The engineering properties and microstructure development of cement mortar containing high volume of inter-grinded GGBS and PFA cured at ambient temperature

The high consumption of Portland cement in concrete production had contributed to a significant carbon dioxide emission to the environment. The application aluminosilicate rich waste material in the manufacturing of Portland cement as partial replacement material has become an alternative to minimize the carbon dioxide emission and at the same time to solve waste management problems through recycling of industrial waste material. The study is mainly aimed to maximize the level of cement replacement of ground granulated blast furnace slag (GGBS) and pulverized fuel ash (PFA) in the production of cement mortar through hybridization and mechanical activation. The laboratory testing program includes bulk density test, compressive strength test, flexural strength test, ultrasonic pulse velocity test (UPV) and dynamic modulus test from 7 days of curing age up to 90 days. Besides, scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy test (EDX) have been performed in order to determine the microstructure development of the paste sample. It is observed that the inter-grinding activation method is able to further enhance the reactivity of the geopolymer material from the aspect of increase in mechanical strength and improve in durability performance.