Durability Performance of Blended Cement with Calcined Illitic Shale

CORDOBA, GISELA P.; ROSETTI AGUSTIN; ZITO SILVINA; RAHHAL VIVIANA FATIMA; FALCONE DARIO; IRASSAR EDGARDO FABIAN

ACI MATERIALS JOURNAL

AMER CONCRETE INST

Año: 2022 vol. 119

0889-325X

The use of calcined clays in cement (kaolinitic and common calcined clays) introduces challenges due to the high alumina content, large specific surface area, and high-alkali content. This paper examines the performance against sulfate attacks, alkali-silica reactions, and chloride penetration in mixtures with calcined illitic shale (CIS). Replacement of high and moderate alkali content cement with 25%CIS significantly reduces the expansion in the alkali-silica reaction (ASR) test, as the pozzolanic reaction contributes to the combination of alkalis. Replacing 20% white portland cement with CIS allows the formulation of sulfate-resistant cement by limiting the formation of gypsum and ettringite. The incorporation of 25% CIS in concrete does not significantly increase chloride ingress. Therefore, blended cements with replacement levels of 20 to 25% of portland cement by CIS reduce or maintain the performance against ASR, sulfate attack, and chloride penetration.