Influence of superfine ettringite on the properties of sulphoaluminate cement-based grouting materials. (30th March 2018)

• Record Type: Journal Article
• Authors: Li, Haiyan; Guan, Xuemao; Zhang, Xuyang; Ge, Peng; Hu, Xingxing; Zou, Dinghua
• Is Part Of: Construction & building materials. Volume 166(2018)
• Page Start: 723
• Page End: 731
• Publication Date: 2018-03-30
• Subjects: Superfine ettringite -- Compressive strength -- Setting time -- Sulphoaluminate cement -- Grouting materials; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2018.02.013
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: S-ettringite was prepared via SNAS method by introduction of citric acid. The 4-h compressive strength increased by 380% when adding 4 wt% S-ettringite. Decline of setting time of CBGM paste was shown by the addition of S-ettringite. Effect of S-ettringite on the hydration and microstructure of CBGM paste was studied. Due to crystallization inducting effect and seed effect S-ettringite changed the hydration of paste. Abstract: Superfine ettringite (S-ettringite) synthesized in this research presents same structure with the ettringite produced by the hydration of cement, which is expected to promote the hydration of sulphoaluminate cement-based materials. There are few literature reports on laboratory synthesis of superfine ettringite. In this paper, preparation of S-ettringite via separate nucleation and aging steps method by introduction of citric acid is presented. The effect of the S-ettringite on hydration, microstructure and properties of CSA cement-based grouting materials (CBGM) was experimentally investigated. Results show that specimens containing S-ettringite displayed a significant improved performance with regard to compressive strength at early and later ages and setting time. Compared to the control specimen, 4-h compressive strength increased by 380% and initial setting time shortened by 55.6% when 4 wt% S-ettringite was added, respectively. Due to the crystallization inducting effect and seed effect, the addition of S-ettringite changed the morphology of ettringite, and meanwhile promoted the hydration exothermic rate and increased the amount of hydration products, which thus generate higher compressive strength and shorter setting time.