Effect of thermal cycling on the properties of high-performance concrete: Microstructure and mechanism. (20th May 2020)

• Record Type: Journal Article
• Authors: An, Mingzhe; Huang, Hanfeng; Wang, Yue; Zhao, Guanyuan
• Is Part Of: Construction & building materials. Volume 243(2020)
• Publication Date: 2020-05-20
• Subjects: Thermal cycling -- High-performance concrete -- Interfacial transition zone -- Sorptivity -- Cracking -- Mechanical properties; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.118310
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Effect of thermal cycles on micro- and macro-property of concrete studied. The interfacial transition zone microstructure determined the cycling performance. Higher-strength grade concrete more affected by thermal cycling. Thermal cycling induced the generation, propagation, and connection of new microcracks, and growth of existing microcracks. Abstract: The effect of thermal cycling on high-performance concrete (HPC) was evaluated by analyzing the mechanical properties and capillary water absorption considering the microstructural changes of the cement matrix and interfacial transition zone (ITZ). Backscattered electron (BSE) imaging and nanoindentation methods were used to study the mechanism behind the changes in HPC properties during thermal cycling. Under thermal cycling, the micromechanical properties of the cement matrix, and especially the ITZ, degraded. With increasing thermal cycles, the mechanical properties of all HPC grades decreased, especially for higher-strength HPC, because of major deterioration of the ITZ microstructure. Under thermal cycling, enhanced microcracking resulted in a significant increase in initial sorptivity and decrease in secondary sorptivity, especially for higher-strength HPC. The expansion of existing microcracks and formation of new ones during thermal cycling resulted in an increase in water penetration depths, and degraded micro- and macro-properties.