Structural behaviour of precast lightweight foamed concrete sandwich panel (PLFP) with shear truss connectors

Precast system is playing a very important role in industrialize building system to construct more affordable and quality houses to meet the high demands. Many researches have been carried out to develop precast sandwich wall panel with more benefits such as lighter in weight, environmental friendly and easy to construct compared to normal reinforced concrete panel. Therefore, a study was carried out to develop Precast Lightweight Foamed Concrete Sandwich Panel (PLFP) with shear truss connectors. The objectives of this study are to numerically investigate the PLFP panel with single and double shear truss connectors to determine its structural behaviour with validation from experimental work and to develop the empirical equation to predict its ultimate strength under axial load. PLFP panel is made of foamed concrete as the outer wythes which enclose a core layer of polystyrene. The wythes were reinforced with steel bars and tied to each other through the polystyrene layer by using steel shear connectors (bent at an angle of 45°). Experimental testing had been conducted to determine the material properties of foamed concrete and steel bar and used for PLFP model in finite element analysis. Eight half scaled PLFP panels were tested experimentally under axial load until it failed. Ultimate load carrying capacity, load lateral deflection profile, strain distributions and failure mode were recorded. Finite element analysis was carried out on PLFP panels which were validated with experimental results. Full scaled PLFP panels with single and double shear truss connectors had been studied numerically to investigate the effects of geometrical imperfection, slenderness ratio, thickness, and shear connectors toward its structural behaviour. From the results, it was found that when the rate of geometrical imperfection and slenderness ratio of PLFP panel increased, the ultimate load of PLFP panel decreased. The use of double shear truss connectors indicated improvement in the PFLP’s strength and stability under axial load and longitudinal shear force compared to single shear truss connectors. An empirical equation which was modified from previous research is proposed to predict the ultimate load carrying capacity of PLFP under axial load

Structural behaviour of beam with HDPE plastic balls subjected to flexure load

This paper presents the structural behavior of reinforced concrete beam embedded with high density polyethylene balls (HDPE) subjected to flexural load. The HDPE balls with 180 mm diameter were embedded to create the spherical voids in the beam which lead to reduction in its self-weight. Two beam specimens with HDPE balls (RC-HDPE) and one solid beam (RC-S) with dimension 250 mm x 300 mm x 1100 mm were cast and tested until failure. The results are analysed in the context of its ultimate load, load-deflection profile, and crack pattern and failure mode. It was found that the ultimate load of RC-HDPE was reduced by 32% compared to RC-S beam while the maximum deflection at its mid span was increased by 4%. However, RC-HDPE is noticed to be more ductile compared to RC-S beam. Both types of beams experienced flexure cracks and diagonal tension cracks before failur

Thermo‑mechanical properties of various densities of foamed concrete incorporating polypropylene fibres

Concrete has been extensively used in the development of urban infrastructure works. However, it has the tendency to absorb solar radiations, and these radiations are released back into the air in the form of heat energy. Dense concentration of infrastructures releases more heat, causing urban heat island (UHI) effect in which the ambient temperature of the urban areas rises slightly than the surrounding areas. Tropical countries which have a hot climate throughout the year are more affected by the UHI effect. Therefore, thermal insulating materials need to be introduced in the field of concrete construction. Foamed concrete, which has air voids in its matrix, is a potential thermal insulating material. But due to reduced density, it, however, achieves lower strength. Polypropylene (PP) fibres are used to reinforce the foamed concrete and improve its compressive and tensile strengths. In this study, three different densities, 1400, 1600 and 1800 kg/m3, were cast, and 0.8% PP fibres were added. The thermo-mechanical properties were investigated in terms of thermal conductivity, surface temperature, compressive and tensile strengths with and without the addition of PP fibres. Based on the findings, the addition of PP fibres gained more strength and reduced thermal conductivity in the lower densities of foamed concrete. In contrast, it had an opposite impact on 1800 kg/m3 density. The addition of PP fibres also indicated that it could reduce the surface temperature of higher-density foamed concrete compared to lower densities

Chemical and fresh state properties of foamed concrete incorporating palm oil fuel ash and eggshell ash as cement replacement

Malaysia faces three major environmental problems, out of which solid waste and management is one of them. Palm Oil Fuel Ash (POFA) and eggshells are two agro-food waste materials which are produced in enormous quantities in Malaysia. Due to the characteristics possessed by eggshells and POFA, these waste materials can potentially be utilized in the production as cement replacement, reducing the use of cement which is one of the major production of Carbon Dioxide (CO2) gas emissions. This study was conducted to determine the chemical and fresh state properties of foamed concrete incorporating POFA and eggshell ash (ESA) as cement replacement. Based upon the results, it was observed that the increase in usage amount of POFA and ESA as cement replacement, the workability of foamed concrete reduced without blocking. For the chemical analysis result shows the POFA which had high amount of silicon dioxide and ESA having large amount of calcium oxide were compatible and could be used together as cement replacement. The use of ESA and POFA as cement replacement to reduce the cement consumption with various percentage of ESA (0% - 15%) and POFA (20% - 35%) in 1800 kg/m3 density of foamed concret

Utilization of palm oil fuel ash and eggshell powder as partial cement replacement - a review

The increase in population leads to increase in construction of houses and other buildings to accommodate these people. The extensive use of concrete for constructional purposes leads to release of Carbon Dioxide (CO2) gas into the atmosphere which adds to the already increased global warming. The increase in urbanization has also lead to increased generation of waste materials. These waste materials are by-products, which are disposed in landfills causing environmental and health issues. The utilization of agricultural wastes as cement substitute is a great alternative for reducing the use and production of cement, which contributes to 5% to 7% of global CO2 emissions alone. Palm Oil Fuel Ash (POFA) Eggshells are two major agricultural wastes, which are generated in abundance in Malaysia. This paper reviews the combined utilization of Eggshells Powder (ESP) and POFA as potential partial cement replacement material and development of bio-concrete, which may help in reducing the environmental issues that are caused by the agricultural by-products. They have been used successfully but individually in concrete. The pozzolanic activity triggered by POFA requires Calcium Hydroxide which cement provides to a limit. Eggshells when grinded into Eggshells Powder (ESP) are rich in calcium oxide and can provide the required calcium hydride and enhance the pozzolanic reactio

Incorporation of Palm Oil Fuel Ash and Egg shell Powder as Supplementary Cementitious Materials in Sustainable Foamed Concrete

The release of carbon dioxide (CO2) during the production of cement and the increase in waste generation has allowed the construction to focus on sustainability by replacing cement with agricultural waste resources such as Palm Oil Fuel Ash (POFA) and Eggshell Powder (ESP). This experimental study focuses on developing sustainable foamed concrete incorporating high content of POFA and ESP as cement replacement with the aim of cement conversion, reduction in natural resources depletion, reduction of CO2 emissions and cleaner production. Cement was replaced using 30 and 35% POFA and 5 to 15% ESP by weight of cement. It was observed that the flowability decreased with the increase in the content of POFA and ESP; this is due to their ability to absorb water. It was also observed that 40% cement replacement achieved satisfactory compressive strength while the tensile stress loss was significant. This study confirmed that recycling and reusing of POFA and ESP are possible in foamed concrete which could be used for non-structural applications

Preliminary Investigation of Thermal Behavior of Lightweight Foamed Concrete Incorporating Palm Oil Fuel Ash and Eggshell Powder

This study was performed to investigate the thermal and mechanical properties of foamed concrete when supplementary cementitious materials (SCMs) are utilized. Sustainable foamed concrete of 1800 kg/m3 dry density was prepared by incorporating Palm Oil Fuel Ash (POFA) ranging from 30 % to 35 % and Eggshell Powder (ESP) from 5 % to 15 % as SCMs. It was found that the combined utilization of POFA and ESP in the foamed concrete produced favorable results by reducing the thermal conductivity up to 42.68 % compared to the control sample, thus enhanced thermal insulating property of foamed concrete. This study confirmed that recycling and reusing of POFA and ESP are possible in foamed concrete which could be used for non-structural applications where thermal insulating is required

Green and Sustainable Concrete – The Potential Utilization of Rice Husk Ash and Egg Shells

Concrete which is widely used material in the construction industry, has a carbon footprint. Approximately 10% of global Carbon Dioxide (CO2) gas is emitted during the production of cement which is vital ingredient of concrete. The increase in production of cement affects global warming and climate change. Therefore, many have attempts have been made to develop green and sustainable concrete by utilizing different waste materials. With the utilization of waste materials as cement replacement, the CO2 gas emissions can be reduced as well as resolve the environmental issues that the inhabitants face during the disposal of such waste materials. This paper reviews the potential and innovative utilization of Rice Husk Ash (RHA) and Eggshells as partial cement replacement to develop green concrete. RHA which is rich in silica and eggshells contain identical amount of calcium oxide as cement, when finely grinded and used together as partial cement replacement, can trigger a pozzolanic reaction, in which silica reacts with calcium oxide resulting in the formation of calcium silicates which are responsible for achieving higher strengths

Overview of empirical equation prediction for ultimate axial load of precast lightweight foamed concrete sandwich panel (PLFP)

In the absence of analytical theory, empirical equation is useful in estimating the ultimate load carrying capacity of structural component. Empirical approach means the collection of data on which to base a theory or derive a conclusion in science. It is part of the scientific method. The empirical method is often contrasts with the precision of the experimental method where data are derived from an experiment. This paper review the development of empirical equation from solid reforced panel to sandwich panel. The previous developed empirical equations are be able to predict an adequate ultimate strength of PLFP panel under axial loading due to the safety factor reduction. Series of experiment and Finite Element ANALYSIS (FEA) were carried out to produce sufficient data to analyze the previous developed empirical equation to predict the ultimate load carrying capacity. From findings, a new empirical equation is in need to predict the ultimate axial load of sandwich panel in order to get accurate predictio

Evaluation of combined utilization of marble dust powder and fly ash on the properties and sustainability of high‑strength concrete

With the recent increase in demand for high-strength concrete, higher cement content is utilized, which has increased the need for cement. The cement industry is one of the most energy-consuming sectors globally, contributing to 10% of global carbon dioxide (CO2) gas emissions and global warming. Similarly, with rapid urbanization and industrialization, a vast number of by-products and waste materials are being generated in abundance, which causes environmental and health issues. Focusing on these two issues, this study aimed to develop an M50-grade eco-friendly high-strength concrete incorporating waste materials like marble dust powder (MDP) and fy ash (FA) as partial cement replacement. 2.5%, 5%, 7.5%, and 10% MDP and FA by weight of total binder was utilized combinedly, such that the 5%, 10%, 15%, and 20% cement content was replaced, respectively. The fresh state properties in terms of workability and hardened state properties in terms of compres�sive and fexural strengths were evaluated at 7, 14, 28, 56, and 90 days. Furthermore, to assess the environmental impact of MDP and FA, the embodied carbon and eco-strength efciency were calculated. Based upon the results, it was observed that a combined 10% (5% MDP and 5% FA) achieved the highest strength; however, 15% (7.5% MDP and 7.5% FA) substitution could be optimal. Furthermore, the combined utilization of FA and MDP also enabled a reduction in the total embodied carbon. It decreased the cost of concrete, resulting in an eco-friendly, high-strength concrete