Natural Zeolites as SCMs: Challenges and solutions

Author(s):Maria Juenger, Lisa Burris, Saamiya Seraj, Raissa Ferron
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference
Materials, Systems and Structures in Civil Engineering 2016
Segment on Concrete with Supplementary Cementitious Materials
Editor(s): Ole M. Jensen, Konstantin Kovler and Nele De Belie
ISBN:978-2-35158-178-0
e-ISBN: 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 146-153
Total Pages: 8
Language : English

Abstract: Abstract
Natural zeolites are abundant in many regions. While high purity zeolites are used in other industries, low purity zeolites are underutilized and can find beneficial use as supplementary cementitious materials (SCMs) in concrete. However, these low purity, natural zeolites present challenges as SCMs because of their high water demand and variable reactivity. In this paper, the effects of two natural clinoptilolite zeolites on the properties of cement-based materials are discussed. Further, the role of chemical and physical treatments to the zeolites is addressed. The results show that both zeolites are pozzolanically reactive, increasing the compressive strength of mortars and consuming calcium hydroxide, with the coarser zeolite showing less promising performance. A calcination pre-treatment at 800oC had little effect on the pozzolanic reactivity of the zeolites tested; however, a considerable reduction in flow resistance of the pastes containing the calcined zeolites occurred compared to the pastes containing uncalcined zeolites. Pre-treating the coarser zeolite in acid solutions improved reactivity through increased surface area and increased SiO2/Al2O3 ratio. Milling the coarser zeolite improved pozzolanic reactivity by reducing particle size.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00