"Structure of concrete "notes for civil engineering 4th semester

Transition zone in concrete :

The transition zone is also called strength limiting phase. The quality of paste is poor here. This zone is a plane of weakness and therefore has great influence on mechanical behaviour of concrete. There takes place development of micro cracks due to the shrinkage and temperature variation. 

Effect of transition zone in properties of concrete are as follows :

(1)This phase is considered as the strength limiting weak phase. 

(2)Concrete tends brittle behaviour in tension and tough behavior in compression. 

(3)Micr ocracks are caused by shrinkage and variation in temperature. 

(4)For the given w/c ratio or cement content hydration strength decrease with increase in coarse aggregate size.