Fiber Reinforced Lightweight Concrete Research Articles

Hybrid Fiber Reinforced Lightweight Concrete: Vegetal and Metalized Plastic Waste Fiber Synergy and Pull-Out Behavior

Abstract Using one or more fibers in concrete is called “hybridization.” Although single-fiber concrete offers excellent performance, concrete reinforced with hybrid fibers gains speed as the synergy between the fibers results in amplified performance. This experimental work reflects the effects of incorporating 1, 2, and 3 % untreated singular and hybrid fibers on the physical and mechanical properties of lightweight concrete (LC) at 3, 28, and 90 days. Six mixture types were used: control LC, LC containing metalized plastic waste fibers (MPWFs), LC containing date palm fibers (DPFs), LC containing sisal fibers (SFs), LC with MPWFs and DPFs (Hybrid A), and LC with MPWFs and SFs (Hybrid B). In the fresh state, fiber introduction affected all mixes’ workability and wet density, and the reduction in slump and wet density was proportional to the fiber dose. However, in the hardened state, the results indicate that compressive strength (CS) and modulus of elasticity (MOE) decreased for LC containing only plastic or SFs. However, these properties increased slightly over the long term for blends containing 1 % DPF. Excepting mixtures containing MPWFs, fiber introduction improved flexural strength (FS) for all blends containing 1 % and 2 % fibers at 28 and 90 days. The most significant gains in FS were 8 % and 4 % at 28 and 90 days, respectively, for samples containing 1 % DPF. Nevertheless, fiber hybridization improved these mechanical properties and created a positive synergy in long-term bending. At 1 % fiber dosage, CS, MOE, and FS increased respectively by 3.05, 3.10, and 8 % for Hybrid A compared with the control LC. Pull-out testing provides the best means to understand typical failure modes and assess maximum tensile strength. Consequently, microstructural analysis enabled us to examine the bonding quality at the fiber-matrix interface.

Compressive Properties of Basalt Fibers and Polypropylene Fiber-Reinforced Lightweight Concrete.

With the development of high-rise and large-scale modern structures, traditional concrete has become a design limitation due to its excessive dead weight. High-strength lightweight concrete is being emphasized. Lightweight concrete has low density and the characteristics of a brittle material. This is an important factor affecting the strength and ductility of the lightweight concrete. To improve these shortcomings and proffer solutions, a three-phase composite lightweight concrete was prepared using a combination of tumbling and molding methods. This paper investigates the various influencing factors such as the stacking volume fraction of GFR-EMS, the type of fiber, and the content and length of fiber in the matrix. Studies have shown that the addition of fibers significantly increases the compressive strength of the concrete. The compressive strength of concrete with a 12 mm basalt fiber (BF) (1.5%) admixture is 9.08 MPa, which is 62.43% higher than that of concrete without the fiber admixture. The compressive strength was increased by 27.53 and 21.88% compared to concrete containing 3 mm BF (1.5%) and 0.5% BF (12 mm), respectively. Fibers can fill the pore defects within the matrix. Mutually overlapping fibers easily form a network structure to improve the bond between the cement matrix and the aggregate particles. The compressive strength of lightweight concrete with the addition of BF was 16.71% higher than that with the addition of polypropylene fiber (PPF) with the same length and content of fibers. BF has been shown to be more effective in improving the mechanical properties of concrete. In this work, the compressive mechanism and optimum preparation parameters of a three-phase composite lightweight concrete were analyzed through compression tests. This provides some insights into the development of lightweight concrete.

A novel Ductile Lightweight Fiber-Reinforced Concrete (DLFC) infill for seismic-prone zones: Experimental and numerical investigations

In urban construction, reinforced concrete (RC) with masonry infill predominates, though traditional masonry's brittle nature poses significant seismic vulnerabilities. This study introduces a novel approach using Ductile Lightweight Fiber-Reinforced Concrete (DLFC) as an infill to address these challenges. Composed of cement, water, expanded polystyrene (EPS), ultra-fine filler, and combined polyvinyl alcohol (PVA) and polypropylene (PPF) fibers, DLFC aims to enhance ductility, minimize damage, and amplify energy absorption in seismic events. Three RC frames, with height-to-span ratios of 0.77, 1.00, and 1.28, were designed and experimentally tested under simultaneous vertical and lateral cyclic loading to evaluate DLFC's seismic response. Results illustrated that DLFC-infilled RC frames boast impressive ductility, an 8% drift at complete failure, minimal out-of-plane behavior, and elevated damping ratios. Remarkably, DLFC's low in-plane stiffness led to reduced frame stiffness compared to traditional masonry. An empirical equation, closely aligning with experimental outcomes, was formulated to estimate the lateral strength of the infill wall, and a comparison with the bare frame was made, though it necessitates additional validation through further testing.

Material Performance Evaluation of Cinder Based Light Weight Concrete with Micro-reinforcement

Objectives: The present work examines the viability of using industrial solid waste, like cinder, to create lightweight aggregate concrete. Utilizing cinder aggregate as a substitute material for coarse aggregate in producing concrete not only helps in the conservation of natural resource but also provides a feasible solution for solid waste management. Method: The mechanical characteristics of cinder based lightweight concrete were improved by the inclusion of polypropylene fibre as micro-reinforcement, in volume proportions of 0.1%, 0.2%, 0.3%, and 0.4%. The laboratory tests that were conducted on the polypropylene fibre reinforced cinder based lightweight concrete included compressive strength test on cube specimen and cylinder specimen, flexural strength test on prism specimen and modulus of elasticity test on cylinder specimen. Findings: The findings show that cinder aggregate can be satisfactorily utilized as an alternate material to coarse aggregate in the production of lightweight concrete. It has been found that 0.3% of polypropylene fibre was the ideal dosage of micro-reinforcement that can be incorporated in lightweight concrete. Novelty: Further, a multiple linear regression (MLR) model was suggested to evaluate the performance parameters of the fibre-reinforced lightweight concrete, providing an alternative to the time and material consuming experimental works. Scatter plots and Statistical indicators such as R2, RMSE and MAPE indicated that the model demonstrated a strong correlation between the predicted values and the experimental results. Keywords: Cinder aggregate, Lightweight concrete, Mechanical characteristics, Micro reinforcement, Regression model

Experimental study of lightweight concrete prepared from super absorbent polymers (SAPs) and glass fibers (GF)

ABSTRACT This study investigates the effect of super absorbent polymers (SAPs) and glass fiber (GF) additions on the properties of lightweight concrete. The SAPs act as a pore-forming agent, with the addition of various GF contents (0.1–1.0% by weight of dry ingredients). The results indicate that the use of SAPs at 7% by weight of OPC produces a product with similar properties to conventional lightweight concretes which meet the ASTM C332–17 standard. The addition of GF to the mixture tends to reduce the dry density and compressive strength, but increases the porosity and flexural strength. The results indicate that the use of SAPs at 7% by weight of OPC produces a product with similar properties to conventional lightweight concretes which meet the ASTM C332–17 standard. The 28-day compressive strengths decreased from 7.04 ± 0.07 for control sample to 4.59 ± 0.11 MPa, while the flexural strengths increased from 3.89 ± 0.04 for control sample to 6.72 ± 0.06 MPa. High-porosity lightweight concrete prepared from SAPs and GF shows reduced thermal conductivity and an increased sorption rate. The initial rate of water absorption gradually increases from 2.48 × 10−1 mm/sec0.5 in the sample without GF up to 5.45 × 10−1 mm/sec0.5 in the sample containing 1.0 wt.% GF. Comparison with the literature indicates that the use of SAPs as pore-forming agents in conjunction with GF has the potential to produce fiber-reinforced lightweight concrete with improved properties.

Flexural performance of steel-concrete-steel sandwich beams with lightweight fiber-reinforced concrete and corrugated-strip connectors: Experimental tests and numerical modeling

The present paper experimentally investigates the flexural behavior of steel-concrete-steel (SCS) composite beams with lightweight polypropylene fiber-reinforced concrete core and corrugated-strip shear connectors. For this purpose, the four-point bending tests have been performed on 11 specimens. This aims to investigate the influence of lightweight concrete core on the performance of the beams, and therefore all the parameters in the tested beams are kept constant except the type of concrete core. Based on the results of the performed quasi-static loading tests, the observed failure modes and force-displacement curves are reported and analyzed to achieve a deeper understanding of the influence of lightweight fiber-reinforced concrete on the flexural behavior of SCS beams. It was found that the utilization of polypropylene fiber has an improving influence on the performance of SCS beams, and especially enhances their toughness and ultimate deflection. A positive linear relationship between the fiber content (up to 2 %) with the specimen’s toughness was detected. It was also found that the addition of micro-silica to the lightweight fiber-reinforced concrete core results in considerable improvement in the flexural load capacity of the tested SCS beams. In addition, numerical finite element models including detailed material and geometric modeling of SCS beams are developed using the general software package ABAQUS. The accuracy of the developed models is validated using the attained experimental results. The numerical models can be used to simulate the load-deflection behavior and ultimate strength of SCS sandwich beams.

Compressive Cyclic Response of Steel Fiber-Reinforced Lightweight Concrete

Compressive Cyclic Response of Steel Fiber-Reinforced Lightweight Concrete

Experimental Study on Seismic Behavior of Lightweight Concrete-Filled Cold-Formed Steel Shear Walls Strengthened Using Horizontal Reinforcement

ABSTRACT To improve the seismic behavior and thermal property of traditional cold-formed steel (CFS) walls for satisfying the requirements multistory structures, a new type of fiber-reinforced lightweight concrete (FLC)-filled CFS shear wall strengthened using horizontal reinforcement is proposed in this study. Four full-scale specimens were tested under reversed cyclic loading to investigate the seismic behavior, including failure mode, hysteresis curve, shear capacity, deformability, stiffness degradation, and energy-dissipating capacity. Test results indicated that the restrictive effect of FLC on the studs and its diagonal-bracing effect improved the wall’s hysteretic behavior, making the wall exhibit the ductile shear failure. Increasing the wall thickness increased the shear strength, lateral stiffness, and energy-dissipating capacity, whereas installing the coupling-section interior studs enhanced the ductility. Finally, a simplified strut-and-tie model was proposed to evaluate the shear capability of FLC-filled walls, and the calculated values exhibited good agreement with the test results, but the further verification is required.

Optimization of a structural lightweight fiber-reinforced concrete for best performance under impact loading

Compared to normal concrete, lightweight fiber-reinforced concrete (LFRC) offers several advantages, such as a high tensile strength-to-weight ratio and high energy dissipation under impact loading. However, LFRC has a lower compressive strength and modulus of elasticity than normal concrete; finding the appropriate mix design is also essential for structural engineering. This study aims to determine the best mix proportion of LFRC by evaluating the mechanical characteristics and energy dissipation capacity under impact loading. For this purpose, an experimental study is performed to optimize the mix proportion using three types of lightweight aggregates (Leca, expanded perlite, and expanded polystyrene). Moreover, the effects of two different steel and polyvinyl alcohol fibers on LFRC properties are investigated to improve the fracture energy and tensile strength. In both phases, two Drop Weight impact and Modified Charpy impact tests are utilized in addition to the quasi-static tests (compressive, splitting tensile, and flexural tests). A quality function is proposed to achieve the best mix proportion of lightweight concrete. The results demonstrate that the mixture containing 50% expanded perlite replacement with normal weight aggregates, 20% Slag as partial replacement of cement, 0.25% PVA fiber, and 0.25% steel fiber has the best performance in the mechanical properties and energy dissipation capacity as a structural lightweight fiber reinforced concrete.

A new acoustically insulating fiber-reinforced lightweight concrete based on local materials and date palm waste

PurposeThis paper aims to characterize and develop a new ecological lightweight concrete reinforced by addition of palm plant fibers (from vegetal waste) to be used in the thermal and acoustical insulation of local constructions. The date palm plant fibers are characterized by their low sensitivity to chemical reactions, low cost and large availability in local regions. Therefore, the newly obtained lightweight concrete may suggest a great interest, as it seems to be able to achieve good solutions for local construction problems, technically, economically and ecologically.Design/methodology/approachThe experimental program focused on developing the composition of palm-fiber-reinforced concrete, by studying the effect of the length of the fibers (10, 20, 30 and 40 mm) and their mass percentage (0.5%, 1%, 1.5% and 2%), on the mechanical and acoustical properties of the composite. The main measured parameters were the compressive strength and flexural strength, sound absorption coefficient, noise reduction coefficient (NRC), etc. These tests were also borne out by the measure of density and water absorption, as well as microstructure analyses. To fully appreciate the behavior of the material, visualizations under optical microscope and scanning electron microscope analyses were carried out.FindingsThe addition of plant fibers to concrete made it possible to formulate a new lightweight concrete having interesting properties. The addition of date palm fibers significantly decreased the density of the concrete and consequently reduced its mechanical strength, particularly in compression. Acceptable compressive strength values were possible, according to the fibers content, while better values have been obtained in flexion. On the other hand, good acoustical performances were obtained: a considerable increase in the sound absorption coefficient and the NRC was recorded, according to the content and length of fibers. Even the rheological behavior has been improved with the addition of fibers, but with short fibers only.Originality/valueOver the recent decades, many studies have attempted to search for more sustainable and environmentally friendly building materials. Therefore, this work aims to study the possibility of using waste from date palm trees as fibers in concrete instead of the conventionally used fibers. Although many researches have already been conducted on the effect of palm plant fibers on the mechanical/physical properties of concrete, no information is available neither on the formulation of this type of concrete nor on its acoustical properties. Indeed, due to the scarcity of raw materials and the excessive consumption of energy, the trend of plant fibers as resources, which are natural and renewable, is very attractive. It is therefore a major recycling project of waste and recovery of local materials.

Application of Biomineralization Technology to Self-Healing of Fiber-Reinforced Lightweight Concrete after Exposure to High Temperatures.

In the field of civil engineering, concrete self-healing technology plays an important role. Concrete self-healing should be able to effectively heal cracks, not only improving the internal structure, but also improving the mechanical properties and durability of the concrete structure. The biomineralization-repair method is characterized by its potential for long-lasting, rapid, and active crack repair potential. Biomineralization repair has an effective bond ability, is compatible with concrete components, and is also environmentally friendly. This study used biomineralization to explore the self-healing of fiber-reinforced lightweight concrete after its exposure to high temperatures. Concrete specimens of a control group (using lightweight aggregate without bacterial spores and a nutrient source) and an experimental group (using lightweight aggregate containing bacterial spores and a nutrient source) were prepared. The repair effect of the microbial self-healing concrete after the exposure to high temperature was observed by a crack-width gauge, field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). According to the EDS and XRD analyses, the precipitate formed at the crack was calcium carbonate. After 28 days of self-healing, the water absorption rate of the experimental group was lower than that of the control group. This is because the specimens of the penetration test were taken from the middle of the concrete cylinder after high temperature, and their bacterial survival rate was higher, which made the mineralization more significant. However, the mechanical test results of the control and experimental groups after the self-healing in the water were not substantially different, which indicated that the bacterial mineralization in the experimental group was slow in the absence of an adequate source of nutrients.

Prediction of Mechanical Properties of Highly Functional Lightweight Fiber-Reinforced Concrete Based on Deep Neural Network and Ensemble Regression Trees Methods.

Currently, one of the topical areas of application of artificial intelligence methods in industrial production is neural networks, which allow for predicting the performance properties of products and structures that depend on the characteristics of the initial components and process parameters. The purpose of the study was to develop and train a neural network and an ensemble model to predict the mechanical properties of lightweight fiber-reinforced concrete using the accumulated empirical database and data from construction industry enterprises, and to improve production processes in the construction industry. The study applied deep learning and an ensemble of regression trees. The empirical base is the result of testing a series of experimental compositions of fiber-reinforced concrete. The predicted properties are cubic compressive strength, prismatic compressive strength, flexural tensile strength, and axial tensile strength. The quantitative picture of the accuracy of the applied methods for strength characteristics varies for the deep neural network method from 0.15 to 0.73 (MAE), from 0.17 to 0.89 (RMSE), and from 0.98% to 6.62% (MAPE), and for the ensemble of regression trees, from 0.11 to 0.62 (MAE), from 0.15 to 0.80 (RMSE), and from 1.30% to 3.4% (MAPE). Both methods have shown high efficiency in relation to such a hard-to-predict material as concrete, which is so heterogeneous in structure and depends on many factors. The value of the developed models lies in the possibility of obtaining additional useful information in the process of preparing highly functional lightweight fiber-reinforced concrete without additional experiments.

Influence of the Chemical Activation of Aggregates on the Properties of Lightweight Vibro-Centrifuged Fiber-Reinforced Concrete

One of the most essential building materials for sustainable development is concrete. However, there is a problem with a lack of inexpensive, efficient ways to make it high-strength and ultra-dense. A promising direction is the additional processing or activation of the cheapest component of the concrete mixture—inert aggregate. The article is devoted to a promising method for the simultaneous activation of both large and small aggregates using vibro-centrifuge technology. It has been established that the activation of concrete aggregates with aqueous solutions of natural bischofite at a concentration of 6 g of dry matter per 1 L of water is the most rational and contributes the maximum increase in strength characteristics and the best values of strain characteristics. Strength characteristics increased up to 16% and ultimate strains increased to 31%, respectively, and the modulus of elasticity increased to 9%. A new improved lightweight fiber-reinforced concrete was created and an innovative technology is proposed that makes it possible to achieve savings in manufacturing due to a significant improvement in structural properties and reducing the working sections of reinforced concrete elements. Regularities between the fundamental chemical processes of the surface activation of aggregates and the physical processes of structure formation of compacted and hardened concrete were revealed. An improvement in the structure of concrete at the micro- and macro-levels was recorded due to a point decrease in crack formation at the interfaces of the “cement matrix-aggregate” and “cement matrix-fiber” phases, and a decrease in the number of micropore defects was also found. Economic efficiency reached 25–27%.

The Properties of Glass Fiber Reinforced Lightweight Concrete under the Effect of High Temperature

This study aimed to produce lightweight concrete by using 50% pumice as coarse aggregate and 0.1% and 0.3% glass fiber. It is aimed to investigate the changes that will occur in the compressive strength and splitting tensile strength properties of the samples when this lightweight concrete produced is exposed to temperatures of 150 °C, 300 °C, 450 °C and 600 °C. The study was carried out in six stages. In the first stage, reference samples were produced. In the second stage, 0.1% and 0.3% glass fiber reinforced lightweight concrete samples were produced. In the third stage, unit weight, porosity, compressive strength and splitting tensile strength tests were applied to the produced samples. In the fourth step, the samples were gradually exposed to different temperatures (150 °C, 300 °C, 450 °C and 600 °C). In the fifth stage, compressive strength and splitting tensile strength tests were applied to the samples exposed to high temperature. In the sixth and final stage, SEM images of 0.1% glass fiber reinforced lightweight concrete samples were analysed. As a result, it was observed that the unit weight value decreased and the porosity values increased with glass fiber reinforcement. There was also an increase in compressive and splitting tensile strengths. In addition, it was observed that the samples exposed to 150 oC temperature had the highest compressive strength and splitting tensile strength. In the analysis of SEM images, with the increase in temperature, it was determined that the samples in microstructure changed into macrostructure as well as the cracks occurred in the sample structure. The importance of this study stem from increasing tensile strength of lightweight concrete with glass fiber reinforcement so as to prevent loss of life and property in an earthquake.This study is important because it increases the tensile strength of lightweight concrete with low tensile strength with glass fiber reinforcement. This will result in less loss of life and property in an earthquake. Keywords: Glass fiber, pumice, lightweight concrete, high temperature DOI: 10.7176/CER/14-4-07 Publication date: June 30 th 2022

ВЛИЯНИЕ ВИДА ПРИМЕНЯЕМЫХ ФИБРОВЫХ ВОЛОКОН НА ПРОЧНОСТЬ И ДЕФОРМАТИВНОСТЬ ДИСПЕРСНО-АРМИРОВАННЫХ ОБЛЕГЧЁННЫХ БЕТОНОВ

Fiber-reinforced concretes with improved strength and deformation characteristics are widely used in construction. The research is aimed to study the stress-strain condition of lightweight fiber-reinforced concrete, to plot stress-strain diagrams and analyze them. In total, four series of prism specimens are manufactured and tested. The first series is the control composition of lightweight concrete; the second series is lightweight concrete with a basalt fiber content of 3%; the third series is lightweight concrete with a glass fiber content of 3 %; the fourth series is lightweight concrete with a basalt fiber content of 1.5 % and 1.5 % glass fiber. The experimental studies demonstrate that lightweight concrete reinforced with basalt fiber has the highest deformability. In comparison with glass fiber, basalt fiber has a higher tensile strength and a higher elastic modulus. The fact that the concrete matrix and basalt fiber work together better is primarily due to the best mechanical characteristics of the basalt fiber. Further research prospects are determined in terms of determining the adhesion strength of various types of fibers with a matrix and studying the effect of this indicator on both the strength and deformation characteristics of lightweight concrete.

Constitutive Model for Plain and Fibre-Reinforced Lightweight Concrete Under Compression

Constitutive Model for Plain and Fibre-Reinforced Lightweight Concrete Under Compression

Improvement of Strength and Strain Characteristics of Lightweight Fiber Concrete by Electromagnetic Activation in a Vortex Layer Apparatus

The relevant problem of choosing effective materials for enclosing structures is compliance with the requirements of increased thermal resistance, reduced mass of buildings and structures, and reduced material consumption, labor intensity, and construction costs. These requirements are satisfied by structures made of lightweight fiber-reinforced concrete, which are the subject of attention of many scientists and engineers. One of the most rational requirements for industrial use is the activation of untreated components of the concrete mixture. This article is devoted to studying the influence of the activation of fiber-reinforced concrete elements in the vortex layer apparatus on concrete strength and structural characteristics. The effect of the raw component processing time of the concrete mixture on the strength and deformation characteristics of the lightweight fiber-reinforced concrete was studied. The optimal processing time for the cement–sand mortar in the VLA-75-85s was determined. It was shown that the activation of the vortex layer in the apparatus leads to an increase in strength from 27% to 61% and an improvement in the deformation characteristics of lightweight fiber-reinforced concrete by up to 12%. Furthermore, it was found that the use of activation in VLA leads to an increase in the coefficient of constructive quality for all experimentally determined strength characteristics of lightweight fiber-reinforced concrete by up to 27%.

Nanomodification of Lightweight Fiber Reinforced Concrete with Micro Silica and Its Influence on the Constructive Quality Coefficient.

A hypothesis was put forward that a nano-modifying additive of micro silica, which had a beneficial effect on achieving a perfect structure of heavy concrete, can also be effectively used in lightweight fiber-reinforced concrete. The nano-modifying additives of micro silica application in manufacturing lightweight fiber reinforced concrete products and structures can significantly enchain their strength characteristics without increasing their mass and consequently improve their design characteristics. The purpose of the work was to increase the structural quality coefficients for all types of strengths of lightweight fiber-reinforced concrete due to its modification with micro silica. The effect of nano-modifying additives of micro silica on the strength characteristics of lightweight fiber reinforced concrete was studied. The optimal amount of micro silica addition was experimentally confirmed and established of 10% of the cement mass. The coefficients of constructive quality for all experimentally determined strength characteristics of lightweight fiber-reinforced concrete modified with micro silica additives were calculated. The coefficient of constructive quality for tensile strength in bending of lightweight fiber reinforced concrete with additives was two and a half times higher than that of heavy concrete without additives and up to 37% higher than that of lightweight fiber-reinforced concrete without additives.

Mechanical Properties of Barchip Polypropylene Fibre-reinforced Lightweight Concrete Made With Recycled Crushed Lightweight Expanded Clay Aggregate

Concrete is one of the broadly used construction materials in the construction industry. This research intends to recommend the replacement of conventional coarse aggregates with recycled lightweight expanded clay aggregate (LECA) which offers several advantages such as lightweight, low cost, and easy availability. Lightweight concrete (LWC) offers numerous benefits; therefore, many researchers are using lightweight aggregate to produce lightweight structural composites concrete to compensate heavy loads by reducing the concrete self-weight due to lower density of lightweight concrete, improving in thermal properties and fire resistance, saving the cost of transportation and handling of precast units in the site. Different percentages (0, 0.15, 0.30, and 0.45%) of volume fraction of barchip polypropylene (BPP) fibre have been incorporated to improve the mechanical properties of lightweight aggregate concrete (LWA) concrete. In this study, the mixture of crushed lightweight expanded clay aggregate (CLECA) and barchip polypropylene (BPP) fibre have been used to achieve compressive strength between 28 and 37 MPa at 28-days with an oven-dry density ranged between 1900 and 2000 kg/m3. It is found that the inclusion of BPP fibres at an optimum volume fraction concrete enhances the compressive strength, splitting tensile strength and modulus of rupture. The compressive strength of the lightweight aggregate concrete containing 0.45% volume fraction of BPP fibre (CLLWAC-BPP0.45%) had achieved the highest compressive strength of 37 MPa at 28-days with a significant increment of about 31% compared to plain concrete. Hence, the findings of this research showed that the development of eco-friendly lightweight structural composites can be used as an alternative solution for conventional lightweight concrete, infrastructure and marine fields application.

Fiber-reinforced lightweight concrete formulated using multiple residues

Waste from mineral extraction and the manufacturing industry can be used to produce lightweight concrete. Moreover, fiber-reinforcing lightweight concrete is capable of reducing structural weight and piece sections, resulting in a variety of applications such as flooring, shotcrete and precast concrete. This work aimed at studying fiber-reinforced lightweight concrete mixtures prepared with the combined addition of multiple residues, i.e., rubber, limestone and porcelain dust residues along with expanded clay. 0.2% to 0.6 vol% steel, polypropylene, glass and carbon fibers, were studied. A reference fiber-free lightweight mixture with compressive strength of 32 MPa was also produced. The physical characteristics of the mixtures were evaluated by consistency tests, void indices, water absorption and density measurements. The mechanical characterization was carried out by compressive, flexural and fracture strength in addition to toughness tests. The results indicated that the addition of fibers decreased the workability of the concrete, but improved flexural and fracture strength along with toughness. The effects of fiber volume and properties, such as shape factor, tensile stress and elastic modulus on the properties of the resulting materials were evaluated. Steel and carbon fibers resulted in the best fracture strength properties, due to their high modulus of elasticity and tensile strength.