Life cycle assessment to produce LC³ cements with kaolinitic waste from the Amazon region, Brazil

Abstract

The present study was developed with the aim of determining the environmental impact of the production process (cradle-to-gate) of Limestone Calcined Clay Cements (LC³) produced with kaolinitic residues from the Brazilian Amazon, through a life cycle assessment (LCA). For this purpose, 6 LC³ mixtures were prepared from combinations of clinker, gypsum, and metakaolin: limestone filler in the ratios 2:1, 1.5:1 and 1:1, replacing 45% and 60% Ordinary Portland Cement (OPC). The LC³ cements were compared with two cements already produced industrially. CO2 emissions associated with the transportation of raw materials to produce LC³ cements increased significantly, especially for the cements where 60% clinker was substituted, with CO2 emissions up to 2–3 times higher than for the reference cements. Despite that, LC³ cements showed a reduction in energy demand of up to 28% and total CO2 emissions of up to 38% compared to commercial cements. In this way, the conducted study demonstrates the high environmental potential of LC³ cements with kaolinitic residues from the Amazon region for reducing pollutant emissions in the manufacture of cement.