Influence of fibers and bubble structure on thermal conductivity and mechanical performances of foam concrete

Abstract

This study aims to effects of fibers and bubble structure on thermal conductivity and mechanical performances of foam concrete. The factors of fiber type, length, fiber dosage, and silica fume dosage were considered. The workability and compressive strength tests were carried out. The bubble structure was observed. Numerical simulation of thermal conductivity was performed. The results indicated that the influence of a single factor on the strength of foam concrete is slight. The addition of silica fume significantly reduces the workability of foam concrete. The synergistic effect of silica fume and PP fiber can improve the compressive strength of foam concrete. The compressive strength of foam concrete with good performance is 7.2 MPa, and the dry density is 827 kg/m3. The pore diameter of about 400 μm is the main pore diameter that affects the strength of foam concrete. The thermal conductivity of foam concrete with the same porosity but different pore size distribution is similar when the pores are closed. The defects on the hole wall, small aperture and uniform distribution are still conducive to improving the strength. When the profile of the same temperature passes through the pore, the curve is concave and convex first, and the larger the pore size, the more obvious this phenomenon is. The holes in the foam concrete play a role in dissipating energy during heat transfer.