Foam Concrete Research Articles

Analysis of the Influence of Incorporating Different Thermal-Insulating Materials into the Sub-Ballast Layers

Adverse climatic conditions, particularly excessive water and frost, necessitate the design of thick protective sub-ballast layers when dealing with frost-susceptible subgrade surfaces, especially when using standard natural materials (crushed aggregate or gravel–sand). Given the current preference for conserving natural construction materials and promoting sustainable development in the dimensioning of sub-ballast layers, it is advisable to incorporate various thermal insulation, composite, or suitable recycled materials in their design. Therefore, the paper analyses the impact of incorporating different thermal insulation materials (including extruded polystyrene, Liapor, Liapor concrete, and composite foam concrete) into sub-ballast layers. As part of the experimental research, these modified sub-ballast layers were constructed on a real scale in the outdoor environment of the University of Žilina (UNIZA) campus. They were subsequently compared in terms of their thermal resistance to climatic loads. The research results demonstrate that extruded polystyrene provides the optimal thermal insulation effect in modified sub-ballast layers, which was subsequently used in the numerical modelling of railway track structure freezing under different climatic loads.

THE EFFECT OF TRAVERTINE WASTE ON THE STRENGTH AND INSULATION PROPERTIES OF FOAM CONCRETE

Abstract Incorporating waste additives into foam concrete mixtures is a promising route to develop environmentally-friendly concrete production with tailored thermos-mechanical properties. In this paper, the effects of various fabrication parameters of foam concrete, including the type of waste additive, water/binder ratio, density of mixture, and incorporation of glass fibers were investigated. Foam concrete samples were fabricated using fly ash and travertine wastes, and the variations in their flexural strength, compressive strength, and thermal conductivity using various concrete mixture designs were measured. The obtained results show that foam concrete with fly ash additive tends to have higher compressive strength and thermal conductivity than foam concrete with travertine waste. However, the latter exhibits better thermal insulation properties, which tend to improve by adding glass fibers. This work defines the outlines for exploring the use of harmful wastes in fabricating foam concrete. It offers guidelines for developing improved foam concrete mixtures with tailored thermos-mechanical properties.

Study on the Influence of Fibers to the Physical Mechanical Properties of Foam Concrete

Foam concrete has been widely used in building, infrastructure and fire prevention fields because of its lightweight, excellent heat and sound insulation performance. However, due to its high porosity, the compressive strength of foam concrete is usually low, which limits its application in some high-strength structures. In order to solve this problem, researchers improve the mechanical properties of foam concrete by adding different types of fiber materials. This paper summarizes the research progress of fiber on the performance of foam concrete, and analyzes the influence of different types of fiber (such as polypropylene fiber, basalt fiber, polyvinyl alcohol fiber, etc.) on the performance of foam concrete. The research shows that adding proper amount of fiber into foam concrete can effectively improve the mechanical, durability, dry shrinkage and other properties of foam concrete.

An Experimental Study on Foam Concrete By Partial Replacement of Cement using Rice Husk Ash and Silica Fumes

A type of lightweight aerated concrete called foam concrete lacks coarse particles, making it comparable to aerated mortar. Foam concrete is created when slurry and pre-formed foam are combined. The foam's job is to create air pockets in the slurry made of cement. The foam is made separately with a foam generator by diluting the foaming ingredient with water and aerating it. The slurry forms a shell surrounding the bubbles of foam, and as the foam begins to break down, the paste's strength keeps it in place around the air holes. The ratio of water to cement (w/c) typically varies from 0.4 to 1.25. As the quantity decreases, the foam concrete mixture becomes excessively rigid, which breaks the bubbles, However, when the combination's water content increases, it becomes too thin to support the bubbles, which causes the bubbles to separate from the mixture. You can make foam concrete with any dry density between 300 and 1850 kg/m3. In this experiment, there are two foam concrete mixtures created using silica fumes and rice husk ash, and efforts have been produced to choose the foam concrete mix's proportions. A collection of 36 cube specimens is created and subjected to mixture testing. Following this, their actual state (density) and particular structural (compressive strength) qualities are examined, with the findings being reported. Important terms: Foam Concrete, Foaming Agent, Rice Husk Ash, Silica Fumes, Density.

The Impact of Production Techniques on Pore Size Distribution in High-Strength Foam Concrete

The Impact of Production Techniques on Pore Size Distribution in High-Strength Foam Concrete

Precision assessment of the machine learning tools for the strength optimization of environmental-friendly lightweight foam concrete

Foamed concrete (FC) is increasingly used in modern construction due to its lightweight nature, superior thermal insulation, and sustainable properties. However, accurately predicting its compressive strength remains a challenge due to the complex interactions of its components. This study addresses this gap by employing advanced machine learning tools, including decision tree (DT), bagging, and AdaBoost, to develop predictive models for FC strength. The results provide a significant improvement in prediction accuracy, offering a reliable tool for optimizing FC design in construction applications. This research aims to streamline the sample creation process in the laboratory, minimize the waiting time for sample testing, and reduce the project's overall cost for researchers. A total of 149 data points were used from the literature to prepare a proper data set for modelling purposes. The modelling procedure used Python code via the Anaconda Navigator software. The statistical evaluation of the metrics, such as R2, MAE, and RMSE, along with the sensitivity analysis to check the impact of inputs and the 10-fold cross-validation method to validate the performance, were part of the presented research. Compared to the DT and bagging models, the results demonstrate that the AdaBoost model forecasts FC's compressive strength (CS) more accurately. The AdaBoost model gives the R2 value equal to 0.97, while DT and bagging show 0.86 and 0.94, respectively. The lower error result for the AdaBoost model and higher for both DT and bagging indicates the superior precision level of the AdaBoost approach. Finally, the graphical user interface (GUI) was designed utilizing the implemented models, which indicates the additional positive aspect of the presented study.

Low-Carbon Foamed Concrete Based on Alkali Residue and GGBS versus Conventional Foamed Concrete: Comparative Experimental Research

Low-Carbon Foamed Concrete Based on Alkali Residue and GGBS versus Conventional Foamed Concrete: Comparative Experimental Research

High-performance foam concrete containing multi-wall carbon nanotubes and ssDNA

High-performance foam concrete containing multi-wall carbon nanotubes and ssDNA

Study on the Properties of Basalt Fiber-Calcined Gangue-Silty Clay Foam Concrete for Filling Undermined Goaf Areas of Highways.

The collapse of surface goaf beneath highways can result in instability and damage to roadbeds. However, filling the goaf areas with foam concrete can significantly enhance the stability of the roadbeds while considerably reducing the costs of filling materials. This study analyzes the effects on destructive characteristics, mechanical properties, stress-strain curve features, and relevant metrics, while also observing the microstructure of basalt fiber-calcined gangue-silty clay foam concrete (BF-CCG-SCFC). The results indicate that the water-binder ratio significantly influences the cubic compressive strength, split tensile strength, and fluidity of BF-CCG-SCFC. Silty clay reduces the cubic compressive strength, split tensile strength, and fluidity of BF-CCG-SCFC. Conversely, an appropriate amount of calcined gangue and basalt fiber significantly increases the cubic compressive strength and split tensile strength, while decreasing fluidity. To satisfy the strength and fluidity requirements of the filler material in hollow areas, the optimal water-binder ratio for BF-CCG-SCFC is 0.55, the ideal mixing ratio of calcined gangue to silty clay is 2:2, and the basalt fiber content should be 1%. The study examines the influence of varying water-binder ratios, the combined proportions of calcined gangue and silty clay, and different basalt fiber contents on the elastic modulus, peak stress, and peak strain of BF-CCG-SCFC. Additionally, the water-binder ratio influences the matrix strength through the non-hydration reactions of doped particles, while gangue and clay induce a "gradient hydration effect" during the hydration process. The incorporation of basalt fibers enhances the mechanical interlocking between the fibers and the matrix.

Исследование физико-технических свойств легких бетонов на основе поризованного пенополистиролбетона

The results of a study of the composition of polystyrene concrete based on a study of its technical characteristics, are presented. The study was based on basic indicators, such as the water-binder ratio, the optimal ratio of the components of the composite binder, as well as the number of polystyrene foam granules in the composition of lightweight concrete. Using the scientific-experimental method, the ratio of its components was modeled. The study used standard materials for the production of lightweight concrete and polystyrene foam of various fractions. Based on the research carried out, the optimal ratio of components for the production of thermal insulating concrete was identified in accordance with regulatory documentation.

The Influence of the Solid Phase on the Properties of Foam Concrete

An overview of literary sources related to the formation and development of the technology of aerated concrete is given. It is shown and systematized in which directions scientific research aimed at improving their functional properties was conducted. It is noted that almost all researchers associate the dependence of the properties of porous concrete with the character of their porosity. The conducted analysis allowed the authors to hypothesize that the properties of aerated concrete are exclusively determined by the nature of the distribution of the solid phase, that is, by the nature of its structure. Determination of the influence of the solid phase and its nature on the properties of aerated concrete is devoted to experimental studies. They were conducted in two stages. At the first, when applying physical modeling, the effect of the total porosity and water consumption of the dry mixture on the change in the nature of the solid phase of the model was studied. Internal interfaces between structural elements are taken as characteristics of the solid phase - their total length and width. It is shown that the water consumption of the mixture has different effects on materials with a dense and porous structure. At the next stage of experimental research, the influence of the water consumption of the mortar mixture on its strength (strength of the matrix material) and the strength of foam concrete was studied. The initial rheological conditions of the formation of the structure were changed by changing the size and amount of filler, changing the amount of liquid and plasticizing additives. The results of the experiments confirmed that the initial rheological conditions have different effects on the materials of dense and porous structure. Under certain conditions, in materials with a porous structure (in foam concrete), an increase in the water-solid ratio leads to an increase in the strength of concrete. Which indicates that with such water consumption, more favorable conditions are created for the formation of a porous structure, which is reproduced on the character of the solid phase. The given results confirm the given hypothesis and can be used in the synthesis of new building materials, including with the use of artificial intelligence.

Development and Characteristics of Infra-Lightweight Foamed Concrete

This research focuses on development of infra-lightweight foamed concrete with very low density. The first step is to manufacture stable preformed foam with optimizing the applied air and water pressure as well as the foaming agent dosage. Then, an appropriate mixing procedure of infra-lightweight concrete is developed. In the experimental plan, 8 different mixes are prepared and tested with different densities, 200, 300, 500, 600 kg/m3. Two values of w/c ratio are used, 0.6 and 0.4. A superplasticizer compatible with the foaming agent is used in the second case (w/c 0.4) in order to achieve the required workability. Compressive strength, thermal conducting and scanning electron microcopy (SEM) measurements have been measured in order to characterize the developed foamed concrete. The experimental results show that for infra-lightweight foamed concrete, the material density is the main parameter governing its compressive strength and thermal conductivity. The SEM observations provide evidences confirming the results of compressive strength and thermal conductivity. The role of w/c is insignificant on compressive strength and thermal conductivity of such type of concrete with very low density. The findings of this investigation revealed that infra-lightweight concrete with self-leveling ability, appropriate strength and different densities can be produce with giving more concern to the performed foam characteristics as well as the mixing technology.

Thermal Properties of Polypropylene Fibrillated Fibre Reinforced Lightweight Foamed Concrete

Thermal Properties of Polypropylene Fibrillated Fibre Reinforced Lightweight Foamed Concrete

Fire resistance and ultrasonic testing of rice husk ash modified foamed concrete

Fire resistance and ultrasonic testing of rice husk ash modified foamed concrete

Utilization of natural zeolite and nano-cuttlefish bone powder as sustainable admixtures in foamed concrete

This study investigates the bleeding and water permeability characteristics in Foamed Concrete (FC) containing natural zeolite as cement substitute and Cuttle-Bone Powder (CBP) as nano-bio-filler. The aim of this study is to conduct a comparative analysis on pore structure modifications and engineering properties between conventional FC and admixture modified FC. First; four distinct FC mixes were obtained by adding CBP as an additive at 0%, 10%, 20% and 30%. Second; three mixes were produced; by replacing cement with calcinated natural zeolite at 5%, 10% and 15% of the mix containing 5%, 10% and 15% CBP; respectively. The foam volume was varied at 10%, 20%, 30% and 40% by volume of concrete in each mix. The test results indicate that substituting cement with natural zeolite in FC containing CBP affects the microstructural properties. In addition, isolated air void formation and reduced foam breakage was observed which restricts the bleeding, drying shrinkage and permeability.

Reuse of sheep wool fibers in the production of ultralightweight foamed concrete: effect of fiber treatment, length, and content on the mechanical properties

Concrete is one of the most widely used materials in the world. Still, its production processes, energy consumption, and high use of raw materials make it one of the most environmentally harmful materials. This study aims to enhance the sustainability of concrete by reducing the amount of binder and incorporating secondary materials into the cementitious matrix. The binder reduction is achieved by using a foaming agent that creates a microporous matrix, significantly decreasing the volume of cement in the material. Additionally, reinforcing the material with sheep wool fiber not only improves its mechanical properties but also gives a new purpose to a commonly discarded secondary material. The research specifically seeks to identify the most effective treatments for sheep wool fiber (including non-treated, salt-treated, lime-treated, NaOH-treated, and surfactant-treated fibers), as well as the optimal fiber length (6, 12, and 20 mm) and content (4.5, 9, and 15 kg/m³) for ultralightweight foamed concrete in terms of mechanical strength. The findings demonstrate excellent compatibility between wool fibers and ultralightweight foamed concrete, with fiber-reinforced samples showing up to a 60% increase in flexural strength and up to a 50% increase in compressive strength. Among the various fiber treatments evaluated, surfactant-treated fibers yielded the best results.

Strength and Thermal Properties of Hollow Foamed Concrete Blocks considering Various Parameters

Hot weather is one of the main problems the residential building construction field faces, especially in the southern hemisphere. Therefore, there is an increasing need to produce materials capable of reducing the high temperature impact. These materials should be characterized by thermal insulation properties without, though, their mechanical properties and load resistance being affected. In this research, cuboid and hexagonal hollow concrete blocks were produced from lightweight foam concrete with different hole shapes and a hole ratio of 30%. An analytical study was conducted for 8 models using the ANSYS v16 program, while the compression behavior and thermal performance of the selected models were studied. Ordinary Portland Cement (OPC), water, sand, and foaming agents were deployed in the production of foamed concrete. In addition to the use of admixtures, materials, such as Superplasticizer (SP), Class F Fly Ash (FA), and Silica Fume (SF), were also utilized. Moreover, the effect of the hole’s shape and the method of bonding were studied. The compressive strength of the concrete blocks, bond shear strength, thermal conductivity, and thermal resistance were tested. It was found that the cuboid shape of the hole block H7 was the most acceptable compared to the other shapes, with a compressive strength of 3.75 MPa, thermal conductivity of 0.149 W/m.k, and a bond shear strength of 0.157 MPa. At the same time, it was found that using bonding adhesive material gave the best results, with the cuboid blocks being compared to using mortar and mechanical bonding.

Experimental Study on Strength and Performance of Foamed Concrete with Glass Powder and Zeolite

Cement manufacturing accounts for approximately 7% of anthropogenic CO₂ emissions. To mitigate environmental impact and achieve “net zero” by 2050, developing cementitious materials that minimize cement consumption is crucial. This research aims to reduce cement usage in Foamed Concrete (FC). The study investigates the mechanical, durability, and thermal properties of FC using two distinct Supplementary Cementitious Admixtures (SCA): Glass Powder (GP) and natural zeolite. Cement was replaced with SCA at varying percentages (0%, 5%, 10%, 15%, 20%, and 25% by weight) in FC. The FC density was adjusted by incorporating foam at 15% and 30% of the total volume of concrete. The study evaluated the flowability of each mix in its fresh state. The mechanical properties were assessed by measuring compressive strength and ultrasonic pulse velocity. The performance of FC was further analyzed in terms of thermal conductivity, sorptivity, and water absorption. The test results revealed that FC with GP combinations exhibited high flowability and an improved strength-to-density ratio. Additionally, water absorption, sorptivity, and thermal conductivity were significantly reduced compared to conventional FC. An extensive cost-benefit analysis highlighted the feasibility of utilizing common waste materials to produce high-grade FC and assessed the impacts of cementitious admixtures as viable alternatives to cement. Doi: 10.28991/CEJ-2024-010-12-06 Full Text: PDF

Preparation and properties of wollastonite-microfiber-modified foamed concrete

Preparation and properties of wollastonite-microfiber-modified foamed concrete

Dynamic properties of alkali residue-based foamed concrete under dry-wet cycles

Alkali residue-based foamed concrete (A-FC) is a lightweight and sustainable building material made from cement, alkali residue, blast furnace slag and foam. The dynamic properties under dry-wet cycles and confining pressure are essential considerations for the engineering application of A-FC. Dynamic triaxial tests were used in this study to explore the influence of dry-wet cycles and confining pressure on the backbone curves, damping ratio, and dynamic elastic modulus of A-FC. A calculation model was established to illustrate the combined effects of confining pressure and dry-wet cycles on the maximum dynamic elastic modulus. Test results indicate that during dry-wet cycles, the coupling effects of temperature, expansion force, and osmotic pressure cause vulnerable pore walls to rupture, pores to become rougher, and microcracks to develop. The backbone curves demonstrate elastoplastic deformation, with no significant change in shape caused by the dry-wet cycles. As the number of dry-wet cycles increases, internal damage accumulates, resulting in a weakening of dynamic deformation ability and a decline in the dynamic elastic modulus. The damping ratio rises with the number of dry-wet cycles once the axial dynamic strain surpasses the transitional strain. Increasing confining pressure can mitigate the adverse impacts of dry-wet cycles on dynamic performance. A-FC demonstrates remarkable durability and favorable dynamic performance, supporting its widespread application in diverse environments.