Synergistic Antibacterial Effects of Saponified Waste Oil and Cetrimonium Chloride (Ctac) in Cement Pastes

Microbial colonization activity in cement pastes can lead to biodeterioration, compromising the structural integrity over time. This study investigates the antibacterial performance of cement pastes modified with saponified cooking oil (SCO) and cetrimonium chloride (CTAC). Different doses of CTAC and SCO were blended with cement paste on four bacterial strains: Escherichia coli and Pseudomonas aeruginosa (Gram-negative), Bacillus subtilis, and Staphylococcus aureus (Gram-positive). The results showed that B. subtilis revealed the highest sensitivity to CTAC's antibacterial activity, especially at high doses (up to 1%). This effect was enhanced by adding SCO, indicating a clear synergistic interaction. Gram-positive bacteria generally reacted more strongly to the modified cement paste comparing with Gram-negative bacteria. The results demonstrated the potential of CTAC/SCO-modified cement for use in microbial-sensitive environments such as hospitals, and food processing facilities.