Study on a high strength ternary binder cured under different conditions

• New proportion of the ternary binder based on OPC–CAC–CS was created.
• Five curing conditions were used for the mortars.
• The strength and expansion were influenced by both steam curing and drying curing conditions.
• A relationship between strength, expansion and hydration products had been found.

High strength ternary binder based on ordinary Portland cement (OPC), calcium aluminate cement (CAC) and calcium sulfate (CS) is used as repair materials. However, temperature and humidity govern the strength of this binder. In addition, the proportions of OPC–CAC–CS have strong influence on the fluidity, setting time and mechanical properties of the system. The mortars with the ternary binder were cured under different conditions in this study. Then the compressive strength and the restrained expansion rate at different ages were evaluated. The results show that high strength binder was obtained using the proportion of 82%–10%–8% of the OPC–CAC–CS system. The early compressive strength under steam curing was higher than that of under standard curing, but a contrary result was occurred at 28 days and the strength did not decrease under dry curing. The expansion rates of the mortars increased with the increase of time under both the standard and the steam curing, but decreased in the dry oven. XRD, TG and SEM show that a relationship between the content and microstructure of ettringite and calcium hydroxide was found when the samples were cured under different temperatures and humidity.