Factors Influencing the Pore Structure Parameters of Lightweight Cement-Based Foams

This study quantifies the pore wall spacing and shape factor of lightweight cement-based foam pore structure and investigates its correlation with density, pozzolan, compressive strength, and thermal conductivity. The lightweight cement-based foam mixtures were prepared for the densities of 800-400 kg/m(3) and by replacing cement with fly ash, silica fume, and metakaolin up to 20 % by mass. The nondestructive technique of X-ray microtomography was used for quantifying the pore structure parameters. In addition, the transient plane heat source technique was used to evaluate the thermal conductivity of these mixtures. The results show that the optimal pore wall spacing increases from 0.28 to 0.55 mm as the density rises from 400 to 800 kg/m(3). It was observed that the median pore wall spacing (SP50) values increases as the cast density get higher. While the reduction in thermal conductivity was noticed for lower SP50 values. Furthermore, incorporating pozzolanic admixtures at higher cement replacement ratios affects the pore wall spacing. Moreover, spherically shaped pores were found in all mixtures.