Influence of Anhydrite on the Properties and Microstructure of Aluminophosphate Cement

Abstract

Aluminophosphate cement (APC) is a new type of hydraulic cementitious material with many potential functions. Microscopic analysis techniques were used to study the effect of anhydrite on the performance and hydration process of APC under standard curing conditions. The results show that adding an appropriate amount of anhydrite promotes the hydration of APC. The highest compressive strength is reached at an anhydrite content of 15 wt.%. As the anhydrite content increases, the APC’s compressive strength decreases. The microscopic analysis of the hydration product morphology shows that the incorporation of anhydrite produces ettringite and other hydration products, improving the microstructure of the cement paste. The mercury intrusion porosimetry results show that the total porosity of the hardened APC paste decreases, and the microstructure becomes denser with an increase in the curing age, resulting in an increase in the compressive strength over time.

Analysis of Pore Structure in Cement Pastes with Micronized Natural Zeolite

“…Recent studies have made it evident that the permeability and strength of cement pastes are governed by pore size distribution rather than porosity [ 23 ]. The smaller the pore size, the higher the compressive strength and the lower the thermal conductivity [ 24 ]. One of the most widely used methods for assessing the pore size distribution is mercury intrusion porosimetry (MIP).…”