Investigation on structural behaviour of concrete sandwich beams with light weight composite and shear connectors

Abstract

Due to rapid exhaustion of the natural resources required for building materials, there is a need in developing sustainable alternative materials. In recent years, research in the field of precast technology and lightweight structural members has been in progress. Composite Sandwich system generally consists of insulated core sandwiched between concrete wythes. The main objective of this project is to study the experimental and analytical response of Composite Sandwich Beam(CSB) under four-point flexural testing. Normally, the neutral axis of the beam has zero bending stress and shear force predominantly acts on the neutral axis. In order to reduce the usage of concrete materials and the self-weight of the beam, Expanded Polystyrene which tends to be light weight and insulated core is placed in the neutral axis portion. In order to make it much more sustainable, cement is also partially replaced by 10 % of its weight with fly ash. Truss shaped shear connectors are used which will increase the shear and ductile nature of CSB. In the analytical study, both conventional RCC and CSB are analysed and compared by using Finite Element Analysis (Ansys-APDL). Four-point flexural loading is applied on the beam specimens to assess its flexural strength experimentally. The effect of thickness of core, load–deflection curve and strain behaviour are discussed. The test results indicate that by the usage of Expanded Polystyrene as an interlayer, there is an 8.75% decrease in the total weight thereby reducing the material utilization. This leads to the development of composite material for structural beam applications without compromising its strength and it can be used in low-cost housing and green building.