🕑 Reading time: 1 minuteThe study of rheology of concrete provides information on properties of fresh concrete such as deformation, behavior of mix, and placement of mixed concrete. Rheology is a term that is mainly used for fluids whose flow properties are complicated in nature, other than fluids like liquids or gases. The term rheology may be defined as the study of the science of the flow and deformation of materials. In the concrete study, the concept of rheology may be applied to analyze the hardened concrete deformation, the behavior of cement paste and slurries, handling and placing of mixed concrete in its fresh state. Hence rheology is applied in all states of concrete (fresh to hardened).
Rheology of Fresh ConcreteWhen we deal with the rheology of fresh concrete, parameters that are to be considered are stability, mobility and compactability. These are the main factors which measure the suitability of a concrete mix. Now when dealing with rheology, the measurement is more based on stress, strain or rate of strain and the time factors. The stability, mobility and the compactability factors are expressed in terms of the forces or stresses dealing with the concrete mix. These are caused due to the transmission of mechanical stresses within it. The rheology of fresh concrete can be expressed by means of following flow chart in fig.1.
Fig.1. The Rheological Parameters of Fresh Concrete
Stability Parameter in Fresh Concrete RheologyStability is the property of a concrete mix when the aggregate particles within the mix possess a homogeneous dispersion and resemble a sampling in a random manner. This property is shown during its conveyance, placement as well as during compaction. Now there are two factors that measure the stability of the mixture. They are
Mobility Parameter in Rheology of ConcreteThe ability of the concrete fluid mix to flow is defined as its mobility. This mobility is happening by the action of mechanical stresses, which is also called as moment transfer. There are many factors that restrict the concrete flow like:
- Cohesive forces
- Frictional forces
- Viscous forces
- Shape and Texture of the aggregates used in the concrete mix
- The extent to which the mixture is rich
- Water - cement ratio
- The type of cement