Title: Effect of Different Metakaolins on Chloride-Related Durability of Concrete

Author(s): Oswaldo Cascudo, Rodrigo Teodoro, Andrielli M. de Oliveira, and Helena Carasek

Publication: Materials Journal

Volume: 118

Issue: 3

Appears on pages(s): 3-14

Keywords: amorphous content; chloride migration; durability; electrical resistivity; metakaolin; microstructure; performance; porosity

DOI: 10.14359/51732634

Date: 5/1/2021

Abstract:
The main purpose of this work is to evaluate which parameters obtained from the characterization of metakaolins (MKs) (physical, chemical, and mineralogical parameters) have greater relevance in terms of positive impact on concrete durability properties related to chlorides, and which scientific arguments support these results. In parallel, a comparative study between three different MKs was carried out to statistically evaluate the ability that each of these materials must modify and eventually improve concrete durability properties associated with chlorides (electrical resistivity and chloride migration). A discussion of the results was carried out considering evaluations of the microstructure, emphasizing the cementitious systems’ porosity (by mercury intrusion porosimetry [MIP]). It was found that MKs contributed to reduced porosity and refined pores, which made the transport of chlorides significantly more complex, and that some characteristics of MK, especially its amorphous content, have been more decisive for that.