Experimental Study on Thermal Properties of Structural Lightweight Aggregate Concrete

Abstract

This paper investigates the thermal properties of structural lightweight aggregate concrete. Different types of concretes with four types of lightweight aggregates and several water/cement ratios were prepared. The strength classes of the produced lightweight aggregate concretes ranged from LC 16/18 a LC60/66, whereas the density classes ranged from D1.6 to D2.0. A normal weight aggregate was also used as reference. The impact of the concrete constituents on thermal conductivity, thermal diffusivity and specific heat was assessed by a modified transient test method and relations between those thermal properties and both density and water content of concrete were established. A significant exponential correlation between thermal conductivity and density of concrete was achieved. On average, thermal conductivity decreased about 0.6% per each 1% increment in aggregate porosity, 8.3% per each 50 L/m3 increment in coarse aggregate volume and 3-9% per each reduction of 1% by weight in water content. The specific heat decreased with density of concrete, whereas both thermal diffusivity and thermal inertia increased. Furthermore, it was found that the thermal conductivity of structural lightweight aggregate concrete can be half of that of normal weight concrete of similar composition, which can contribute to more energy efficient buildings.