Carbonation-hardening properties and ITZ microstructure of low-calcium CO2 sequestration binder mortar. (20th June 2022)

• Record Type: Journal Article
• Authors: Chang, Xiangxiang; Liu, Songhui; Zhang, Cheng; Shen, Peiliang; Xuan, Dongxing; Guan, Xuemao; Shi, Caijun
• Is Part Of: Construction & building materials. Volume 336(2022)
• Publication Date: 2022-06-20
• Subjects: Low calcium CO2 sequestration binder -- Carbonation -- Interfacial transition zone -- Microstructure; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2022.127589
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: A new low-calcium carbon dioxide sequestering binder was prepared at 1275 °C. The carbonation degree at the ITZ is higher than that of the LC-CSB paste. CaCO3 will be enriched at the ITZ with the increase of carbonation duration. Abstract: To produce high-strength prefabricated building materials and reduce their CO2 emissions, a new low calcium CO2 sequestration binder (LC-CSB) was prepared by calcination of industrial raw materials limestone and sandstone at 1275 °C. The physical and mechanical properties development of the LC-CSB mortar was investigated at different carbonation durations (5 min, 10 min, 30 min, 1 h, 8 h, 24 h). Moreover, the microstructure and micromechanical properties of the interfacial transition zone (ITZ) between carbonated LC-CSB paste and siliceous river sand aggregate were revealed by SEM and nanoindentation. The results showed that the compressive strength of the LC-CSB mortar reached 43.2 MPa after carbonation for 24 h. The ITZ was more easily carbonated than the LC-CSB paste, and the calcite crystals generated after carbonation will be enriched at the ITZ with the increase of carbonation duration, while the porosity was significantly reduced.