Strength Of Foamed Concrete Research Articles

Resourceful Utilization of Cow Hair in the Preparation of Iron Tailing-Based Foam Concrete.

Cow hair, a by-product of tannery waste, is usually stockpiled on a large scale as waste, which leads to serious environmental impacts. In this paper, cow hair was used as a reinforcement fiber to improve the mechanical strength of iron tailing-based foam concrete. The effects of the amount of cow hair fiber on the apparent density, compressive strength, and flexural strength of foam concrete were investigated by a series of characterization methods. Meanwhile, Image-Pro Plus software was used to analyze the porosity, average pore size, roundness, and other parameters of the specimens with different amounts of cow hair fiber. Results revealed that a proper amount of cow hair fiber can form a stable three-dimensional network structure inside the foam concrete and promote a uniform distribution and size of the pore structure inside the test piece. This could effectively improve the compressive strength, flexural strength, and crack resistance of the foam concrete, and when the fiber content was 0.2 wt%, the foam concrete exhibited the best mechanical properties, with a compressive strength of 11.19 MPa and a flexural strength of 3.58 MPa. The present work was in agreement with the strategic objective of resource recycling and solid waste utilization, which was conducive to the development of the circular and green economy.

The Effect of The Use Of Foam Agent and Clam Shell Powder on The Compressive Strength and Absorbency of Concrete

A foaming agent is a concentrated solution of surfactant material that must be dissolved in water before mixing with other concrete material. The foaming agent is used to produce lightweight concrete with a density is £ 1.900 kg/m³. Using foam agents may affect the compressive strength and absorbency of the concrete. Hence, adding clam shells is expected to improve the compressive strength of the foam concrete. In addition, it is also essential to investigate the effects of utilizing foam agents and clam shells on the density of the foam concrete. Nine concrete mixes namely 1 variation of standard concrete, four variations of concrete mixes with foam agent, and four variations of concrete with foam agent and calm shell have been studied to investigate the parameters.The variation of foam agents in the eight concrete mixes were 5%, 10%, 15%, and 20% by water weight. The last four variations contained clamshell of 5% by weight of fine aggregate. The foam agent wasfoamingduced by mixing with a ratio of water and foam agent of 40:1. The experimental results show that at the variation of 20% foam agent, the density reduced by 34.55% and 26.89% for foam concrete with and without clam shell compared to normal concrete. I contrast, adding clamshell also lowered down the compressive strength of foam concrete by 79.86% and 74.96% for the variations. Meanwhile, the highest absorption rate of 1.65% or increased about 6.45% from normal concrete occurred at a variation foam agent of 15% mixed with clamshell. It was concluded that the use of clam shell in the foam concrete seems to decrease the strength of the foam concrete. However, in terms of density, the use of clam shells benefits foam concrete by lowering the self-weight of concrete.

Influence of self-ignition coal gangue on properties of foam concrete with steam curing

This paper aims to study the influence of coal gangue (CG) on compressive strength, drying shrinkage, air void structure, and microstructure of foam concrete with steam curing. Coal gangue foam concrete (CGFC) mixtures were prepared by introducing CG at levels of 10−50 % to replace ordinary Portland cement. Steam curing was applied to increase the early-age strength of CGFC. Experimental results showed that with the increase of CG dosage from 10 % to 50 %, the 1 d compressive strength of foam concrete was increased firstly and then decreased. With the same level of bulk density, the incorporation of 30 % CG reached the highest 1 d strength. The addition of 50 % CG decreased the drying shrinkage by 18.8 % for steam-cured samples. Air bubbles and porosity of foam concrete were coarsened by the steam curing but refined by the incorporation of CG. The mineral compositions results indicated that the steam-curing could accelerate the hydration of cement and the pozzolanic reaction of CG, being contribute to the improvement of early-age compressive strength. The scanning electron microscope images exhibited the formation of micro-cracks in steam-cured foam concrete samples which was alleviated by adding CG. Therefore, the utilization of coal gangue in foam concretes benefits both the environmental pollution control and the factory manufacture of lightweight wall panels for building structures.

Preparation and performance analysis of recycled PET fiber reinforced recycled foamed concrete

Construction waste and waste fabric are two major types of solid waste that lead to landfill issue and environmental pollution. Considering the need for more efficient handling method by simultaneously handling both solid waste materials, this study reports an innovative solution to transform waste concrete and waste polyester fabric into environmentally friendly product, recycled foamed concrete (RFC). The dry density, compressive strength, water absorption, frost resistance and chemical erosion resistance of plain RFC (PRFC), PET fiber reinforced RFC (PETRFC) and recycled PET fiber reinforced RFC (RPETRFC) were evaluated. The results indicated that the added recycled powder (RP) can improve the compressive strength of foam concrete. Moreover, the addition of PET fiber (0.1 wt.% content and 6 mm length - optimum) improved the compressive strength (especially the early strength) and durability but had no significant effect on dry density and water absorption. Recycled PET fiber presented a better enhancement effect than PET fiber. The dry density and 28-day compressive strength of RPETRFC were 5.2% and 5.1% higher than those of PETRFC, respectively, and water absorption was 10.7% lower than that of PETRFC. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis indicated that recycled PET fiber had a multifilament structure, which can effectively improve the pore structure of RFC without changing the hydration mechanism. This study demonstrates a new direction for recycling waste concrete and polyester fabric with excellent economic and environmental benefits, and the findings provide reference for the development of lightweight RFC with improved physical properties and durability.

Study on Influence Factors of Compressive Strength of Low Density Backfill Foamed Concrete Used in Natural Gas Pipeline Tunnel

Foamed concrete is mostly used for backfilling of long-distance tunnels and compressive strength is an important technical index to control the quality of foamed concrete. The influence factors on compressive strength of low-density foamed concrete were obtained by the single factor test method based on the targeted dry density and compressive strength. The results show that the HT composed of pollution-free animal protein oil and vegetable oil is an efficient foaming agent and can produce stable foams. The cementation ability of cement can be fully expressed when a water to cement ratio of 0.45~0.5 is employed, making foamed concrete have a compressive strength higher than 2 MPa. The foam content is inversely proportional to the compressive strength and dry density of foamed concrete, and the volume ratio of slurry to foam should be 2:1~3:1. The content of fly ash is also inversely proportional to the compressive strength but positively proportional to the dry density. When the content of admixture is 40~55%, the compressive strength of foamed concrete with low density is not less than 2 MPa. The mixing proportion can be changed in the reasonable range to meet the requirements of different projects.

Properties of foam concrete with hydrophobic starch nanoparticles as foam stabilizer

This study proposes the use of hydrophobic starch nanoparticles (H-SNPs) as a foam stabilizer. Simultaneously, the properties of foamed concrete prepared by adding a foaming agent to H-SNPs are investigated. The experimental results indicate that the foam prepared using a combination of H-SNPs and synthetic surfactants (SS) has increased stability and improved density and viscosity. When H-SNPs and synthetic surfactants (HS-SS) were used as a foaming agent, foam drainage decreased by 8% after 5 min. After 28 days of curing, the compressive strength of foamed concrete containing H-SNPs increased from 2.35 MPa to 2.77 MPa. And the percentage of pores in the range of 100–500 μm increased to 63.2% implying that the addition of H-SNPs makes the pore size distribution narrower, the pore size smaller. Meanwhile, foam concrete's shrinkage and uniformity are improved. There are two possible explanations. One is that due to the chemical reaction between the carboxyl group of citric acid and the hydroxyl group of starch, the starch changed from hydrophilicity to hydrophobicity. As a result, the H-SNPs can be evenly adsorbed onto the foam's surface. Another advantage is that H-SNPs can be used to fill the pores between the foam and the cement body, thereby increasing the strength of foam concrete.

High temperature effect of foamed concrete under equal displacement increment triaxial cyclic compression

Foamed concrete (FC) has been extensively used for its lightweight, good thermal insulation, and sound insulation properties. It has gained broad investigations in the past decades, but the data of triaxial cyclic compression tests are lacking. In this study, triaxial cyclic tests were conducted under different confining pressures (0 MPa, 0.3 MPa, 0.5 MPa, 0.8 MPa) with four temperature treatments (25 °C, 100 °C, 200 °C, 300 °C) to obtain the failure modes and stress-strain curves, analyze the compressive strength, residual strength, elastic modulus and brittleness index, explain the fracture mechanism and damage evolution of FC from the perspective of energy dissipation. Furthermore, the strength prediction model of FC was proposed and its yield criterion was verified. The results show that the damage pattern of FC was significantly influenced by confining pressure and the mechanical parameters were more sensitive to temperature. The energy density and damage increased linearly with the number of cycles, and the dissipated energy accounted for a large proportion under low confining pressure or high temperature. The Crushable-foam yield criterion had good applicability to FC, and thermal damage decreased the hydrostatic yield strength of FC.

Properties and modification of sustainable foam concrete including eco-friendly recycled powder from concrete waste

Reusing recycled powder (RP) including recycled concrete powder (RCP) and recycled mortar powder (RMP) as an eco-friendly alternative binder benefits the reclamation of construction waste and reduces the cement demand. Considering that foam concrete (FC) which contains high-volume cement and supplementary cementitious material (SCM) has been largely used in building engineering owing to its low density and good thermal insulation performance, and thus, substituting RP for partial cement in preparing FC is more sustainable. This work studied the influence of RP type and replacement on the performance of newly-made FC, and some feasible modification methods for improving the performance of RP blended in FC were further provided. A series of micro and macro tests were conducted. The results show that the utilization of RP has no distinct impact on the dry apparent density, thermal conductivity and porosity of its prepared FC. When the RP replacement rate is below 15%, the compressive strength of FC containing RP is slightly lower than that of FC without RP, while the compressive strength of FC decreases significantly as high-volume RP incorporates. Incorporating polyvinyl alcohol (PVA) fiber decreases the drying shrinking of FC containing RP, and the RP-prepared FC incorporating 0.3% PVA fiber has lower drying shrinkage and higher strength than that without fiber incorporation. The addition of metakaolin (MK) improves the mechanical strength of RP blended in FC, and the compressive strength increases by 32.9–34.9% as 10% MK incorporates.

Influence of fine aggregate on strength of foam concrete

This study aims to investigate the foam concrete having a unit weight from 800 kg/m³ to 1200 kg/m³. After calculating the mixture proportion based on the empirical methods, the experiments were conducted in the laboratory to determine the mechanical properties of foam concrete using fine sand. Besides, the foam concrete using coarse sand was also cast as a reference. The results show that the compressive strength and flexural tensile strength of foam concrete using fine sand were higher than those of reference concrete corresponding to the same mixture proportion. As a consequence, the utilization of abundant fine sand for the production of the insulated concrete structure or lightweight concrete bricks can prevent the exhaustion of coarse sand.

Utilisation of Oil Palm Fibre Biomass Waste as Additives in Foamed Concrete

Worldwide, the construction industry has acknowledged the future demand for lightweight construction materials, with high workability, self-compacting, and environmentally friendly. Given this demand, recent innovative material namely foamed concrete (FC), has been found to reduce normal concrete’s weight potentially. However, while FC made with Ordinary Portland Cement has good compressive strength, other characteristics such as tension are relatively weak given the number of micro-cracks. Therefore, the study focused on the potential use of oil palm fibres in FC regarding their durability and mechanical properties. Notably, one of the major issues faced in the construction of reinforced FC is the corrosion of reinforcing steel which affects the behaviour and durability of concrete structures. Hence, in this study, oil palm fibres were added to improve strength and effectively reduce corrosion. Five types of fibre generated from oil palm waste were considered: oil palm trunk, oil palm frond, oil palm mesocarp and empty fruit bunch consisting of the stalk and spikelets. Specimens with a density of 1800 kg/m3 were prepared in which the weight fraction of the fibre content was kept constant at 0.45% for each mixture. Testing ages differed in testing and evaluating the parameters such as compressive strength, flexural strength, tensile strength, porosity, water absorption, drying shrinkage and ultrasonic pulse velocity. The results showed that the incorporation of oil palm fibre in FC helped reduce water absorption, porosity and shrinkage while enhancing the compressive, flexural and tensile strength of FC.

The stability and durability of silt-based foamed concrete: A new type of road engineering material

This paper implements four types of tests under three designed wet densities, including drying-wetting cycles test, freeze–thaw cycle test, water stability test, and dry shrinkage test, to analyze the strength change law of silt-based foamed concrete after a specified age or a number of cycles. Test results showed that compressive strength of silt-based foamed concrete was not adversely affected by external environment during 90 days’ saturation period. Phenomenon of dry and shrinkage for silt-based foamed concrete mainly occurred at the first 7 days and tended to be stable within a month, the subsequent dry shrinkage phenomenon was not significant. After 50 times of drying-wetting cycles, the loss rate of foamed concrete became small. Specimens presented great performance of drying-wetting cycles. After 30 times of freeze–thaw cycles, the compressive strength, splitting and tensile strength of foamed concrete decreased slightly. Specimens presented good performance of freeze–thaw cycles. Therefore, the stability and durability of silt-based foamed concrete are considered great and meet the needs of road engineering construction.

Collaborative disposal of multisource solid waste: Influence of an admixture on the properties, pore structure and durability of foam concrete

Solid waste building material treatment is an essential means of disposal and an active research area. Despite this, the multisource characteristics, large volumes and complex compositions of solid waste necessitate new requirements for its treatment. In this paper, a typical resource-based coastal city is considered the research object. Fly ash (FA), furnace slag (FS) and mineral powder (MP) are taken as samples to investigate the influence of admixtures on the properties, pore structure and durability of foam concrete by three-factor and three-level orthogonal tests. Results indicate that foam concrete with different admixtures can have various mechanical and thermal insulation properties. The compressive strength of foam concrete can increase to 3.90 MPa, and its thermal conductivity can reach 0.1347 W/M·k. MP has the largest apparent effect on the compressive strength, while FS has the most obvious impact on the thermal conductivity. The durability analysis shows that the number of freeze-thaw cycles foam concrete can withstand is 25–100 cycles. The collaborative disposal of multisource inorganic solid waste has high potential for being applied as inner partition walls and thermal insulating components in buildings. This paper provides valuable guidance for the sustainable and clean utilization of multisource inorganic solid waste.

Assessment of the Use of Polypropylene Fiber Reinforced Foam Concrete as a Subgrade Material for the China Railway Track System (CRTS) III Slab Ballastless Tracks

This paper presents the application and the development of foam concrete (FC) to replace the traditionally used subgraded materials (typically compacted soil or granular earth rock) in high-speed railway by using cement to sand ratio of 2:1 with a target density of 500 to 700 kg/m3 and by adding polypropylene (PP) fibers with 0.25% and 0.40% by volume to improve the properties of FC. The mechanical properties were evaluated and tested in the laboratory in accordance with ASTM standard method, including compressive strength, tensile strength, modulus of elasticity and Poisson’s ratio, and dynamic strength. In addition, the numerical model investigates the performance and analyzes the effect of applying the full cross-section PP fiber reinforced FC in slab ballastless track, under different thicknesses, on the dynamic response of the whole structure, and then compares them with that of the traditional structure. The results indicate that the strength of FC with a density of 500 to 700 kg/m3 can meet the requirements of static and dynamic loading conditions of railway earth structure. But the density of 600 to 700 kg/m3 shows good strength stability under different curing states. In addition, adding 0.25% PP fiber is an optimal volume that can significantly improve mechanical properties. The prediction of the model shows that FC at a density of 600 kg/m3 by adding PP fibers of 0.25% at a thickness of 1.5 m can reduce the stress and vibration of the track structure better than that of the traditional structure; this indicates a long-term maintainance stability of the subgrade bed.

Resource Utilization of Waste Mud -- Preparation and Properties of Foamed Concrete

The compressed and dehydrated mud was made into filter cake, and then fly ash, silica fume and cement were added to it to prepare foamed concrete with sodium α-olefin sulfonate as foaming agent. By analysing the changing characteristics of the compressive strength, apparent density, water absorption and microstructure of the foam concrete, the key mechanism of making the foam concrete was analysed in depth. The results show that mud filter cake can improve the comprehensive performance of foamed concrete. The best mix ratio is 20% of mud filter cake, 50% of cement addition, 20% of fly ash, 10% of silica fume, 0.55 of water cement ratio and 55% of foam volume. The compressive strength of foam concrete is 1.6MPa and the apparent density is 660.26kg/m3. The water absorption rate is 23.73%, which accords with China Construction Industry Standard JG / T266-2011. Proper addition of mud filter cake can improve the pore structure and cementing material matrix of foamed concrete, and enhance the strength of foamed concrete. However, too much addition will produce connected pores and cracks, and reduce compressive strength. The results can provide theoretical basis and technical reference for mud resource utilization.

Optimization of Cuttlefish Bone Towards Compressive Strength of Foam Concrete

Development and testing of other foam concrete materials, as well as the inclusion of a marine-based filler, cuttlefish bone powder, may be one of the most advanced products suitable for cementitious materials to be added in concrete to provide a sustainable environmentally friendly alternative solution on construction industry in Malaysia. Cuttlefish bone will have some advantages and benefits in foam concrete since it contains high amounts of calcium carbonate, which is believed can improve the concrete’s strength and encourage foam concrete to achieve an early strength. The objectives of this research is to determine the optimum percentage of cuttlefish bone additive towards increasing the strength properties of foam concrete. In this research, there were 42 foam concrete cube samples prepared, each group of samples containing different amounts of cuttlefish bone additive (1%, 2%, 3%, and 4%). All the samples were tested for compressive strength at 1, 3, and 7 days of age. According to the findings, an improvement in the foam concrete when the cuttlefish bone additive content from 1% to 4% added which result in the enhancement of the behavior of foam concrete. In addition, this research reveals that cuttlefish bone additive has better characteristics to normal OPC, making it an effective addition to concrete.

Studies on influence of characteristics of surfactant and foam on foam concrete behaviour

This paper describes an extensive laboratory-based investigation conducted to evaluate the relative performance of foam produced with two different synthetic surfactants namely Sodium lauryl sulphate (SLS) and Nonylphenol ethoxylate (NPE) along with an additive Carboxymethyl cellulose sodium salt (CMC) for use in foam concrete. The different essential characteristics of foam and surfactants such as initial foam density, foam stability, average bubble size and viscosity of surfactant solution are investigated in the present study through systematic experimental design based on response surface methodology. Further, based on studies on microstructure of foam concrete, it is found that selection of surfactant and CMC concentration have significant influence on foam characteristics and hence on the air void size distribution of foam concrete. In addition, the dependence of the compressive strength and water permeation characteristics of foam concrete on the air void size parameters of concrete is also investigated. Experimental outcomes indicate that increase in surfactant concentration from 3% to 6% results in 24%–44% reduction in median air void diameter in concrete which eventually led to 29%–37% enhancement in compressive strength of foam concrete mixes. In the same line, addition of CMC to surfactant solution enhances viscosity of surfactant solution significantly and thereby results in improvement of foam microstructure, concrete air void microstructure and eventually improves compressive strength of foam concrete. Further, improved microstructure with smaller air voids in foam concrete with NPE + CMC results in 10%–25% relatively higher compressive strength than SLS + CMC foam concrete mixes.

Evaluation of Suitability of Carboxymethyl Cellulose in Performance Improvement of Sodium Lauryl Sulfate Foam and Compressive Strength of Foam Concrete

Abstract Currently, foam concrete is commonly used for various construction applications such as partitions, filling grades, road embankment infills, and sound and heat insulation. It is to be noted that the foam production parameters have significant influence on the cellular structure of foam concrete, which governs the material properties of concrete. Hence, in an attempt to improve the foam quality, the present work focuses on evaluation of the suitability of viscosity enhancing agent carboxymethyl cellulose (CMC) in performance improvement of foam produced with surfactant sodium lauryl sulfate (SLS) for use in foam concrete production. Firstly, the influence of the addition of CMC on behavior of foam produced with surfactant SLS was studied by evaluating essential characteristics such as foam density, foam stability, and viscosity of surfactant solution. As a next step, the microstructure of foam and its behavior in cement slurry and mortar at the optimized concentrations of SLS and CMC were studied. Experimental studies revealed that the addition of 0.2 % CMC to 2.5 % SLS surfactant solution resulted in a 134 % increase in viscosity of surfactant solution, which eventually resulted in tremendous improvement in foam quality in terms of 34 % reduction in foam drainage (at the 5th minute after foam generation) and 22 % reduction in larger size foam bubbles (D90). Furthermore, as the air void microstructure of foam concrete is dependent on the foam bubble sizes, the reduction in foam bubble sizes resulted in 20 % enhancement in compressive strength of foam concrete. The addition of CMC is also found to affect the workability of foam concrete mixes, which is evident from the reduction in flow spread and the increase in flow time. Also, as the foam has retarding properties, the increase in foam content is found to increase the demolding time requirement of foam concrete specimens.

Karakteristik Beton Busa Akibat Variasi Foamed dan Subsitusi Fly Ash Terhadap Semen

Foam concrete is a concrete technology that is applied to buildings. The advantage of foam concrete is that it is lightweight and fast in building work. The use of foamed in foam concrete reduces the density of foam concrete. Substitution of fly ash for cement can increase the compressive strength of foam concrete. The variations of foamed used in this study were 30%, 40%, and 50%. The substitution of fly ash for cement in this study was 0%, 5%, and 10%. In the specific gravity test, the smallest value was 1,156 kg / m3 resulting from a variation of 50% foamed and 0% substitution of fly ash for cement, while the largest weight was 1,670 kg / m3 resulting from 30% foamed variation and 10 fly ash substitution. % against cement. In the compressive strength test at 28 days of concrete, the highest value was obtained with a value of 2.573 N / mm2 resulting from 30% variation of foamed and 5% substitution of fly ash for cement, while the lowest compressive strength was 1.986 N / mm2 resulting from variations of foamed 30 % and 10% substitution of fly ash for cement. The optimum composition of foam concrete in this study was found in a mixture with 40% foamed variation and 5% fly ash substitution for cement with a value of 2,312 N / mm2 and a specific gravity of 1438 kg / m3. The optimum use of fly ash is obtained at a substitution percentage of 5% for cement. Foam concrete using styrofoam and polypropylene fibers is good for non-structural elements in buildings such as wall panels. Keywords: Light weight concrete, foamed concrete, fly ash

Effect of Water and Admixture on Foam Concrete Properties

The paper presents mathematical modeling of additives and water’s effect on foam concrete’s compressive and flexural strength at 28 days of normal hardening. The requirements of GOST 10180-2012 determined the compressive and flexural strength of foam concrete. The initial composition of the foam concrete mix was calculated using the absolute volume method.Results received first-order regression equations. The compressive strength and flexural strength of foam concrete depended on the relations from and the image surface expression and objective function for the regression equations. The optimal value obtained: compressive strength = 8.075 MPa and flexural strength 1.087 MPa.

Effect of Coal Gangue Grain Size on Strength of Foam Concrete

This work shows that the grain size of coal gangue has affects on the strength of foam concrete with coal gangue. Coal gangue was crushed and separated into three grades sand according to the size which were 0.16-0.6mm, 0.6-2.5mm and 2.5-5mm. Then these coal gangue sand was used to manufacture foam concrete with a density of about 850kg/m3. The compressive, flexural strength, water absorption and softening coefficient of coal gangue foam concrete were tested. The results show that compressive strength of foam concrete exhibits a monotonic decreasing while coal gangue content increases and the decreasing rate would accelerate with the increasing of grain size. And the water absorption increased with the coal gangue content and grain size increasing. Small size coal gangue could improve the water absorption resistance. The coal gangue foam concrete is a water-resistant material and the softening coefficient is above 00.85, when the diameter of coal gangue fine aggregate is below 2.5 mm.