Bleeding and evaporation in concrete slabs with sequential placement

Abstract

An analytical method that can predict the occurrence of plastic shrinkage cracking in sequentially placed concrete slabs is proposed on the basis of a numerical model introduced in previous studies by the current authors. The influence on plastic shrinkage cracking of design variables such as the number of placement steps and the time interval between layers is quantitatively analysed through parametric studies using the previously introduced analytical method. In addition, two regression equations that take into account the effect of the sequential placement on plastic shrinkage cracking in concrete slabs are introduced. The first estimates the time at which the surface of the concrete slab begins to dry and the second determines the critical time interval to prevent surface drying in each concrete layer. The timing of the curing and the sequence of concrete placement, which are important factors in the prevention of plastic shrinkage cracking, can be planned effectively using the introduced equations without rigorous analysis.