Bond performance of repair mortar made with magnesium phosphate cement and ferroaluminate cement. (12th April 2021)

• Record Type: Journal Article
• Authors: Jia, Liang; Zhao, Fangli; Yao, Kai; Du, Hongjian
• Is Part Of: Construction & building materials. Volume 279(2021)
• Publication Date: 2021-04-12
• Subjects: Magnesium phosphate cement -- Flexural bond strength -- Bond interface -- Water resistance -- Model; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2021.122398
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Influences of the FAC content and curing conditions on the bond performance of MPC-FAC composite were studied. The chemical composition and microstructure of the fracture interface were analyzed. Enhancement mechanism between MPC-FAC mortar and OPC substrate was characterized. Abstract: This paper is aimed to investigate the bond performance of mortar with magnesium phosphate cement (MPC) as a novel-type repair material. This is achieved by mixing ferroaluminate cement (FAC) with MPC to prepare composite cement (MPC-FAC). Under standard and water curing conditions, the properties of MPC-FAC composite including setting time, ph, compressive and flexural bond strengths were tested. Experimental results show that adding FAC could significantly improve the compressive strength, flexural bond strength, water-resistance of FAC-MPC composite. Rough substrate interface contributes to the flexural bond strength of MPC-FAC mortar and OPC substrate. SEM-EDS was used to analyze the bond interface and micro-morphology of MPC-FAC before and after water immersion respectively. It was shown that the main reason for better bond performance is that the interface structure of MPC-40FAC composite and OPC substrate is more compacted, while MPC-40FAC composite microstructure is more integrated after water immersion. The three-zone model of the bond between OPC substrate and MPC-FAC repair material is also presented, which indicates that the interface bond behavior includes mechanical interlock, permeating and filling and secondary hydration. These promising results indicate that MPC-FAC composite can be used as a rapid-hardening repair material in the practical field.