Rheology and Porosity of Ultralow Density Foamed Cement Pastes Derived from Ordinary Portland Cement and Hydrogen Peroxide

Abstract

Foamed cement-based materials possess outstanding flame resistance, fire thermal, and sound insulation, but it is difficult to obtain the desired porosity and pore size due to the complicated equilibrium relations between the fresh paste rheology and hardened porous matrix. In this article, we develop ultralow density porous Portland cement pastes to evaluate the rheological properties and foaming process. The results show that air permeability and temperature are essential parameters for altering the pore size of foamed cement pastes. Furthermore, the equilibrium relationships between the pore radius and the rheological parameters of cement pastes are established. Moreover, the mix ratio design of foamed cement pastes is also promoted. Accordingly, this work sheds light on the formation mechanism of the porous structure for ordinary Portland cement pastes, as well as presents a new strategy towards fabricating other inorganic materials with desired porosity and mechanical property.