Thermal and Structural Behaviour of Sandwiched Reinforced Cement Concrete Wall Panels

Abstract

The energy efficiency of a building predominantly depends on the temperature gradient across the wall. The use of Sandwiched Concrete Panels (SCP) to achieve energy efficiency inside buildings is gaining importance all over the world. This study focuses on comparing the temperature gradient across sandwich concrete wall panels made of two different insulation materials viz. Extruded Polystyrene (XPS) and Expanded Polystyrene (EPS) with two different sizes of steel (8 mm and 10 mm dia.) used as reinforcement and shear connectors. Two different concrete grades viz. M25 and M40 were studied. The thickness of concrete wythes on both sides of the SCP and the inner insulation material (XPS and EPS) were varied to understand their effect on thermal insulation. The external surface of the samples was subjected to an elevated temperature of 75 °C for 24 hours continuously and the temperature measurements across the SCP were recorded. This was done by simulating the real-time temperature effect using an indigenously developed oven, designed and fabricated to fit the SCP sample size which comprises an electronic thermostat and temperature sensor unit arrangement. Additionally, a one-dimensional finite element analysis was carried out to predict the theoretical interface temperature and inner surface temperature of the SCP samples with necessary assumptions. Both the experimental and FEA temperature values corroborated well. Further, all the samples were subjected to compression and flexural testing to evaluate their structural properties. Influence of type of insulation material used viz. XPS and EPS, size of steel reinforcement used viz. 8 mm and 10 mm dia. were found to be not that significant in terms of both thermal and structural behavior.