Chapter 2
Concrete in Plastic State
- settlement , plastic shrinkage and bleeding. These occurrences will lead to future durability problem if they are not treated properly.
2.1 Settlement Cracks
2.1.1 Mechanisms
Settlement cracks arise due to the differential settlement of the concrete. Settlement of concrete happens during the plastic state when the concrete had been already placed but still does not reach its time of setting. Settlement is usually accompanied by bleeding of the concrete. Settlement cracks may occur by various mechanisms as stated below.
1) There are obstructing subjects to the settling concrete such as reinforcing steels (see the illustrations in Figs.2.1 and 2.2).
Fig.2.1. Occurrence of settlement crack due to obstruction by the reinforcing bar