Evaluation of monomer ratio on performance of GGBFS-RHA alkali-activated concretes

摘要

In his research study, alkali-activated concrete (MC) are prepared by using ground granulated blast furnace slag (GGBFS) as industrial material and rice husk ash (RHA) as agricultural solid waste. The mixes were constructed with 20% cement paste and 80% GGBFS-RHA alkali-activated paste, and with 100% GGBFS-RHA alkali-activated paste. Furthermore, the alkali activator dosage ratios were considered to be 2, 2.5 and 3. The compressive and elastic modulus, water absorption, ultrasonic pulse velocity (UPV) and drying shrinkage tests were performed to evaluate different characteristics of MC. Scanning electron microscope (SEM) test was also carried out to have an insight in the microstructure of mixes. The test results showed that the mechanical properties can be improved when alkali-activated paste was used completely. The durability test results indicated that using alkali-activated paste improved the pastes by the reduction of permeability. It was also inferred from the results that the increasing the monomer ratio in alkali-activated paste resulted in a significant reduction in shrinkage values. In addition, it was found that using GGBFS-RHA pastes resulted in pore refinement in the interfacial zones. It was also reported that the interfacial transition zone (ITZ) between the cement and alkali-activated pastes became compacted by increasing the monomer ratios from 2 to 3 that water permeability can be decreased as a result. (C) 2019 Elsevier Ltd. All rights reserved.