Design and Fabrication of Concrete Mixtures Using Metakaolin Calcined at Different Temperatures

Abstract

The present research is aimed at exploring formulations of concrete mixes that incorporate metakaolin (MK), derived from kaolin calcined at different temperatures (700°C and 800°C). The metakaolin was generated in a laboratory setting from pure kaolin extracted in the Magistral de Copala development area, Concordia, Sinaloa. The experimental design encompasses five variants of concrete mixes, including a reference standard and options with 15% and 20% cement replacement with metakaolin at 700°C, as well as mixes with the same substitution percentage using metakaolin at 800°C. The collected results indicate that fluctuations in the calcination temperature do not exert a substantial impact on the mechanical and deterioration resistance characteristics of concrete, as both temperatures promote the formation of metakaolins with high pozzolanic activity. The formulation highlighted for its superior performance in terms of mechanical strength (compression) and durability (microstructural parameters, electrical resistivity, chloride migration) is the one using MK calcined at 800°C, replacing 15% of the weight of the cement. These findings underscore the possibility of obtaining environmentally friendly mineral additions by substituting significant amounts of cement, thus contributing to reducing the carbon footprint associated with its manufacturing.