Understanding the role of rheology in the plastic settlement and shrinkage cracking of early age concrete

Understanding the plastic (settlement/shrinkage) cracking phenomena of early-age concrete is important in-order to establish a holistic approach to minimise its occurrence. One of the factors associated with early-age concrete is the rheo-related behaviour which occur simultaneously within the timeframe known for plastic cracking. It is therefore useful to establish their links to broaden the knowledge of plastic cracking. This study is a novel evaluation of the influence of rheo-physical and rheo-viscoelastic behaviour on the plastic cracking behaviour by systematically altering these behaviours of formulated concrete mixes and extensively characterising them. The theory and frameworks for linking the behaviours were presented and established via statistical and analytical approaches. Significant rheo-related parameters found to influence plastic cracking phenomena include yield stress, structuration, creep and stress relaxation. The rheo-mechanics modelling suggests that the plastic cracking initiation tends to be a ductile failure that is pressure insensitive and sufficiently represented by von Mises criteria. This study opens up a consciousness to start evaluating mitigation strategies directed towards the materials optimisation of concrete mixtures to minimise the occurrence of plastic cracking in early-age concrete.