Effect of calcium sulfoaluminate and MgO expansive agent on the mechanical strength and crack resistance of concrete. (13th September 2021)

• Record Type: Journal Article
• Authors: Guo, Jinjun; Zhang, Shiwei; Qi, Cuige; Cheng, Lin; Yang, Lin
• Is Part Of: Construction & building materials. Volume 299(2021)
• Publication Date: 2021-09-13
• Subjects: Shrinkage-compensating concrete -- MgO expansive agent -- Crack resistance -- Durability -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.123833
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Calcium sulfoaluminate and MgO expansive agents were used together in concrete. Effect of the blended expansive agent on the mechanical strength was investigated. The restricted expansion and dry shrinkage of concrete were continuously monitored. Crack resistance of concrete with the blended expansive agent was evaluated. Abstract: This work explored effects of calcium sulfoaluminate (CSA) and MgO blended expansive agent on the mechanical strength and deformation of concrete. What's more, the mechanism was investigated using SEM and XRD analysis. Results show that the addition of MgO is beneficial to improve the later strength of concrete. When the MgO content exceeds 2%, the mechanical strength of concrete at the later stage increases significantly; however, it begins to reduce when the MgO content is more than 5%. All results illustrate that the optimum mass ratio of CSA and MgO is 2:1, and the concrete shows a certain expansion at all stages, which also reduces the drying shrinkage at the later stage. Meanwhile, with the optimum mass ratio of CSA and MgO, the crack resistance of concrete can be improved by 97–127 % compared with a single expansive agent.