Effects of C-S-H Nano-Crystals on Early Strength Development in Concrete

Author(s): S. Das, S. Ray, and S. Sarkar
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: 111-118
Total Pages: 1
Language : English

Abstract: Early strength gaining of concrete plays a key role in faster production cycle of pre-cast structural components. Use of conventional methods for accelerating the concrete hardening process produces environmental and durability related problems. In this work, an attempt has been made to utilize pre-formed C-S-H nano-crystals as a sustainable admixture to concrete for its early strength development. The nano-crystals were obtained through chemical synthesis from locally available agricultural waste material. The synthesized crystals when added to concrete, produced numerous nucleation sites in addition to the regular surface sites of the cement particles and hence, accelerated the precipitation process of the hydration products resulting in accelerated hardening during early strength generation process. C-S-H nanocrystals lose its effectiveness as they are prone to agglomeration due to their small size. In order to optimize their effectiveness by preventing agglomeration, the synthesized crystals were kept dispersed using different dispersing agents. In the present study, three types of dispersing agent have been tried namely, starch solution, Cetyltrimethyllammonium bromide (CTAB), and sodium lauryl sulphate (SLS). It was observed that the use of CTAB and SLS had significant retardation effect on the setting time, whereas the C-S-H nano-crystals in starch solution showed overall improvement in accelerated gain of strength. Keywords: Setting time, C-S-H, dispersant, zeta potential

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