Performance Of Lightweight Aggregate Concrete Research Articles

Enhancing Sustainability in Construction: An Evaluation of Lightweight Concrete with Sintered Fly Ash and Waste Marble Sand

Abstract Marble waste and fly ash are industrial waste, and disposal of these wastes is a big challenge for environmental sustainability. In this study, we explore an innovative approach to sustainable construction by utilizing industrial by-products: sintered fly ash aggregate (SFA) and waste marble sand in lightweight aggregate concrete (LWAC). This study used SFA as a coarse aggregate, whereas river sand was partially replaced by waste marble sand (10–50 %). The waste marble sand modified LWAC has been investigated for mechanical and durability properties. The test related to permeability like water absorption, sorptivity, permeability, and drying shrinkage has been performed. Mercury intrusion porosimetry test was performed to validate durability results. The results indicate that 30 % of river sand can be replaced with waste marble sand as it improves the overall performance of LWAC. Our research contributes to global sustainability efforts by providing a method to reduce industrial waste through its incorporation in building materials. This study not only addresses the urgent need for environmental preservation but also offers potential enhancements in the mechanical properties of LWAC, making it a viable and eco-friendly option in the construction industry worldwide.

Experimental study on strength and carbonation performance of hybrid fibre lightweight aggregate concrete in precast structures

To improve the brittle failure characteristics and carbonation performance of lightweight aggregate concrete, basalt fibre, and polyacrylonitrile fibre were incorporated. The effects of the two fibres on the compression strength and carbonation depth were studied through compression tests and rapid carbonation tests. The effects of mineral admixture proportion were also studied. The results show that when the mass content of basalt fibre and polyacrylonitrile fibre is 2.8 kg/m3 and 0.9 kg/m3, respectively, the average increase of compression strength for different ages is approximately 40%, and the average decrease of carbonation depth for different ages is approximately 8%. Furthermore, when the mass content of mineral admixture is 30%, the higher proportion of slag contributed to the greater compression strength, but smaller carbonation depth. As supported by the experimental results, the improvements in strength and carbonation performance of lightweight aggregate concrete will make it more competitive in the application of precast buildings and long-span bridges.

Toughness Performance of Lightweight Aggregate Concrete Reinforced with Steel Fibers

Toughness Performance of Lightweight Aggregate Concrete Reinforced with Steel Fibers

Structural Performance of Lightweight Aggregate Concrete Reinforced by Glass or Basalt Fiber Reinforced Polymer Bars.

Lightweight aggregate concrete (LWC) and fiber reinforced polymer (FRP) reinforcement are potentially more sustainable alternatives to traditional steel-reinforced concrete structures, offering several important benefits. To further the knowledge in this area, the physical–mechanical properties of LWC produced with 0%, 50%, and 100% expanded clay aggregate were assessed. Subsequently, the flexural behavior of LWC beams reinforced with steel reinforcement and glass and basalt FRP bars was tested. The results of the experimental program allowed quantifying of the effect of expanded clay aggregate incorporation on LWC properties. The use of FRP reinforcement was also compared to steel-reinforced concrete beam behavior. The results of this study can provide additional support for the use of innovative materials such as LWA and FRP reinforcement.

Effect of Coal Bottom Ash as Partial Sand Replacement for Lightweight Aggregate Concrete

Environmental degradation due to disposal of waste namely coal bottom ash waste from thermal power plant, clinker waste of palm oil mill and river sand mining activity for concrete production need to be resolved. Palm oil clinker lightweight concrete with zero granite aggregate that been produced in effort to reduce dependency of natural stone consumption has been further explored its potential in this research. Thus, the present research investigates the compressive strength, water absorption and acid resistance of lightweight aggregate concrete containing coal bottom ash as partial sand replacement. Five types of concrete mixes were produced using 0%, 10%, 20%, 30% and 40% coal bottom ash as fine aggregate replacement. After curing process, specimens were immersed in acid hydrochloric solution before subjected to compressive strength testing. Findings show that all specimen experience strength reduction after exposed to acidic environment. On overall, the use of coal bottom ash influences the durability performance of lightweight aggregate concrete.

Assessment of the Thermal Performance of Lightweight Aggregate Concrete Through Different Test Methods

Assessment of the Thermal Performance of Lightweight Aggregate Concrete Through Different Test Methods

Effect of concrete type on equivalent lateral confinement pressure in columns under axial loads

The objective of this study is to evaluate the effect of the concrete type, compressive strength of concrete (fc′), amount of transverse reinforcement (Ash), and tie-configuration on the stress–strain curve of confined concrete obtained from the axial performance of lightweight aggregate concrete (LWAC) columns. Sixteen LWAC columns were tested under a concentric axial load. The test results show that the slope of the descending branch in the axial strain against applied axial load decreases with an increase in Ash and decrease in fc′. This trend was more prominent in all-lightweight aggregate concrete (ALWAC) columns compared with sand-lightweight aggregate concrete (SLWAC) columns. For a similar Ash, the strength gain factor (Ks) and equivalent uniform lateral pressure (fle) of ALWAC columns were slightly lower than those of the SLWAC columns, which were considerably lower than those of normal-weight concrete (NWC) columns. In particular, the descending slope of the stress–strain curves of confined concrete was more brittle in ALWAC columns with conventional crossties, lower Ash, and higher fc′ compared to SLWAC with diamond-shaped ties. Consequently, there was a significance discrepancy between measured and predicted values of the stress–strain curves of confined concrete proposed by Saatcioglu and Razvi in the ALWAC column with an Ash value of 1.0, a fcd value of 40 MPa, and conventional crossties, resulting in the highest mean (γm) and standard deviation (γs) of the normalized root-mean-square error (NRMSE).

Comparative analysis of the effects of aggregates and fibres on the fracture performance of lightweight aggregate concrete based on types I and II fracture test methods

This study aims to evaluate different influencing factors, such as the types of coarse aggregates with different elastic moduli, different mixing methods for aggregates and fibres (steel fibre, basalt fibre and polypropylene fibre) and two fracture test methods, on the fracture performance of concrete. LC30 all-lightweight shale ceramsite (SC) concrete was regarded as the benchmark. SC was replaced with limestone gravel at a volume ratio of 30% and changed into gravel lightweight concrete. Forty-two three-point bending notched beams and 42 single-side double-notched beams were firstly fabricated, then type I tensile test and type II shear test were conducted. The load (P, kN)–deflection (δ, mm) curves and load (P, kN)–crack mouth opening displacement (CMOD, mm) curves were obtained via type I test, and P–δ curves were obtained via type II test. The effects of aggregates and fibres on type I and II failure modes were analysed, and the influence on the initial fracture toughness, unstability fracture toughness and fracture energy was evaluated. The linear relationships between fracture energy and unstability fracture toughness were determined by type I test, and the relations amongst the initial and unstability fracture toughness and shear force were identified by type II test. Comparative analysis shows that the influence of high-modulus aggregates and fibres on the fracture performance is considerable. The peak load of type II test is an order of magnitude larger than that of type I test, and the peak displacement is also much larger. The failure characteristics of type II test have the composite features of type I and II fracture tests. Some kind of ratios exist between the initial and unstability fracture toughness of types II and I. However, the extent of type I impact on type II is difficult to quantify.

Shear performance of fibers-reinforced lightweight aggregate concrete produced with industrial waste ceramsite-Lytag after freeze-thaw action

Freeze-thaw (F-T) is an environmental hazard to concrete, severely reducing the mechanical properties and durability of concrete structures. The quantitative calculation of the shear performance of lightweight aggregate concrete (LWAC) after F-T action remains obscure. This study performed comprehensive research on basalt (BF)- and polyacrylonitrile fiber (PANF)-reinforced LWACs after F-T action, which can provide the basis for durability design. Compared with plain LWAC, specimens with fiber reinforcement showed a lower reduction in the relative dynamic elastic modulus (RDEM) and shear strength, and the shear strength and length-diameter rate of the fibers were the main impact factors. From the tests, 1.0% BF and 1.5% PANF are suggested as optimal for F-T resistance enhancement. Corresponding models are proposed to predict the changing tendencies of the shear strength, peak shear strain and shear modulus of LWACs after F-T cycles, considering the impact fibers and the environmental parameters. A statistically stochastic model was applied to predict the shear stress-strain curves after F-T action, and the calculation results match the test results well. The evaluation criteria in the standard are unsafe for LWAC F-T durability design. The F-T service life evaluation based on strength degradation could be advantageous in terms of the sustainable development of LWACs in an F-T environment.

Shear performance of lightweight aggregate concrete with and without chopped fiber reinforced

This paper presents a study on the shear performance of two different high-performance chopped fibers (basalt fiber and polyacrylonitrile fiber) employed to reinforce lightweight aggregate concrete. Environmentally friendly supplementary cementitious materials, fly ash and silica fume, are used to substitute a part of cement. Around 21 UDVW specimens are designed to test shear performance. The relationships between the shear strength and the cube compressive strength, splitting strength, flexural strength, and specific strength are established. Although the addition of the fibers does not change the shear failure morphologies, but could change the development direction of the cracks. Moreover, the fibers increase both the peak shear stress and the peak shear strain, and corresponding calculation models are proposed to predict these properties using the coefficient of shear strength enhancement βs. When the fiber content reaches 1% and 1.5%, the normalized shear stress–strain compared wrapped that of plain specimen notably. With an increase in the fiber content, the peak secant shear modulus decreases slightly, whereas the initial tangent shear modulus increases. Moreover, calculation methods are established to compute the peak secant shear modulus and the initial tangent shear modulus. The calculated results of several equations in this study present excellent agreement with the test results.

Mechanical properties and microstructure of lightweight aggregate concrete with and without fibers

The effects of several factors such as dry apparent density, water-to-binder ratio, properties of expanded shale aggregates, and fiber volume fraction, on the mechanical properties of lightweight aggregate concrete (LWAC) were experimentally investigated. Performance of LWAC were characterized through compressive strength, splitting tensile strength and flexural strength. This paper characterizes the morphology and microstructure of lightweight aggregate and two types of interfacial transition zone (ITZ) by using scanning electron microscopy (SEM). More than 40 different LWAC mixtures included five different expanded shale aggregates and two types of fiber were designed and fabricated, exhibited 28-day compressive strength from 47 to 86 MPa for dry apparent density of 1720–1940 kg/m3, respectively. The test results shown that both water-to-binder ratio and lightweight aggregate properties have significant effects on the LWAC. Crushed shale aggregate with dense shell and low absorption was recommended. The addition of fiber had a slight impact on compressive strength but resulted in significant increases in splitting tensile strength and flexural strength. The maximum increase in strength was achieved at a volume fraction of carbon fibers of 0.9%. Furthermore, microstructure investigation revealed that a slight wall effect occurred in the ITZ of lightweight aggregate with a dense shell and low water absorption.

Effect of palm oil fuel ash on compressive strength of palm oil boiler stone lightweight aggregate concrete

Both palm oil fuel ash (POFA) and palm oil boiler stone (POBS) are by-products which has been continuously generated by local palm oil mill in large amount. Both by products is usually disposed as profitless waste and considered as nuisance to environment. The present research investigates the workability and compressive strength performance of lightweight aggregate concrete (LWAC) made of palm oil boiler stone (POBS) known as palm oil boiler stone lightweight aggregate concrete (POBS LWAC) containing various content of palm oil fuel ash. The control specimen that is POBS LWAC of grade 60 were produced using 100% OPC. Then, another 4 mixes were prepared by varying the POFA percentage from 10%, 20%, 30% and 40% by weight of cement. Fresh mixes were subjected to slump test to determine its workability before casted in form of cubes. Then, all specimens were subjected to water curing up to 28 days and then tested for its compressive strength. It was found out that utilizing of optimum amount of POFA in POBS LWAC would improve the workability and compressive strength of the concrete. However, inclusion of POFA more than optimum amount is not recommended as it will increase the water demand leading to lower workability and strength reduction.

Performance of lightweight aggregate and self-compacted concrete-filled steel tube columns

The aim of this paper is to investigate the performance of Lightweight Aggregate Concrete Filled Steel Tube (LWCFST) columns experimentally and compare to the behavior of Self-Compacted Concrete Filled Steel Tube (SCCFST) columns under axial loading. Four different L/D ratios and three D/t ratios were used in the experimental program to delve into the compression behaviours. Compressive strength of the LWC and SCC are 33.47 MPa and 39.71 MPa, respectively. Compressive loading versus end shortening curves and the failure mode of sixteen specimens were compared and discussed. The design specification formulations of AIJ 2001, AISC 360-16, and EC4 were also assessed against test results to underline the performance of specification methods in predicting the compression capacity of LWCFST and SCCFST columns. Based on the behaviour of the SCCFST columns, LWCFST columns exhibited different performances, especially in ductility and failure mode. The nature of the utilized lightweight aggregate led to local buckling mode to be dominant in LWCFST columns, even the long LWCFST specimens suffered from this behaviour. While with the SCCFST specimens the global buckling governed the failure mode of long specimens without any loss in capacity. Considering a wide range of column geometries (short, medium and long columns), this paper extends the current knowledge in composite construction by examining the potential of two promising and innovative structural concrete types in CFST applications.

Application of a combination of municipal solid waste incineration fly ash and lightweight aggregate in concrete

This paper highlights significant findings from focusing on developing a sustainable lightweight aggregate (LWA) concrete, which replaced Portland cement partially with municipal solid waste incineration fly ash (MSWI FA) and all of the conventional coarse aggregate with LWA sintered by MSWI FA, shale, and sludge. A series of four experiments, differing in dosage of MSWI FA and aggregate, were conducted for this project. The results of this study generally showed that appropriate amount of MSWI FA substitution for cement has no significantly lowered the compressive strengths of LWA concrete, while it can lower the oven-dry density and the thermal conductivity. The optimum performance of LWA concrete (after 28 days of curing) is as follows: (1) slump flow of 700 mm, (2) compressive strength of 30.14 MPa, (3) dry apparent density of 1.66 g/cm3, (4) thermal conductivity of 0.73 W (m K)−1; the mixture ratio of LWA, fly ash, cement, and fine sand is 3.0: 0.1: 0.9: 2.0 based on dry weight. Meanwhile, the results of leaching test are much lower than the concentration limits of hazardous constituents of hazardous waste identification standard (GB/T 5083.3-2007) and landfill standard (GB16889-2008).

The Impact of Steel Fiber on the Performance of Lytag Lightweight Aggregate Concrete

The article studies the impact of steel fiber on the performance of lightweight aggregate concrete,including compressive strength, flexural strength, modulus of elasticity and impact toughness. The experimental studies show that steel fiber has little effect on the compressive strength of lightweight aggregate concrete, however, it can improve the pattern obviously. With the increasing of steel fiber content, the flexural strength and impact toughness of concrete increases. With the increasing of steel fiber content ,the elastic modulus of concrete also increases. The studies of this paper provide a certain technical references with the future research of steel fiber reinforced lightweight aggregate concrete.

Permeability of Lightweight Aggregate Concrete with Mineral Admixture

This paper presents an experimental study on the permeability and the pore structure of lightweight concrete with fly ash, zeolite powder, or silica fume, in comparison to that of normal weight aggregate concrete. The results showed that the mineral admixtures can improve the anti-permeability performance of lightweight aggregate concrete, and mixed with compound mineral admixtures further more. The resistance to chloride-ion permeability of light weight concrete was higher than that of At the same strength grade, the anti-permeability performance of lightweight aggregate concrete is better than that of normal weight aggregate concrete. The anti-permeability performance of LC40 was similar to that of C60. Mineral admixtures can obviously improve the pore structure of lightweight aggregate concrete, the total porosity reduced while the pore size decreased.

Effect of lightweight aggregates on the mechanical properties and brittleness of lightweight aggregate concrete

The influence of volume fraction and aggregate properties on the mechanical performance of lightweight aggregate concrete (LWAC) were studied. A new Shape Index that described the shape characteristics of lightweight aggregate (LWA) has been proposed and its effects on resulting LWAC were evaluated. Test results substantiate that the proposed Shape Index had a great influence on the mechanical properties of LWAC.Crack development, failure characteristics and stress strain curves of LWAC were studied and the concept of the proportional strain ratio was introduced to evaluate the brittleness of LWAC. Test results showed that higher volume content of LWA resulted in a more brittle failure. It was also found out that for similar concrete strengths, LWAC was comparatively brittle than normal weight concrete (NWC).

Performance of lightweight aggregate concrete containing slag after 25 years in a harsh marine environment

This paper reports the results of a study on concretes containing lightweight aggregate (LWA) retrieved from the tidal zone of a marine exposure site. In terms of chloride resistance, the LWA concrete performed equivalently to similar concretes of the same age produced with normal density aggregate that were retrieved from the same site 2years earlier. The partial replacement of Portland cement with slag led to substantial reductions in chloride penetration and the chloride diffusion coefficient. However, at w/cm≥0.50, the incorporation of slag resulted in increased surface deterioration (scaling) attributed to freezing and thawing. Concrete with LWA, silica fume and w/cm=0.33, showed better-than-expected performance with regard to resistance to chloride-ion penetration and it is speculated that this may be partly attributed to “internal curing” provided by the LWA which reduces the impact of self desiccation. Further studies are needed to confirm this phenomenon.