Comparison between curing conditions of zeolite and siltstone cement pastes at low W/B ratio after 91 days

Published in: Engineering Innovations for Global Sustainability: Proceedings of the 14th Latin American and Caribbean Conference for Engineering and Technology
Date of Conference: July 20-22, 2016
Location of Conference: San Jose, Costa Rica
Authors: Mauricio H. Cornejo Martínez
Jan Elsen
Haci Baykara
Cecilia Paredes
Andrés Rigail
Refereed Paper: #165

Abstract:

This study deals with a comparison between water and air cured blended cement pastes at a W/B ratio of 0.3 after ageing for 91 days. SCMs like mordenite rich tuff, a mixture of clinoptilolite-heulandite-mordenite-calcite, and calcareous siltstone were blended with OPC at levels ranged from 5 to 27.5%. Using QXRD, TGA-DSC, as well as density measurements and compressive strength, some hydration parameters such as content of CH, anhydrous cement phases, calcite, and water in hydrates, density and the mechanical performance were determined. The results showed that hydration process of blended cement pastes was uncomplete at ages as late as 91 days regardless of curing conditions. The air cured cement pastes showed a less content of CH, water in hydrates, and compressive strength, but instead a higher density and content of carbonate-like minerals with respect to their water-cured counterparts. The pozzolanic reaction scarcely proceeded at a W/B ratio of 0.3 regardless of curing condition. Among the SCMs, mordenite rich tuff blended cement pastes presented the best compressive strength values, when was cured under water; the others showed better values of compressive strength in air curing condition.