Effects of source materials, fineness and curing methods on the strength development of alkali-activated binder

This study has investigated the strength development of alkali-activated binders (AAB) fabricated from slag, fly ash (FA), rice husk ash (RHA), and palm oil fuel ash (POFA). Materials being used as singular, binary and ternary compositions while Ca(OH)2, KOH and NaOH were used separately as a chemical activator. All the test results of AAB for 10 numbers of different mixes have been compared to ordinary Portland cement (OPC) mortar. Test result reveals that compressive strength of slag activated mortar with 5% NaOH (by weight of binder) achieves 88.2% compressive strength of OPC at 28 days. Among the 10 mixes, AAB4 containing 40% slag, 30% POFA and 30% RHA with 5% NaOH shows a significant compressive strength of 41.7 MPa at 28 days. Flexural strength of alkali-activated mortar with 5% NaOH seems to be acceptable compared with that of OPC mortar at 28 days. It is clearly observed that the strength development of AAB-mortar is greatly influenced by the types and fineness of materials and blending of materials. In contrast, the compressive strength of AAB-mortar is comparatively less influenced by employing different curing methods like water, wetted jute bag and air curing.