An Experimental Study on the Effect of Foamed Concrete Bulk Density on its Thermal and Mechanical Properties

Abstract

Foamed concrete is considered a lightweight thermal insulation material due to its air-filled cellular structure, which helps reduce dead loads on structures and save energy. It is produced by introducing a foaming agent that generates air bubbles into the cementitious mortar. The entrained air bubbles reduce the bulk density of the mortar, resulting in lightweight and thermally insulating foamed concrete. This research aims to investigate the relationship between the bulk density of foamed concrete and its thermal properties—specifically thermal conductivity and thermal resistance—as well as its mechanical properties, with a focus on compressive strength. Additionally, the study seeks to establish mathematical correlations between these parameters. An experimental study was conducted on lightweight foamed concrete samples with dry bulk densities below 800 kg/m³. Ten foamed concrete mixtures were prepared using a synthetic foam generator with a fixed cement content of 350 kg/m³. The mix proportions were adjusted to achieve varying bulk densities by altering the water-to-cement ratio (W/C), foaming agent-to-cement ratio (F/C), and sand-to-cement ratio (S/C). Various tests were performed to determine the physical, thermal, and mechanical properties of the foamed concrete, including dry bulk density, thermal conductivity coefficient, thermal resistance, and compressive strength. At the end of this research, the relationships between dry bulk density, thermal conductivity and compressive strength of foamed concrete were established.