Effect of Chemical Additives on Carbon Dioxide in the Sustainable Production of Portland Pozzolanic Cement

This research aims to investigate the reduction of CO2 emissions in the cement production process by producing pozzolanic portland cement (PPC) with the characteristics of ordinary portland cement (OPC) using quality-improving chemical additives including calcium nitrate (CN), calcium formate (CF), triethanolamine (TEA) and triisopropanolamine (TIPA). To this end, CN and CF (1, 2 and 3% wt of binder) were added to PPC mortar during the making process, and TEA and TIPA (0.003, 0.006 and 0.01% wt of binder) were added as a solution to the mixture of clinker and natural pozzolan during grinding. The results obtained from compressive strength tests illustrated that, on average, PPC samples containing 15% natural pozzolan led to a 2.7% decrease and a 17.3% increase in the compressive strength respectively compared to OPC with 1% CF and 0.01% TEA. Accordingly, for cement production, clinker can be reduced by 15%, and natural pozzolan be replaced; the reduction in resistance caused by adding natural pozzolan can also be compensated by using chemical additives. Hence, the possibility of replacing 15% of natural pozzolan with clinker, while maintaining the quality of produced cement and reducing the emission of 135 kg of CO2 per ton of cement production is one of the results of this research.