Influence of drying conditions on the contact-hardening behaviours of calcium silicate hydrate powder. (1st April 2017)

• Record Type: Journal Article
• Authors: Wang, Shuping; Peng, Xiaoqin; Tao, Zhilong; Tang, Luping; Zeng, Lu
• Is Part Of: Construction & building materials. Volume 136(2017)
• Page Start: 465
• Page End: 473
• Publication Date: 2017-04-01
• Subjects: Drying conditions -- Calcium silicate hydrate -- Contact-hardening -- Microstructure -- Moisture content -- Particle-particle bonding; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2017.01.037
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Contact-hardening behaviour of C-S-H treated at varied drying conditions is described. Physical properties and microstructure of C-S-H are related to the drying conditions. Oven-drying at 80 °C is beneficial to the strength development of the compacts. Moisture content of C-S-H is the key factor to the contact-hardening of the material. Abstract: Contact-hardening is a new type of binding property for amorphous calcium silicate hydrate (C-S-H) with which a hardened specimen can be prepared in a few minutes by compressing C-S-H powders directly. However, the relation between contact-hardening behaviours and the drying conditions of powders is still poorly understood. In this study, the influence of air-drying and oven-drying on the physical properties and microstructure of hydrothermally synthesised C-S-H powders were investigated. The results provide further insight into the contact-hardening behaviours of these powders by measuring the bulk density, mechanical strength and water-resistant properties of the compacts. Factors affecting particle-particle contact and hardening of C-S-H powders are discussed in parallel with the mechanical properties and microstructure of the compacts. The result highlights that the moisture content, which is highly related to the drying conditions, is essential to contact hardening of C-S-H.