The importance of C-A-S-H Surface Chemistry on Chloride Resistance of Slag-Blended Cement

Author(s): Elakneswaran Yogarajah and Toyoharu Nawa
Paper category: Proceedings
Book title: Proceeding of the 71st RILEM Annual Week & ICACMS 2017
Editor(s): Manu Santhanam, Ravindra Gettu, Radhakrishna G. Pillai, Sunitha K. Nayar
ISBN:978-2-35158-195-7, 978-2-35158-190-2 (Set)
e-ISBN: 978-2-35158-191-9
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 323-332
Total Pages: 10
Language : English

Abstract: The main reaction product in Portland cement (PC) with supplementary cementitious materials or Ca-rich modern cements is a calcium aluminosilicate hydrate (C-A-S-H) gel. Physicochemical and surface electrical properties of C-A-S-H gel are significantly different from the gel formed in conventional PC system with different capacity for immobilization of various ions and their transport into concrete. In this study, surface electrical properties of C- A-S-H and their influences on chloride binding and transport into slag-blended cement have been studied. The zeta potential results show that surface electrical properties of slag-blended cement are in between hydrated PC and calcium silicate hydrate (C-S-H) with Ca/Si of 1.0. A two-layer surface complexation model was used to predict chloride binding in slag-blended cement. The predicted total binding of chloride shows good agreement with batch experimental data, follows a Freundlich isotherm. A multi–component diffusion model coupled with thermodynamic and surface complexation reactions is applied to predict chloride ingress in slag-blended cement. The simulated results are compared with experimental data for diffusion of chloride.

Online publication :2017
Publication type :full_text
Public price (Euros) : 0.00