EXPERIMENTAL STUDY ON BOND STRENGTH OF REBAR IN HIGH PERFORMANCE CONCRETE CONTAINING ULTRA-FINE FLY ASH

摘要

The partially replacement of cement by ultra-fine fly ash(UFA)can not only improve workability of high performance concrete(HPC),but also affect the mechanical properties of HPC.This paper focuses on the influence of UFA on the bond strength of rebars in high performance concrete with high fluidity.The bond behaviour was tested with pull-out specimens under monotonic loading .The diameter of deformed rebars is 14 mm and that of plain round rebars are 14mm and 16 mm,respectively.The replacement levels of UFA were 10,20,30,40,and 50%,respectively.Four different water-binder ratio was chosen.The tests results show that the bond strength in HPC decreases with the increase of UFA content at a given water-binder ratio.When the compressive strength is equal to each other,the bond strength in HPC containing UFA is a little higher than that of ordinary concrete without UFA.The bond strength of deformed rebars is higher than that of plain rebars.The bond strength of rebars linearly increases with the concrete compressive strength.