Gas production and slurry expansion behavior of hydrogen peroxide foamed cement pastes

Abstract

This study investigated the foaming behavior of hydrogen peroxide (H₂O₂) foamed cement pastes, with a particular focus on gas production and slurry expansion processes. The effects of varying manganese dioxide (MnO₂) dosage (0 %–2 %) and H₂O₂ dosage (3 %–9 %) on the foaming process of fresh slurry and the properties of hardened specimens were examined. The findings revealed that gas production from H₂O₂ decomposition followed pseudo-first-order kinetics, with a portion of the generated gas volume converting into slurry volume at lower reaction speeds. While higher H₂O₂ dosages more effectively improved the final gas and slurry volume, increased MnO₂ dosages were more effective in accelerating the foaming process and thereby improving H₂O₂ and gas utilization efficiency. Furthermore, higher MnO₂ dosages raised the first-order reaction rate constants of the gas production curves, whereas higher H₂O₂ dosages had the opposite effect. Additionally, increased MnO₂ or H₂O₂ dosages led to larger pore sizes and a reduction in dry density, compressive strength, and thermal conductivity. These findings underscore the significance of characterizing the foaming process and offer insights into the foaming mechanisms of cement pastes.