Durability of concrete incorporating GGBS activated by water-glass

The environmental concerns related to the production of cement in terms of the energy consumption and the emission of CO2 lead to the search for more environmentally viable alternatives to cement. One of those alternative materials is ground granulated blast-furnace slag is used not only as a partial replacement to cement but also as the sole binder in the form of alkali-activated slag (AAS) to produce concrete. In addition to a control OPC mix, an OPC/slag mix with 60% cement replacement by GGBS, and also AAS mixes were prepared with slag as the sole binder, activated with water glass at two dosages, 4% and 6% Na2O (by weight of slag). Two types of water glass were used, one in a solution form and the other in a solid granules form. The two forms of the activator used were also of different silicate modulus (M-s); 1.65 for the solution form and 1.0 for the granule form. All the mixes had the same binder content and w/b = 0.48. This paper presents the results of the durability related tests that were carried out which included, chloride penetration resistance, porosity, carbonation, and alkali-silica reaction. The effect of the different parameters including the activator type and dosage are discussed. The results give indications on the good durability of alkali-activated slag concrete compared to conventional OPC concrete. @ 2007 Elsevier Ltd. All rights reserved.