Characterization of self-consolidating concrete (SCC) rheological properties

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New developments in concrete technology have resulted in changes in the types of concrete used in civil engineering applications as well as the performance requirements. Use of new cements and new mineral and chemical admixtures have led to the development of high performance concrete (HPC) and self-consolidating concrete (SCC). HPC and SCC present numerous advantages such as high strength, high elastic modulus, less bleeding, less creep, and high durability. For example, SCC is a highly flowable concrete that can spread easily and self consolidate under its own weight without segregation. Stricter performance requirements, mainly durability, have also been imposed on these concrete technologies to ensure longevity. At present, standard test methods have not been developed to ensure quality of the fresh concrete and its compliance with durability and other structural requirements. Quality of fresh concrete can be characterized by its homogeneity, and the ease with which it can be mixed, transported, compacted and finished. Rheology, which is defined as the science of deformation and flow of matter with time, provides the material properties for controlling the quality of concrete. At present, concrete rheology continues to be qualitatively characterized by terms such as workability, flowability, compactability, stability, finishability, pumpability, and consistency, without a proper reference to fundamental measurements of properties. To overcome these inadequacies, a fundamental and quantitative approach is proposed to adequately describe the flow of fresh SCC concrete. Predicting concrete rheological properties using the mixture composition is a novel approach. Other significant future outcomes will be the development of a holistic approach for designing the optimum concrete mixture proportions with the desired rheological properties, mechanical properties and durability. These developments will enhance the economic viability of concrete, will reduce waste and conserve natural resources, all leading to sustainable concrete infrastructure.