Effect of alkali modulus on the compressive strength and ultrasonic pulse velocity of alkali-activated BFS/FS cement

Abstract

Portland cement, which has been used as an unrivaled binder material since its development has become one of major sources of greenhouse gas emission. Compared with the conventional cement, alkali-activated materials which based on the principle of activating precursor materials by means of alkali activators have comparable engineering properties and lower CO2 emission during its production. In this study, the effect of alkali modulus on the compressive strength and ultrasonic pulse velocity of granulated blast furnace slag/ferrochrome slag-based alkali-activated cement was investigated. Alkali-activated cement was produced from the mixture of a blast furnace slag and ferrochrome slag in proportion 80% and 20% respectively. Alkali modulus of 0.8, 1.0, 1.2, 1.4 were adopted in the test. Mortar specimens with the alkali modulus of 0.8 and 1 had very low strength after 3 days, while specimens with the modulus of 1.2 and 1.4 gained approximately half of their 28-day strength in the first three days.