Rheology of Fresh Concrete - A Review

Concrete is a heterogeneous, complex composite construction material. Fresh property of concrete is a critical property with significant effect on quality , cost of construction, strength, and durability. Even to this day the workability of fresh concrete is measured by empirical test, notably by slump test in spite of its drawbacks and sometimes with misleading results with less practical significance. There is an urgent need to characterize the flow of fresh concrete b y its rheological properties based on material science approach to overcome the inadequacies of the empirical test methods.Fluid rheology approach is the most fundamental one and describes the concrete flow by at least two parameters namely yield stress and plastic viscosity by considering fresh concrete as a Bingham fluid. Understanding and controlling the two fundamental fresh properties of concrete allow for more economical and better performing concrete mixes with the use of wide range of ingredients.This paper brings out the importance of rheology and advocates the use of fundamental science approach with two parameter tests along with advantages and limitations of using rheometers. Also highlights the use of concrete shear box static tests for wide range of workability requirements with the use of new and marginal materials in concrete industry.