Research on the properties of wet-ground waste limestone powder as foam stabilizer in foamed concrete

Abstract

Two unavoidable problems of lightweight foamed concrete: low strength and low stability. The low stability of the foams was the main reason. Recently, the particle-stabilized foams (PSF) have been proposed because of its high stability. However, most PSF had to use nanoparticles, such as nano-silica, carbon nanotubes, which will lead to high foam density and cost. In this study, waste limestone powder (WLP) was processed by the wet grinding process (i.e., WGWLP, D50 = 281 nm), and WGWLP was used as foams stabilizer to prepare high stability foams for the preparation of high-stability and high-strength foamed concrete. The foaming agent and foams properties was investigated, and the mechanism of foams stabilization was revealed by foams microstructure, SEM and EDS; the properties of WGWLP or WLP stabilized foams in foamed concrete was revealed by compressive strength, Micro-CT and foamed concrete stability and homogeneity. Results showed that the adsorption of WGWLP on the liquid film increased the liquid flow resistance and limited the discharge of the liquid, thereby improving foams stability. In addition, WGWLP absorbed a large amount of free energy of the liquid film and limited the decreased of surface tension, thereby leading to the homogeneity and high strength of foamed concrete. Such results suggested that WGWLP was expected to as a foams stabilizer, and the foamed concrete with the WGWLP stabilized foams showed a considerable performance.