Workability and Mechanical Properties of Structural Foamed Concretes with Different Dry Densities, and Fine Sand Grain Sizes: Preliminary Study

With the global construction industry in full swing and the desperate quest to reduce energy consumption and greenhouse gas emissions, there is a growing demand for new technologies to manufacture lightweight concrete structures. This work focuses on foam concrete (FC) and presents the initial results of current experimental campaigns. The purpose of this paper is to investigate the relationship between the flow, mechanical strength, and elastic modulus of the samples and the different dry densities, and the fine aggregate sizes. All samples were cured in water to maintain a constant temperature and humidity environment. The target density of the specimens ranged from 1350 to 1600 kg/m3 with two grades of fine aggregate size. The findings indicate that while the increase in dry density reduces the flow of the foamed concrete specimens, the increase in fine aggregate diameter greatly improves the flowability of the foamed concrete when compared to the control group. Furthermore, the mechanical strength of foamed concrete was enhanced by smaller fine sand gradation because of the presence of more refined pore structure and improved bubble stability. In particular, the foamed concrete specimen with finer sand particle size had a maximum compressive strength value of around 45 MPa and an elastic modulus of about 18 GPa at a dry density of about 1600 kg/m3.