber reinforced concrete (PFRC) through restrained ring and free shrinkage tests. The impact of polypropylene fiber on shrinkage deformation and restrained shrinkage stress of concrete was analyzed. Furthermore, the mechanism of multi-scale polypropylene fiber to improve the crack resistance of PFRC was discussed. Test results demonstrated that adding polypropylene fiber to concrete significantly reduced the possibility of early cracking in concrete matrix. Plain concrete (A0) showed the highest potential for early-age cracking. At 28 days of age, the cracking risk factor of single-doped, double-doped, multi-doped polypropylene fiber reinforced concrete (A1, A2, and A3) was 0.851, 0.793, and 0.665, which decreased by 7.1%, 13.43%, and 27.4% compared with A0, respectively, suggesting the effect was better positive in reducing the crack risk when multi-scale polypropylene fiber hybridized.

Study on the tensile and compressive mechanical properties of multi-scale fiber-reinforced concrete: Laboratory test and mesoscopic numerical simulation

To investigate the tensile and compressive mechanical properties of multi-scale polypropylene fiber-reinforced concrete (PFRC), two-dimensional microscopic finite element models of PFRC were established, and their reliability was verified using laboratory test results. The failure development process and tensile and compressive behaviors of multi-scale PFRC were simulated. In addition, the influence of the length and dosage of polypropylene fibers (PFs) on the mechanical properties of concrete was investigated using mesoscopic numerical simulations. The numerical models established in this study fill the gap in existing research by revealing both the distribution of multi-scale PFs and the true shape of the aggregates. The results predicted by the proposed numerical models were in good agreement with the experimental results. Moreover, the ideal PF length was 30 or 40 mm, and the optimum fiber dosages of two fine polypropylene fibers (FPF1, FPF2) and coarse polypropylene fiber (CPF) were 0.6 kg/m³, 0.6 kg/m³, and 4.8 kg/m³, respectively. This study reveals the influence of parameters such as the length and dosage of multi-scale PFs on the mechanical properties of concrete, providing a reference for engineering applications.

Experimental study on the effect of polypropylene fiber on compressive strength and fracture properties of high-strength concrete after elevated temperatures

Polypropylene fibers improve the toughness of concrete and reduce the susceptibility of high-strength concrete (HSC) to high temperature spalling. And the mechanical properties of polypropylene fiber reinforced concrete (PFRC) become important after exposure to high temperatures, especially in situations related to engineering uses or repairing concrete structures damaged by fire. This paper presents an experimental study on the compressive strength and fracture properties of PFRC experiencing different temperatures with different fiber contents and lengths. It was shown that the fracture path of concrete becomes longer after experiencing high temperatures. The rate of debonding of mortar and coarse aggregate increases with the temperature rising. The compressive strength of concrete and the peak load and fracture energy of three-point bending beams were both increased by the addition of polypropylene fibers at room temperature, and the compressive strength increased with the increase of fiber content. The addition of polypropylene fibers is able to increase the compressive strength of concrete compared to the control group at experiencing temperatures less than 300 oC. The peak forces of the three-point bending of the concrete beams all show a decreasing trend with the increase in the experienced temperature. The initial slopes of the rising part of the force-loading point displacement and force-crack mouth opening displacement (CMOD) curves all decrease with increasing of temperature, and curves gradually become slower. Addition of polypropylene fibers decreases the peak force of concrete after high temperature. There is no significant pattern in the effect of polypropylene fiber content and length on the peak force and fracture energy of concrete three-point bending beams.

Study on bending failure and crack characteristics in ductile fiber‐reinforced concrete beams

AbstractIn this study, we designed six polypropylene fiber‐reinforced concrete (PP‐FRC) beams and three reinforced concrete (RC) beams for experimental studies. Then, we analyzed the effects of incorporating PP fibers on the cracking performance of PP‐FRC beams from the perspectives of load‐displacement response, crack distribution, crack depth, crack width, crack spacing, and deformation coordination. The research results showed that the cracking load and number of cracks were positively correlated with the volume ratio of PP fibers, while the maximum crack width, average crack spacing, and average crack depth were negatively correlated with the volume ratio of PP fibers. Due to the bridging effect of fibers, the PP‐FRC beam body and reinforcement could deform in a coordinated manner within a specific loading range after cracking, which increased the deformation coordination ability between the body and reinforcement. In this study, the cracking mechanism of PP‐FRC beams was investigated. Firstly, the formula for calculating the cracking moment of PP‐FRC beams was derived from the perspective of equivalent bending tensile strength. Then, based on the fiber bridging law and the bond strength between PP‐FRC and reinforcement, theoretical formulas were proposed to predict the average crack spacing and maximum crack width of PP‐FRC beams. Finally, through comparison, it was found that the proposed formulas could be used for characteristic crack prediction.

Experimental Study on the Mechanical Properties of Hybrid Basalt-Polypropylene Fibre-Reinforced Gangue Concrete

Incomplete data indicate that coal gangue is accumulated in China, with over 2000 gangue hills covering an area exceeding 200,000 mu and an annual growth rate surpassing 800 million tons. This accumulation not only signifies a substantial waste of resources but also poses a significant danger to the environment. Utilizing coal gangue as an aggregate in the production of coal-gangue concrete offers an effective avenue for coal-gangue recycling. However, compared with ordinary concrete, the strength and ductility of coal-gangue concrete require enhancement. Due to coal-gangue concrete having higher brittleness and lower deformation resistance than ordinary concrete, basalt fibre (BF) is a green, high-performance fibre that exhibits excellent bonding properties with cement-based materials, and polypropylene fibre (PF) is a flexible fibre with high deformability; thus, we determine if adding BF and PF to coal-gangue concrete can enhance its ductility and strength. In this paper, the stress–strain curve trends of different hybrid basalt–polypropylene fibre-reinforced coal-gangue concrete (HBPRGC) specimens under uniaxial compression are studied when the matrix strengths are C20 and C30. The effects of BF and PF on the mechanical and energy conversion behaviours of coal-gangue concrete are analysed. The results show that the ductile deformation of coal-gangue concrete can be markedly enhanced at a 0.1% hybrid-fibre volume content; HBPRGC-20-0.1 and HBPRGC-30-0.1 have elevations of 53.66% and 51.45% in total strain energy and 54.11% and 50% in dissipative energy, respectively. And HBPRGC-20-0.2 and HBPRGC-30-0.2 have elevations of 31.95% and 30.32% in total strain energy and −3.46% and 28.71% in dissipative energy, respectively. With hybrid-fibre volume content increased, the elastic modulus, the total strain energy, and the dissipative energy all show a downward trend. Therefore, 0.1% seems to be the optimum hybrid-fibre volume content for well-enhancing the ductility and strength of coal-gangue concrete. Finally, the damage evolution and deformation trends of coal-gangue concrete doped with fibre under uniaxial action are studied theoretically, and the constitutive model and damage evolution equation of HBPRGC are established based on Weibull theory The model and the equation are in good agreement with the experimental results.

Finite Element Modelling of Polypropylene Fibre Reinforced Concrete Beams Reinforced with Steel under Bending

Application of the fibre-reinforced concrete has manifested a wider acceptability over time for its contribution towards significantly improving the flexural performance of structural members. A lot of work has been done to understand the influence of fibres on the mechanical and structural behaviour of reinforced concrete. Towards this end, several researchers have experimentally investigated the residual flexural strength to characterize the fibre-reinforced concrete. The number of influencing parameters to be investigated through experiments is mostly limited because of the time and cost implications. Consequently, validation of the experimental investigations through analytical models and further utilizing these models to study the behaviour in greater detail is a viable option for researchers. As part of this work, an analytical investigation has been performed to investigate the performance of full-scale polypropylene fibre-reinforced concrete beams. The models have been validated through comparison with the observed performance during an experimental investigation where tests on twelve full-scale FRC beams were performed. Three-dimensional finite element models of the beams under 4-point loading were prepared and the post-cracking flexural performance of FRC beams has been investigated by varying the dosage of polypropylene fibres obtained from shredding medical face masks.

Application of artificial intelligence in predicting the residual mechanical properties of fiber reinforced concrete (FRC) after high temperatures

The practical application of Artificial Intelligence (AI) approaches in estimating the mechanical properties of fiber-reinforced concrete (FRC) subjected to high temperatures was initiated by developing a dataset including concrete mixtures, geometrical and mechanical properties of fiber, and temperatures. The dataset contains compressive strength, tensile strength, and modulus of elasticity of concrete with two distinct types of fiber, i.e., steel and polypropylene with an extensive range of temperatures from 100 to 1200 ℃. The dataset determined the gaps in the literature and showed FRC with high fiber aspect ratios and higher content of fiber (>0.8%) are not studied enough. The AI-based models showed that steel fiber-reinforced concrete (SFRC) has higher residual compressive strength compared with polypropylene fiber-reinforced concrete (PFRC). An increase in steel fiber diameter and length resulted in a higher compressive strength ratio at all temperatures. Moreover, higher PP fibers content and longer PP fibers decrease the rate of tensile strength degradation. A large probabilistic analysis was performed, and it showed that the failure probability (Pf) for PFRC is independent of W/B ratios and is almost 50%;. In contrast, for SFRC, W/B ratios between 0.4 to 0.5 have lower failure probability in comparison with other W/B ratios. Moreover, Pf for both fibers at a W/B ratio of 0.5 is almost independent of fiber content. Furthermore, the critical temperature resulting in failure (defined as the residual strength ratio less than 0.5) for SFRC and PFRC is 550 ℃ and 430 ℃, respectively.

Effect of free and embedded polypropylene fibres recovered from concrete recycling on the properties of new concrete

This study aims at investigating the effect of incorporating different quantities of polypropylene fibres recovered during concrete recycling or embedded in recycled aggregates on the mechanical properties of new polypropylene fibre-reinforced concrete (PPFRC). Both recovered fibre (at replacement ratios of 0 %, 10 %, 30 % and 100 %) and recycled coarse aggregate (0 %, 100 %) were used in new concrete. Polypropylene fibre contents of 3 and 9 kg/m3 (0.33 % and 1.0 % by volume, respectively) were chosen for all concretes. The properties of recovered and virgin fibres were tested to determine the effect of recycling on fibre properties. The compressive strength, elastic modulus and stress–strain behaviour in compression were tested and a constitutive model was developed to fit the stress–strain behaviour of the PPFRC with mixed recovered and virgin fibres. The residual tensile strength was also tested for concretes with recovered fibres and fibres embedded in recycled aggregate. The results show that mixing of recovered and virgin fibres is feasible without significant effect on mechanical properties of concrete. At the same time, inclusion of recycled coarse aggregate from PPFRC recycling contributes to residual tensile strength through the presence of fibres embedded in the aggregate.

Mesoscale modeling of polypropylene fiber reinforced concrete under split tension using discrete element method

This study is proposed to determine the effectiveness of the discrete element method (DEM) in predicting the tensile properties of polypropylene fiber-reinforced concrete (PFRC). To calibrate and validate the proposed PFRC simulation model, splitting tensile tests were performed on limestone (granite)-polypropylene fiber reinforced mortar (PFRM) hybrid samples to investigate the effects of polypropylene fiber (PF) contents and aggregate types on the tensile properties of the interfacial transition zone (ITZ). The test improved the particle contact mode in the PFRC discrete element model. Based on DEM software (PFC3D), a multi-phase microscopic discrete element model was created, and the tensile properties of PFRC were predicted by simulating a splitting tensile test. The simulation results revealed that the proposed model could be more efficient in predicting the splitting tensile responses of PFRC. The improved flat joint-softening contact model is more accurate and stable for the bridging effect simulation of PF after concrete cracking.

Post-Cracking Properties of Concrete Reinforced with Polypropylene Fibers through the Barcelona Test.

The Barcelona method was developed as an alternative to other tests for assessing the post-cracking behavior of fiber-reinforced concrete, with the main advantage being that it uses significantly smaller specimens compared to other methods. For this reason, it can provide a solution for characterizing concrete in hard-to-reach constructions such as roads and tunnels. On the other hand, polypropylene (PP) fibers have gained increased attention in recent years within the scientific community due to their high tensile strength and cost-effectiveness. This research aimed to understand the influence of PP fiber volume, slenderness (l/d), and reinforcement index on post-cracking properties of concrete, including toughness and residual strength (f_res), using the Barcelona method. Three fiber volumes, 0.4%, 0.8%, and 1.2%, and three slenderness ratios, 46.5, 58.1, and 69.8, were employed in normal-strength concrete. In addition to the reference mixture without fibers, 10 mixtures were prepared with 10 specimens each, resulting in a total of 100 specimens. Pearson's hypothesis test was employed to determine the existence of correlations between variables, followed by scatter plots to generate predictive equations between post-cracking properties and fiber attributes. The results indicated no direct correlation between fiber slenderness and post-cracking properties. Regarding fiber volume, there was a correlation with residual strength but not with toughness. However, the combined effect of volume and slenderness, the reinforcement index, correlates with the post-cracking properties of concrete. Finally, four predictive equations for toughness and residual strength were derived based on the reinforcement index. These equations can prove valuable for designing structures made of polypropylene fiber-reinforced concrete.

FLEXURAL PROPERTIES OF POLYPROPYLENE FIBER REINFORCED CONCRETE CONTAINING FLY ASH FOR NORMAL CONCRETE PAVEMENT

The purpose of this study is to examine the applicability and efficiency of polypropylene fiber reinforced concrete (PPFRC) mixed with fly ash for new concrete pavements. In the field of concrete pavements, many researchers focused on steel fiber reinforced concrete pavements to improve the mechanical properties. Polypropylene fibers can also improve the flexural toughness and the residual flexural strength. However, in the construction sector, a large amount of CO2 is emitted during the production of cement. The reduction of CO2 emissions is an urgent task in the world. The CO2 emissions can be reduced by replacing a part of such cement with fly ash as one alternative material. In this study, four-point flexural tests were carried out on PPFRC with 1.0 vol.% and 1.3 vol.% of polypropylene fiber. Furthermore, the pavement thickness and the reduction of CO2 emissions were calculated based on the test results to examine the effect of added fiber and fly ash replacement. Consequently, the PPFRC pavement reduces the thickness by about 18% and reduces the CO2 emissions by about 30% in comparison with normal concrete pavements.

Experimental and Simulation Study of the Fracture Instability Behavior in Polypropylene Fiber-Reinforced Concrete.

This study investigated the fracture characteristics of plain concrete and polypropylene fiber-reinforced concrete (PFRC) using pre-notched three-point bending beam tests with the digital speckle correlation method (DSCM). Then, the fracture instability behavior of the two types of beams was simulated in finite elements based on the plastic damage model and the cohesion model, for which the applicability was assessed. Furthermore, the stability of the Big Gang Mountain Dam made from plain concrete or PFRC subjected to the earth-quake loading was simulated with the plastic damage model. The results show that the limiting length of the non-local deformation zone can be used as an indicator of instability damage in a concrete structure. The simulation results of the plastic damage model agreed well with the local deformation in the pre-notched three-point bending beam test obtained from the DSCM. The plastic damage model was found to be capable of describing the residual strength phenomenon, which the cohesive model was not capable of. The damage evolution regions of the PFRC dam are strictly constrained in some regions without the occurrence of the local deformation band across the dam, and PFRC can dramatically reduce the failure risk under earthquake loading. The numerical solution proves that PFRC is an advisable material for avoiding failure in concrete dams.

Bond durability performance of sand-coated BFRP bars in high-strength fiber reinforced concrete

The ever-increasing utilization of fiber-reinforced polymer (FRP) bars has led to a surge in research regarding their bonding properties with concrete. In this study, the bond durability behavior between high-strength fiber-reinforced concrete (FRC) and sand-coated basalt FRP (BFRP) bars was examined under three different environmental conditions including immersion in seawater solution at 50 °C for 3, 6, and 9 months, immersion in the sulfuric acid solution for 3, 6, and 9 months with an ambient temperature range of 20 to 30 °C, and exposure to 270 freeze–thaw cycles. A total of 60 pull-out samples were prepared using either basalt (B) fibers or polypropylene (PP) fibers. Plain concrete pull-out samples were served as controls. Test results revealed that all exposures have degraded the bond, leading to pull-out failure in all of the specimens. Exposure to 50 °C seawater was found to cause the most significant degradation. However, the use of basalt fibers helped to mitigate the loss of bond strength in the specimens when compared to plain concrete specimens. For example, after 3, 6, and 9 months of exposure to 50 °C seawater, bond strength retentions of 73.58%, 56.04%, and 34.47% were observed for basalt FRC (BFRC) specimens, compared to 39.64%, 49.37%, and 29.61% for plain concrete specimens. On the other hand, a lower retention in bond strength of 16.28% was recorded for polypropylene FRC (PPFRC) specimens at 9 months of exposure to 50 °C seawater. The bond stress-slip relationship of the tested bars was accurately predicted using two calibrated analytical models: the Eligehausen, Popov, and Bertero (BPE) model and the Cosenza, Manfredi, and Realfonzo (CMR) model. Notably, both models showed a strong correlation with the observed bond stress-slip relationships in the experiments.

Applicability of fractal models for characterising pore structure of hybrid basalt–polypropylene fibre-reinforced concrete

Abstract The pore-structure characteristics of hybrid basalt–polypropylene fibre-reinforced concrete were investigated by using mercury intrusion porosimetry. The applicability of various fractal models in characterising the HBPRC pore structure was compared. The results show that the types and content of fibres show different influences on the cumulative pore volume and fractal characteristics of hybrid basalt-polypropylene fibre-reinforced concrete. Compared with pore-volume and solid mass, the fractal characteristics of pore surface area of hybrid basalt-polypropylene fibre-reinforced concrete is more significant. Furthermore, the pore-surface fractal model that established based on the energy conservation relationship during mercury intrusion is more accurate and effective for the characterization of fractal dimension of hybrid basalt-polypropylene fibre-reinforced concrete. The research results can provide important theoretical guidance for the study of pore structure and fractal characteristics of fibre-reinforced concrete.

Sustainable Solution for Disaster Management of Cement Concrete Constructions

This research aims at quantifying the effect of Polypropylene fibres in Pavement quality concrete mixes. Rigid pavement construction is based on conventional cement concrete. It is a well-known fact that conventional concrete is comparatively stronger in compression and weaker in tension. It also shows the properties like brittle material and it results in the development of cracks. In this laboratory investigation, different percentages of steel and polypropylene fibres were used to check their effect on the compressive and flexural strength of concrete mixes. The final combination was named SPFRC i.e., steel polypropylene fibre-reinforced concrete. Tests were conducted with different percentages of steel fibres and polypropylene fibres. IS:10262 [1] guidelines were followed for the design of the concrete mix. The outcome shows that there is a marginal increase in compressive strength but a considerable increase in the flexural strength of concrete.

Destructive and Non-Destructive Analysis of Polypropylene Fibre Reinforced Concrete

Plain Cement Concrete (PCC) is brittle and has low tensile strength. The brittleness can be avoided by adding fibre. Fibre-reinforced concrete (FRC) is concrete containing fibrous material spread across concrete, which increases its structural integrity. Addition of fibres to concrete makes it an isotropic material and converts its brittle behaviour to ductile behaviour. In the Fibre Reinforced Concrete, polypropylene fibres are rationally combined to produce a cementitious composite that derives benefits from each of the individual fibres and exhibits a synergistic response. Based on I.S. Code method of mix design, proportion of different ingredients was obtained to get M30 grade concrete. Samples were prepared with varying the volume fraction of fibres from 0.50% to 2.50%. The optimum dosage is determined from among the above mixes. The result shows that optimum dosage is obtained at 1.50% addition of fibre. The main aim of the present experimental investigation was to use different volume fractions of polypropylene fibres to produce FRC and thus to evaluate its performance by comparing Destructive tests such as compression, tension, flexure and Non-destructive tests such as Rebound Hammer, Ultrasonic Pulse Velocity and Durability Parameters such as Water Absorption, Sorpitivity etc., .From the results obtained fibre reinforced concrete shows higher values than normal concrete under Compression, Split Tensile and Flexural Strength. The water absorption is reduced for FRC compared to Normal Concrete.

Prediction of rheological parameters of 3D printed polypropylene fiber-reinforced concrete (3DP-PPRC) by machine learning

This paper proposes a machine learning (ML) model to predict the 3D printed polypropylene fiber-reinforced concrete (3DP-PPRC) rheological properties, in which dynamic yield stress (DYS) plays a vital role. ICAR rheometer is used to measure the yield stress of the concrete mixture, where 41 mixtures were used to compile the data. In this research, four machine-learning models have been used to predict the DYS of the 3DP-PPRC, accounting for different water binder ratios (W/B) and polypropylene (PP) fiber content. The code has been generated in Python scripts. Several ML models such as random forest (RF), support vector machine (SVM), extreme gradient boosting (XGBoost), and light gradient boosting machine (LightGBM) have been used to predict the DYS, considering 80% and 20% data for training and testing, respectively while the model’s accuracy, MSE, RMSE, MAPE, and R2 were also calculated for 3DP-PPRC. The influence of each rheological parameter in the ML-based of 3DP-PPRC, Shapley additive explanations (SHAP) are also accompanied. The outcomes proved that utilizing an ML model to estimate the yield stress of 3DP-PPRC using PP fiber is a dominant approach.

Behavior of Magnetic Self-Compacting Polypropylene Fiber-Reinforced Concrete

This paper aims to produce a new concrete that combines the benefits of self-compacting concrete (SCC), polypropylene fiber (PPF), and magnetic water (MW). Slump flow, L-box, V-funnel, compressive strength, split tensile strength, and flexural strength approaches were performed to investigate the fresh properties and mechanical behavior of concrete. Various percentages (0.4%–1.2%) of self-compacted agent (SCA) and different percentages (0%–0.5%) of PPF by weight of cement were adopted. The results showed that 0.8% SCA magnetized concrete had very similar fresh properties to 1.2% SCA nonmagnetized concrete. This led the author to believe that using MW as an alternative to ordinary tap water in the manufacture of SCC has promising benefits, the most important of which is reducing the used dosage of SCA by approximately 33.3% (from 1.2% to 0.8%), resulting in a lower cost of production of such type of concrete while retaining the same workability. The optimum percentage of PPF to be used in magnetic and nonmagnetic self-compacting concrete is 0.35%.