Structural build-up, hydration and strength development of cement-based materials with accelerators

Fast structural build-up and strength development of fresh/hardened cement-based materials are always desired in many scenarios, where accelerators are often used. In this paper, the hydration, structural build-up and strength development of cement pates with different accelerators were investigated. The growth of static yield stress was used to characterize the structural build-up of fresh cement paste with 1% nano silica. Calorimetric curves, zeta potential and conductivity of pastes and strength development of mortars were also measured. Results showed that accelerators promote the reaction of C3S or C(3)A at different stages and in different mechanisms. Mechanical efficiency of C-S-H determined by growth of elastic modulus or yield stress over cumulated hydration heat may give wrong ranking on the efficiency of C-S-H. Apart from formation of C-S-H gel, structural build-up may originate from other sources. (C) 2020 Elsevier Ltd. All rights reserved.