Abstract: Industrial steel slag can be used as an additive in concrete as it contains such minerals as C₂S and C₃S which have similar gelling properties with cement clinker. Nevertheless, excessive dosage of industrial steel slag would result in inferior stability because it also contains f-CaO and f-MgO. To better utilize fine aggregate of steel slag in cement mortar, we performed drying shrinkage test to investigate the influence of steel slag on the long-term drying shrinkage performance of cement mortar at different curing ages under different curing conditions. Test results demonstrated that under standard curing condition, the drying shrinkage rate of cement mortar reached the lowest when added with 60% single steel slag powder, or 70% single steel slag sand, or 20% powder mixed with 40% sand, or 30% powder mixed with 60% sand; under constant temperature curing condition, the long-term dry shrinkage value of cement mortar was the lowest when 35% of steel slag powder was mixed with 40% steel slag sand.

Key words: cement mortar, steel slag powder, steel slag sand, drying shrinkage performance, drying shrinkage rate