Experimental Study for Structural Behaviour of Precast Lightweight Panel (PLP) Under Flexural Load
Precast lightweight concrete slab is first fabricated in workshop or industrial before construction and then transported to site and installed by skilled labour. It can reduce construction time by minimizing user delay and time for cast-in-situ to increase workability and efficiency. is environmental friendly and helps in resource reduction. Although the foamed concrete has low compressive strength compared to normal weight concrete but it has excellent thermal insulation and sound absorption. It is environmental friendly and helps in resource reduction. To determine the material properties of foamed concrete, nine cubes and six cylindrical specimens were fabricated and the results were recorded. In this study, structural behaviour of precast lightweight panel (PLP) with dry density of 1800 kg/m3 was tested under flexural load. The results were recorded and analysed in terms of ultimate load, crack pattern, load-deflection profiles and strain distribution. Linear Voltage Displacement Transducers (LVDT) and strain gauges were used to determine the deflection and strain distribution of PLP. The theoretical and experimental ultimate load of PLP was analysed and recorded to be 70 and 62 kN respectively, having a difference of 12.9%. Based on the results, it can be observed that PLP can resist the adequate loading. Thus, it can be used in precast industry for construction purposes.
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/m 3 , 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/m 3 density. The addition of PP fibres also indicated that it could reduce the surface temperature of higher-density foamed concrete compared to lower densities.
Manufacture, testing and numerical analysis of an innovative polymer composite/concrete structural unit
A study of a novel advanced composite/concrete duplex beam is presented, including a four-point-load experimental beam-bending test and a numerical finite-element (FE) analysis. The manufacturing process for the beam, which uses Advanced Composites Group Ltd's optimized low-temperature-cure vacuum process prepreg technology with preimpregnated carbon and glass fibre composites, is outlined. The basic components of this beam consist of a concrete section in the compressive region, a glass-fibre-reinforced polymer (GFRP) composite sandwich foam core web section and a GFRP flange interleaved with high-strength unidirectional carbon fibre tape. The beam was designed such that the neutral axis was situated at the soffit of the concrete to prevent tensile forces developing in the concrete. In an attempt to achieve composite action between the concrete and GFRP composite, indents were placed in the vertical faces of the shuttering. During the loading test certain areas of the shuttering separated from the concrete prematurely; however, the indents did provide continued partial composite action to failure. The failure of the beam occurred by flexural crushing of the concrete followed by failure of the webs in shear. Prior to the separation of the shuttering and concrete the behaviour of the beam was as predicted by the FE analysis. The composite/concrete beam had half the flexural rigidity, a similar ultimate bending-load capacity and a weight reduction of approximately 75% compared to a singly reinforced concrete beam of the same dimensions with a 2% area of reinforcement. The low flexural rigidity can be increased by the use of higher-strength concrete, thus enhancing the modulus of elasticity of the concrete and the flexural rigidity of the whole beam.