Engineering and durability properties of slag–dolomite geopolymer mortars

Ground-granulated blast-furnace slag and dolomite are by-products from the steel manufacturing and rock crushing industries, respectively. The addition of dolomite to a slag-based geopolymer matrix can improve its engineering properties and reduce disposal problems. This paper discusses the effect of alkali solution concentration, curing temperature and different proportions of slag and dolomite on the strength of geopolymer mortars. For maximum strength, the optimum ratio of slag and dolomite was found to be 70:30. Microstructural studies such as scanning electron microscopy and X-ray diffraction showed the co-existence of both calcium silicate hydrate and aluminosilicate gel in the slag–dolomite geopolymer matrix. Improved durability properties such as high resistance to water absorption, sorptivity and chemical attack can lead to the application of slag–dolomite geopolymer matrices in all types of structural elements.