Environmental Assessment of Limestone Calcined Clay Cement in Australia

Abstract

The Australian government aims to achieve net-zero carbon emissions by 2050. Therefore, introducing a market-oriented carbon emissions trading scheme to offer a financial reward (or penalty) to those who emit below (or beyond) the allowed limits is expected. Under such a scheme, the cement industry is forced to reduce its energy consumption and carbon emissions. Limestone calcined clay (LC3) cement has been extensively studied and regarded as a promising solution to substitute ordinary cement clinker up to 50% without compromising the performance of concrete. In this paper, a comparative life cycle assessment (LCA) of the LC3 mortar considering cradle-to-gate system boundaries is conducted for the scenario in Australia. The LCA is undertaken on 122 collected LC3 mortar mix designs, and it includes the modification of traditional cement production to incorporate the calcined clay manufacture and evaluation of the environmental impact of different substitution levels. Results show that CO2 emissions associated with LC3 system production were reduced by up to 38% compared to Ordinary Portland cement mixtures.