Effect of activator type and content on properties of alkali-activated slag mortars

Investigation of alkali activation of Turkish slag (AAS) was carried out using sodium silicate and sodium hydroxide activators within the scope of this study. The objective of the present work is to determine the SiO2/Na2O ratios (MS) and Na2O contents of the solutions on the development of workability, setting times, mechanical properties, drying shrinkage, water absorption characteristics and microstructure of alkali activated slag cement binders. Test results showed that MS and Na2O contents of activator solution are of great importance on the properties of AAS. Portland cement free high performance composite with compressive strength values about 100 MPa can easily be achieved by activation of slag without heat curing. Moreover, in case of activation by optimum MS ratio, sodium silicate activated AAS mortars present higher compressive strength, lower water absorption, higher workability, lower porosity and a wide range of setting times compared to NaOH activated AAS mortars and Portland cement mortar. Consequently, it can be said that this new binder is likely to have enormous potential to become an alternative to Portland cement.