An Experimental Investigation of Mechanical Properties of Lightweight Foamed Concrete Subjected to Elevated Temperatures up to 600°C

Abstract

Although Lightweight Foamed Concrete (LFC) has low mechanical properties compared to normal weight concrete, there is a possibility of using this material as partition or load-bearing wall in low-rise residential construction. Before it can be considered for use as a load-bearing element in the building industry, it is essential to obtain reliable information of its mechanical properties at ambient and elevated temperatures for quantification of its fire resistance performance. This paper will reports the results of experimental works that have been performed to examine and characterize the mechanical properties of LFC subjected to elevated temperatures. LFC with 650 and 1000 kg/m³ density were cast and tested under compression and three point bending. The tests were carried out at ambient temperature, 100, 200, 300, 400, 500, and 600°C. The experimental results of this study consistently demonstrated that the loss in stiffness for cement based material like LFC at elevated temperatures occurs predominantly after about 90°C, regardless of density. This indicates that the primary mechanism causing stiffness degradation is microcracking, which occurs as water expands and evaporates from the porous body. As expected, reducing the density of LFC reduces its strength and stiffness. However, for LFC of different densities, the normalised strength and stiffness (ratio of elevated temperature value to ambient temperature value) – temperature relationships are very similar.