Influence of alkali concentration and modulus on compressive strength of alkali activated slag concrete.

Alkali activated slag (AAS) concretes were manufactured by using raw materials such as blast furnace slag from Northern Ireland of UK and water glass. Influence of alkali concentration and modulus of water glass on properties of the AAS concretes was studied. The results show that slump of AAS concretes increased with the increase of alkali concentration. Modulus had no significant influence on the slump of AAS concretes when it is relative small (4% and 6%). When alkali concentration was 8%,slump of AAS concretes increased with the increase of modulus. When 3d compressive strength of AAS concretes was considered,alkali concentration of water glass should not be lower than 6%,and the optimum modulus was around 1.0. While regarding to the compressive strength at 28d and afterwards,the optimum alkali concentration and modulus were 6% and 1.5, respectively. With the increase of curing age,compressive strength of AAS concretes increased in a logarithm mode. Their 28 d compressive strength could reach to 75% of their 91 d counterpart. After 28days,compressive strength of AAS concretes increased slowly. [ABSTRACT FROM AUTHOR]