Effects of microwave curing on the compressive strength development and hydration of cement-granulated blast furnace slag composite system

• Published in: Construction & building materials Vol. 270; p. 121432
• Main Authors: Kong, Yaning, Liu, Shuhua, Wang, Peiming
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 08.02.2021
• Subjects: Compressive strength; Granulated blast furnace slag; Hydration; Microstructure; Microwave curing; Microwave curing; Compressive strength; Hydration; Microstructure; Granulated blast furnace slag
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.121432

•Microwave curing shortens the curing period by reducing the delay time, heating rate and duration of high temperature.•The microwave has a non-thermal effect on the curing process of mortar.•Compared with steam curing, microwave curing can further accelerate the carbonation process.•Microwave improves the early-age strength by accelerating the hydration and reducing the porosity. To investigate the effects of microwave curing on the compressive strength development of mortar prepared with cement-Granulated Blast Furnace Slag (GBFS) composite binder and the underlying mechanism, the evolution of temperature and water to binder ratio during the curing, the hydration products and microstructure of composite system were studied. The results show that with the increase of the GBFS content the highest temperature achieved during microwave curing and the final water to binder ratios are reduced slightly. Through the surface tension test, the existence of non-thermal effect of microwave in composite system is indirectly proved. Compared with steam curing, microwave is easier to promote the carbonation of composite binder. In addition to the acceleration of hydration at early ages, the decrease of the number of harmful pores is an important factor for the improvement of compressive strength of mortar prepared with cement-GBFS composite binder.