Aluminum hydroxide (AH3) has recently been shown to be able to activate hydration in ternesite, a phase found in some calcium sulfoaluminate (CSA) cements. This study explored the capacity of a number of calcium aluminates (C3A, C12A7, CA and C4A3) to activate ternesite hydraulic reactivity. After laboratory synthesis, the aluminates were blended with ternesite at a ratio of 1:2 and their hydration was monitored with isothermal conduction calorimetry for 7 days at 25 °C. The resulting pastes were analysed with XRD, FTIR and DTA. The presence of ternesite in the pastes altered the aluminate heat flow curves, shortening the induction period and bringing the reaction peak forward, an indication of hastened hydration. Ternesite also altered the reaction products, which included calcium monosulfoaluminate hydrate and strätlingite.

This paper has been funded from BIA2016-76466-R project as well as the Regional Government of Madrid Community and European Social Fund (Geomaterials Programme2 S2013/MIT-2914). Authors thank to Ministerio de Economía y Competitividad the young researcher contract given to Myriam Montes. Financial support for Dr. Paula M. Carmona-Quiroga's participation was provided by the Spanish Ministry of the Economy and Competitiveness under project BIA2015-73237-JIN.

Peer reviewed