Expanded Polystyrene Lightweight Research Articles

Enhancing Sustainability in Construction: Investigating the Thermal Advantages of Fly Ash-Coated Expanded Polystyrene Lightweight Concrete

This study investigates a sustainable coating method for modified expanded polystyrene (MEPS) beads to improve the thermal insulation of lightweight concrete intended for wall application. The method employed in this study is based on a novel coating technique that represents a significant advancement in modifying Expanded Polystyrene (EPS) beads for enhanced lightweight concrete. This study experimentally assessed the energy-saving capabilities of MEPS concrete in comparison to control groups of uncoated EPS beads and normal concrete by analysing early-stage temperature, thermal conductivity, specific heat capacity, heat flux, and thermal diffusivity. The thermal conductivity of MEPS concrete is approximately 40% lower than that of normal concrete, demonstrating its usefulness in enhancing insulation. The heat flux calculated for MEPS concrete is significantly reduced (approximately 35%), and it has a 20% lower specific heat capacity than ordinary concrete, indicating a reduction in energy transfer through the material and, thus, potential energy-efficiency benefits. Furthermore, the study discovered that all test objects have very low thermal diffusivity values (less than 0.5 × 10−6 m2/s), indicating a slower heat transport through the material. The sustainable coating method utilized fly ash-enhanced thermal efficiency and employed recycled materials, hence decreasing the environmental impact. MEPS concrete provides a practical option for creating sustainable and comfortable buildings through the promotion of energy-efficient wall construction. Concrete incorporating coated EPS can be a viable option for constructing walls where there is a need to balance structural integrity and adequate insulation.

Experimental Investigation of Mechanical Properties of Concrete Mix with Lightweight Expanded Polystyrene and Steel Fibers

The demand for lightweight aggregates in concrete compositions for diverse structural and non-structural applications in contemporary building construction has increased. This is to achieve a controllable low-density lightweight concrete, which reduces the overall structural weight. However, the challenge lies in achieving an appropriate strength in lightweight concrete while maintaining a lower unit weight. This research aims to evaluate the performance of lightweight concrete by integrating expanded polystyrene (EPS) as a partial replacement for coarse aggregate. Test specimens were cast by blending EPS with coarse aggregate at varying proportions of 0%, 15%, 30%, and 45%, while maintaining a constant water-to-binder ratio of 0.60. To enhance the bonding and structural capabilities of the proposed lightweight concrete mixes, reinforcement with 2% and 4% steel fibers by volume of the total concrete mix was incorporated. Silica fume was introduced into the mix to counteract the water hydrophobicity of EPS material and enhance the durability of lightweight concrete, added at a rate of 10% by weight of cement in all specimens. A total of 60 samples, including cylinders and beams, were prepared and cured over 28 days. The physical and mechanical properties of the lightweight EPS-based concrete were systematically examined through experimental testing and compared against a standard concrete mix. The analysis of the results indicates that EPS-based concrete exhibits a controllable low density. It also reveals that incorporating reinforcement materials, such as steel fibers, enhances the overall strength of lightweight concrete.

Experimental Study on Flexural Behavior of RC–UHPC Slabs with EPS Lightweight Concrete Core

This paper presents an experimental investigation that focuses on the flexural behavior of an innovative reinforced concrete–ultra-high performance concrete slab with an expanded polystyrene lightweight concrete core. This type of slab is proposed to serve the semi-precast solution, in which the bottom layer is ultra-high performance concrete working as a formwork during the construction of semi-precast slab, the expanded polystyrene lightweight concrete layer is used for the reduction of structure self-weight, and the top layer is normal concrete designed to withstand compressive stress when the slab is loaded. Two similar large-scale specimens with dimensions of 6200 mm × 1000 mm × 210 mm were fabricated and tested under four-point bending conditions to investigate the flexural behavior of composite slab. Test results indicated that three different layers of materials can work effectively together without separation. The bottom ultra-high performance concrete layer leads to the high ductility of the slab and has a good effect in limiting the widening of the crack width by forming other cracks. According to design code ACI 544.4R, a modified distribution stress diagram on the composite section was proposed and proven to be suitable for the prediction of flexural strength of the composite section with an error of 3.4% compared to the experimental result. The effect of the ultra-high performance concrete layer on the flexural strength of the composite slab was clearly demonstrated, and for the case in this study, the ultra-high performance concrete layer improves the flexural strength of the slab by about 11.5%.

Study on Dynamic Modulus and Damping Characteristics of Modified Expanded Polystyrene Lightweight Soil under Cyclic Load.

In recent years, expanded polystyrene (EPS) lightweight soil has been widely used as subgrade in soft soil areas because of its light weight and environmental protection. This study aimed to investigate the dynamic characteristics of sodium silicate modified lime and fly ash treated EPS lightweight soil (SLS) under cyclic loading. The effects of EPS particles on the dynamic elastic modulus (Ed) and damping ratio (λ) of SLS were determined through dynamic triaxial tests at various confining pressures (σ3), amplitudes, and cycle times. Mathematical models of the Ed of the SLS, cycle times, and σ3 were established. The results revealed that the EPS particle content played a decisive role in the Ed and λ of the SLS. The Ed of the SLS decreased with an increase in the EPS particle content (EC). The Ed decreased by 60% in the 1-1.5% range of the EC. The existing forms of lime fly ash soil and EPS particles in the SLS changed from parallel to series. With an increase in σ3 and amplitude, the Ed of the SLS gradually decreased, the λ generally decreased, and the λ variation range was within 0.5%. With an increase in the number of cycles, the Ed of the SLS decreased. The Ed value and the number of cycles satisfied the power function relationship. Additionally, it can be found from the test results that 0.5% to 1% was the best EPS content for SLS in this work. In addition, the dynamic elastic modulus prediction model established in this study can better describe the varying trend of the dynamic elastic modulus of SLS under different σ3 values and load cycles, thereby providing a theoretical reference for the application of SLS in practical road engineering.

Homogenization approach for estimating the effective thermal conductivity of Lightweight Expanded Polystyrol Concrete

This paper aims to determine the macroscopic thermal conductivity coefficient of Lightweight Expanded Polystyrene Concrete (LEPS-C) using the homogenization approach through analytical calculations. The influence of expanded polystyrene on the overall thermal conductivity coefficient of LEPS-C was determined using classical homogenization models based on the solution of the Eshelby problem, with the matrix phase being concrete and the inclusion phase being expanded polystyrene particles randomly distributed in the matrix phase. The content of substituted expanded polystyrene particles was varied from 0% to 40% by volume of concrete. The analytical calculation results obtained from the homogenization models were compared with the experimental results, showing good agreement and demonstrating the efficacy of the homogenization method in predicting the macroscopic thermal conductivity of LEPS-C.

Effects of Freeze-Thaw Cycles on the Mechanical Properties of Lightweight Expanded Polystyrene (Eps) Soils

Effects of Freeze-Thaw Cycles on the Mechanical Properties of Lightweight Expanded Polystyrene (Eps) Soils

Cyclic performance tests and numerical analysis of prefabricated CFS shear walls filled with lightweight EPS mortars

With the advancement and promotion of green buildings, infilled cold-formed steel (CFS) shear walls have gained considerable attention. In order to promote the assembly degree, novel prefabricated CFS shear walls filled with lightweight expanded polystyrene (EPS) mortars is developed and their corresponding connection method are also developed in this paper. Then, integral prefabricated lightweight EPS mortars (LEM)-filled CFS shear wall and four spliced shear walls assembled using three separated shear walls were designed and tested to evaluate their cyclic performance. The failure patterns, load–displacement relationships, feature values, ductility, stiffness and energy dissipation were systematically analyzed and asserted. The results indicated that prefabricated LEM-filled shear wall appeared superior cyclic performance and spliced shear wall could be used in engineering practice to improve the standardization produce. Subsequently, three-dimensional finite element (FE) models of prefabricated LEM-filled CFS shear walls were established and verified by the experimental data. The FE models considered the initial imperfection of wall studs, nonlinear behavior of the self-drilling screws, and the assembling of separated shear walls. Moreover, the contact stress distributions between the CFS components and LEMs were also analyzed. Finally, a simplified model considering the assembly feature was proposed to predict the shear bearing capacity of the prefabricated shear wall. The exploration illustrated that enhancing the connections between the separated shear walls is an effective measure to guarantee the wall strength. The test and analytical results provide guidance for the application of prefabricated LEM-filled CFS shear walls and promote their development.

Performance of expanded polystyrene light weight self compacting concrete in composite slab

ABSTRACT Composite constructions have gained importance due to faster and economical construction. Composite sections are generally made with cold formed corrugated profile sheet, which also act as a permanent formwork. To promote the use of composite sections in construction industry, it is necessitate to target to minimize the self-weight. It also facilitates to save the construction cost. In composite slabs, shear connectors are provided for composite action. It would be difficult to pour the conventional concrete; hence self compacting concrete would be ideally suited for such places. To reach the above objective, an effort has been made to investigate the expanded polystyrene light weight self compacting concrete in composite slab. To achieve the light weight concrete, expanded polystyrene beads were added in different proportions to the coarse aggregate. The composite slab was performed for four-point bending test under flexure and push out test. The test result concluded that the light weight expanded polystyrene self compacting concrete composite slab exhibit a higher performance with reduction in the thickness of the slab. The minimum spacing of shear connector was well performed. It could able to control the shear crack and de-bonding effect between the profiled steel sheet and concrete.

Design and construction of lightweight EPS geofoam embedded geomaterial embankment system for control of settlements

This paper presents a research study on a bridge site located along US highway 67 over SH 174 in Cleburne, Texas, where bridge approach slabs have experienced more than 0.4 m (17 in.) of settlement within a span of 16 years after construction. Many treatment methods attempted to mitigate this problem had proven to be ineffective. As part of novel rehabilitation works, the top of existing fill soil on the embankment was replaced with lightweight expanded polystyrene (EPS) geofoam blocks to alleviate the approach slab settlements. This paper describes initial design and construction details of the rehabilitation works performed on the embankment system along with a focus on the early performance details. Field monitoring studies were conducted for almost three years to study the bump/settlements under the EPS geofoam embankment system. Short term measured settlement data was analyzed with hyperbolic model to predict the long term settlements. Numerical finite element studies attempted in this study showed that settlements could be reasonably predicted by modeling these geofoam embankments. Based on the monitoring and modeling studies, the effectiveness of utilizing EPS geofoam as an embankment fill material was addressed to mitigate the differential settlements under a bridge approach slab.

Testing and modeling the behavior of sandwich lightweight panels against wind and seismic loads

The behavior of non-structural sandwich lightweight panels against wind and seismic loadings is not well understood. Such panels are typically composed of two calcium-silicate board (CSB) wythes separated by a core infill made of expanded polystyrene lightweight concrete (LWC). This paper provides understanding regarding the mechanisms of panel connectivity by tongue-and-groove, including transfer of forces through steel dowels to the existing structure. Series of LWC mixtures having 470 to 975 kg/m3 density were tested using suitably established testing procedures to determine the flexural strength, core shear strength, interfacial bond between LWC and CSB, and pullout forces transmitted through the steel dowels. Special emphasis is placed on modeling the effect of wind and seismic loads on a 3.6 × 3 m2 partition wall constructed using LWC sandwich panels. The highest stresses and deformations generated from the model are compared to those determined experimentally, which allowed establishing different charts that can predict the safety factors as a function of LWC density and type/magnitude of the lateral loading applied.

Effects of viscosity modifying admixture (VMA) on workability and compressive strength of structural EPS concrete

The lightweight expanded polystyrene (EPS) concrete has the characteristics of vibration energy absorption and can be used to conduct the metro track of vibration reduction and isolation. But the workability and compressive strength of the lightweight EPS concrete need to be improved in the engineering application of vibration energy absorption when EPS beads are mixed in concrete. To improve the workability and compressive strength, this paper investigated the effects of viscosity modifying admixture (VMA) on the workability, segregation resistance, compressive strength and failure mode of a class of structural lightweight EPS concrete, prepared by controlling a certain water-binder ratio and fly ash replacement. The dosage of VMA in the mixtures was 0.02%, 0.04%, 0.06%, 0.08% and 0.10% by weight of the total cementitious materials (TCM), respectively. Workability was investigated through a multi-index of slump, slump flow, T50 and inverted slump cone time while segregation resistance was evaluated by a density test. The concept of anisotropy was employed to evaluate the compressive strength and failure mode. Results showed that VMA had significant negative effects on the fluidity of structural EPS concrete. From the density test results, VMA significantly enhanced the resistance to segregation and the segregation degree of EPS concrete exhibited a negative linear correlation with the dosage of VMA according to the definition of segregation index (SI). The compressive strength decreased substantially with increase of VMA and the anisotropy of the strength was shown to be inhibited gradually with increase of VMA, resulting from the improvement of resistance to segregation. As the elimination of anisotropy, the failure modes were altered consequently. In terms of the effectiveness to inhibit the segregation and the anisotropy, 0.10% by weight of TCM was recommended as the most effective dosage for VMA in this paper.

Effect of matrix particle size on EPS lightweight concrete properties

Expanded polystyrene lightweight concrete is a composite which can be made by adding expanded polystyrene aggregate in normalweight concrete (as matrix). The research was focused on the effect of properties and volume of the matrix on the properties of lightweight concrete. The results show that properties of structural polystyrene concrete, such as workability and compressive strength, depend on the aggregate size of the matrix. It also shows that decreasing aggregate size of the matrix is the effective way to increase workability and compressive strength of lightweight concrete. When the density of concretes decrease by 200 kg/m³, slump values decrease by about 20 to 30 mm with lightweight concrete mixtures using maximum particle size of 0.63 mm, while slump values decrease by about 40 mm with the mixtures using maximum particle size of 20 mm. At the same density, the compressive strength of the structural polystyrenre concrete significantly decreased when the coarse aggregate diameter greater than 10 mm. Therefore, coarse aggregates with diameter size are smaller than 10 mm was recommended to use for matrix. In the result, expanded polystyrene concrete with density from 1,400 kg/m³ to 2,000 kg/m³ and compressive strength more than 20 MPa for structural application was made.

Optimization of Expanded Polystyrene Lightweight Aggregate in Pre-Cast Concrete Blocks by a Completely Random Experimental Design (CRED) with Mixture and Process Variables

The aim of this study was to determine the optimum design mix to produce pre-cast concrete blocks by a completely random experimental design (CRED) with mixture and process variables. The polymerized concrete was studied its composition: Cement, and water defined as the mixture compounds. To choose the best model, all the possible models were assessed through the ANOVA, which tested each possible model. The linear-linear model was preferred, since that do not present evidence of lack of fit, and it is capable of relating how to react the process variables, when are changed the variable mixture condition levels. The optimum experimental condition, obtained for the polymerized concrete, was: The size of the polystyrene beads was 4.8 mm sized polystyrene beads, 5.0% polystyrene that replaced the aggregate, 18.3% cement, 73.4% aggregate and 8.3% water. In this condition, the blocks made with polymerized concrete show a compressive strength above 15 Mpa, allowing its utilization in paving.

Prediction of compressive strength and elastic modulus of expanded polystyrene lightweight concrete

Expanded polystyrene (EPS) lightweight concrete is composed of a plain concrete matrix and EPS beads. The aim of the study was to characterise the mechanical properties of EPS lightweight concretes containing various volumes of EPS (0%, 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40%) and of two water/cement ratios (0·45 and 0·55). The test results indicate that the apparent density, compressive strength, splitting tensile strength and elastic modulus of EPS concrete decrease when the content of EPS particles increases. Based on the experimental results and composite approach, a new simplified mathematical model is proposed for evaluating the compressive strength and elastic modulus of EPS concrete as a function of the mechanical properties of the plain concrete, the mechanical properties of the EPS and the percentage of EPS particles.

Mechanical properties of expanded polystyrene lightweight aggregate concrete and brick

In this study, mix proportion parameters of expanded polystyrene (EPS) lightweight aggregate concrete are analyzed by using Taguchi’s approach. The density, compressive strength and stress–strain behavior were tested. The optimal mixture of EPS lightweight aggregate concrete was selected among experiments under consideration to manufacture the lightweight hollow bricks. The results show that EPS dosage has the most significant effect on compressive strength of EPS lightweight aggregate concrete, then water and cement ratio, while the content of cement and sand ratio play a comparatively less important part. The relationship between density and compressive strength of EPS lightweight aggregate concrete is proposed as f c = 2.43 × γ 2.997 × 10 −9. The legitimacy of the use of EPS lightweight bricks made by EPS lightweight aggregate concrete is confirmed.

Investigating Mix Proportions of Lightweight Expanded Polystyrene Concrete

An experimental program was carried out to obtain the density and compressive strength of lightweight expanded polystyrene (EPS) concretes. Tauchi’s approach was adopted to reduce the numbers of experiment. Four control factors and two responses were used. The results show that EPS dosage had the most significant effect on density and compressive strength. The density value of EPS concrete showed an almost linear decrease as the volume of EPS and W/C parameters increased, but results in a decrease in compressive strength.

OPTIMIZATION MIX PROPORTION OF EXPANDED POLYSTYRENE LIGHTWEIGHT CONCRETE FOR MANUFACTURE W ALL AND FLOOR PANELS OF BUILDING ASSEMBLED

The use of prefabricated lightweight concrete panels like wall, floor, roof can help cut down construction cost while maintains the quality of the building. This method has been used effectively in many developed countries and has proved to be appropriate in Vietnam condition. This paper deals with fabrication expanded polystyrene (EPS) lightweight concrete panels base on increasing strength of mortar matrix and optimization porous structure. In this research, we studied EPS lightweight concrete with density of 875 - 1150 kg/m3 and compression strength of 7.5 - 15 MPa for manufacturing wall panels. EPS lightweight concrete with density of 1275 kg/m3 and compression strength of 20 MPa for manufacturing floor and roof panels.

Experimental study of lightweight expanded polystyrene aggregate concrete containing silica fume and polypropylene fibers

We developed a new structural lightweight concrete by totally or partially replacing coarse and fine aggregates in high performance concrete by expanded polystyrene (EPS) beads. In this work, the sizes of EPS bead were 1.0, 2.5 and 6.3 mm. Lightweight EPS concretes with a wide range of concrete densities and compressive strengths were successfully developed. Compressive strength, splitting tensile strength, shrinkage, and water absorption were examined. Additionally, fine silica fume (SF) and polypropylene (PP) fibers were added to improve the mechanical and shrinkage properties of EPS concretes. The results show that fine SF greatly increases the bond strength between the EPS beads and cement paste, thus increasing the compressive strength of EPS concrete. With inclusion of PP fibers, drying shrinkage properties are significantly improved.

Effects of vibration technology and polyvinyl acetate emulsion on microstructure and properties of expanded polystyrene lightweight concrete

To prevent expanded polystyrene (EPS) beads from rising up to the surface in the molding process of EPS lightweight concrete, vibration with pressure was applied and the polyvinyl acetate (PVA) emulsion was adopted to improve its mechanical properties. The mechanical properties, thermal properties and durability of EPS lightweight concrete were tested. The microstructures of EPS lightweight concrete were observed by scanning electron microscope (SEM). Vibration with pressure reduces the number of small cracks. The 180 d compressive strength and flexural strength increase obviously as a large amount of PVA was added. The mixed amount of PVA has no obvious influence on the thermal performance when it is not more than 10% of the cement. Vibration with pressure and surface modification of EPS beads by PVA improve the combination of EPS beads with cement stone and the mechanical properties of EPS lightweight concrete.