Evaluating deterioration of the properties of lightweight foamed concrete at elevated temperatures

This paper presents the results of an experimental study of varied properties of lightweight foamed concrete (LFC) at high temperatures. The key objective of this experimental study is to investigate the thermal, rheological, physical, and mechanical properties of LFC after being exposed to high temperatures up to 800 °C. To achieve that goal, an extensive study has been carried out to obtain 10 properties, i.e., slump flow, the colour of the surface, mass loss, porosity, thermal conductivity, compressive, split tensile, and flexural strength, modulus of elasticity, and wave velocity tests. In addition, the scanning electron microscopy (SEM) test provides the compositional details of materials. All mixes with varied densities were investigated after exposure to 20, 100, 150, 200, 400, 600, and 800 °C predetermined temperatures. Results also showed that mixes have different behaviours after being exposed to elevated temperatures, yet these behaviours, mass losses in particular, can be generally categorized into three phases based on temperature levels, i.e., 20–200 °C, 200–400 °C, and 400–800 °C. According to the SEM images, it is clear that the pore distributions and void sizes were significantly affected by the density value and the level of high temperature. As the temperature elevated, the void sizes also increased, and in some cases, groups of pores combined to form giant pores. However, by increasing the density, the pores' number, size, and distribution are less influenced by increasing temperature.