Effect of BaCl2 on the hydration properties of ultrahigh performance geopolymer concrete

• Published in: Construction & building materials 2023-11, Vol.403, p.133074, Article 133074
• Main Authors: Li, Qing, Wang, Jinbang, Zhou, Zonghui, Du, Peng, Zhang, Xiuzhi
• Format: Article
• Language: English
• Subjects: Ground granulated blast furnace slag; Mechanical properties; Rheology; Ultrahigh performance geopolymer concrete; Workability
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.133074

•Ultrahigh performance geopolymer concrete was prepared.•Effects of BaCl2 on the setting time, hydration property and rheological property of UHPGC were investigated.•The retarding mechanism of setting was investigated by hydration heat, rheological property, SEM and TG.•The working performance of UHPGC is improved effectively. Ultrahigh performance geopolymer concrete (UHPGC) is a new construction material with ultrahigh mechanical properties and excellent durability. However, UHPGC is difficult to use in practical engineering due to its short setting time and high viscosity. Therefore, increasing the setting time and improving the working performance of UHPGC is critical. In this paper, effects of BaCl2 on the setting time, hydration property, rheological property and mechanical property of UHPGC were investigated by testing the setting time, fluidity, plastic viscosity, compressive and flexural strength. Furthermore, the retarding mechanism of setting was also discussed. The results indicated that with increasing of BaCl2 content, the early hydration of UHPGC was delayed, and the compressive strength first increased and then decreased. SiO32− ions were consumed by the incorporation of BaCl2 and generated a large amount of BaSiO3 precipitate, which wrapped the slag particles, and the further hydration of slag was delayed. Consequently, the plastic viscosity and yield stress were reduced, the fluidity was improved, and the working performance was enhanced.