Investigating the Effects of Polyaluminum Chloride on the Properties of Ordinary Portland Cement

This study investigates the mechanical and microstructural properties of paste comprising ordinary Portland cement (OPC) added with polyaluminum chloride (PACl). The properties of the resulting mixture are analyzed using compressive strength, X-ray diffraction, scanning electron microscopy (SEM), mercury intrusion porosimetry, and thermogravimetric analysis. The results show that the addition of PACl improves the mechanical properties of OPC paste, that calcium-(aluminum)-silicate-hydrate (C-(A)-S-H) gel and Friedel’s salt are the major products forming from the reaction with the aluminum and chloride ions in PACl, and that the portlandite content decreases. Moreover, the size and number of micropores decrease, and compressive strength increases. All these phenomena are amplified by increasing PACl content. SEM images confirm these findings by revealing Friedel’s salt in the micropores. Thus, this work confirms that adding PACl to OPC results in a mixture with superior mechanical and microstructural properties.