Influence of added water and fly ash content on the characteristics, properties and early-age cracking sensitivity of alkali-activated slag/fly ash concrete cured at ambient temperature

For an appropriate air void system, good mechanical properties and low porosity/microcracking in alkali-activated binder systems, appropriate slag/fly ash proportioning, water and admixture contents are needed. Air entraining admixture dosages of up to 10 times the recommended dosage were necessary to obtain minimal air void properties similar to what is needed for normal portland cement concretes subjected to freezing conditions. Increasing added water resulted in increasing absorption and decreasing crack counts in concrete. Increasing fly ash contents resulted in increasing absorption and decreasing early-age crack counts. Increasing both added water and fly ash content resulted in less autogenous shrinkage.