A comparative investigation into lime activated ground granulated blast furnace slag as a sustainable alternative to Portland cement in masonry mortars

Portland cement production is known to have a detrimental impact on the global environment and subsequently the construction industry has made moves to introduce more sustainable materials and practices. The introduction of hydraulic lime based mortars for masonry being one example. Nevertheless there are other binders that are also deemed sustainable, as for example, lime or alkali activated ground granulated blast furnace slag (GGBS). Very little information is available on the performance of lime activated GGBS mortars, especially their tensile bond strength characteristics. This project was designed to compare the performance characteristics and properties of two sets of mortar mixes. One set of samples was based on traditional Portland cement, lime, sand mixes. The other set was based on GGBS, lime, sand mixes, where the lime content served as a workability agent and as an activator for the GGBS. Tensile, flexural and compressive samples were fabricated from both mortar sets and tested at 28 days. The results indicated that mortar mixes containing lime activated GGBS could be used as sustainable alternatives to Portland cement based mortars for masonry applications as they showed similar properties to their Portland cement based counterparts.