Non-shrink, self-flowing dry mortar with a compressive strength of over 80 MPa using fine blast furnace slag

Abstract

Non-shrink self-flowing dry mortar is commonly used in Vietnam to repair hollow, damaged concrete structures, or fill structural gaps. The manufacturing of non-shrink self-flowing mortar requires the use of many different types of additives. In addition, it is difficult to combine them to meet both technical and economic requirements. This article presents the results of research on producing non-shrink self-flowing dry mortar using fine blast furnace slag with a compressive strength after 28 days of over 80MPa. The input materials were all selected in dry powder form. The water/mortar ratio was 0,13. The fine blast furnace slag contents used were 15%, 20%, and 25%, and the powdered polycarboxylate superplasticizer was used at a content of 0.23% compared to the binder. In practice, the amount of water and superplasticizer must be chosen to maintain stability for the workability of dry mortar. The experimental results on flow, compressive strength, flexural tensile strength, and shrinkage show that the non-shrink self-flowing dry mortar meets the requirements of packaged dry mortar.