From Thixotropy of Self-Consolidating Concrete to SmartCast and 3D Printing

Abstract

Compared with conventional vibrating concrete, self-consolidating concrete (SCC) is more flowable and can consolidate under its own weight. Therefore, it introduces many advantages in construction applications. These include decreasing labor work for casting, better quality control and enhancing hardened properties. However, challenges still remain, such as issues relating to formwork pressure and multi-layer casting. Each of these issues is closely related to the property of thixotropy. For SCC, as well as other concrete systems, it is about balancing sufficient flowability during casting and rate of structural buildup after placement. For instance, relating to the issue of SCC formwork, it is ideal for the material to be highly flowable to achieve rapid casting, but then exhibiting high rate of structural buildup to reduce formwork pressure. This can reduce the cost of formwork and reduce the risk of formwork failure. It is apparent that accurately quantifying the two aspects of thixotropy, i.e. structuration and destructuration, is key to tackling these challenges in field application.