Performance evaluation of foaming agents in cellular concrete based on foamed alkali-activated slag

Abstract

In this work, three different foaming agents were selected and their performance on density, compressive strength, pore structure, and molecular structure of alkali-activated blast furnace slag cellular concrete have been investigated. For this purpose, pre-formed foams based on sodium lauryl sulfate, protein-based foaming agent, and hydrogen peroxide were added to the alkali-activated slag paste with determined activator composition. After curing, density and compressive strength of cellular concretes were evaluated. Also, macroscopic pore size distribution was investigated by image processing technique for studying its relation with density and compressive strength. Results showed that with increasing the amount of foam, the density and the compressive strength decreased due to increases in both the number of pores per area and the pore average size. Samples containing protein-based foam showed higher mechanical strength, which could be due to its effect on the molecular structure of hydration product resulting in a stronger bond and hence higher compressive strength.