EFFECT OF FLY ASH, LIMESTONE POWDER AND BOTTOM ASH ON SHRINKAGE CRACKING BEHAVIOR OF CONCRETE

Abstract

This research was aimed to study the cracking behavior under restrained
shrinkage condition of concrete containing fly ash, limestone powder and
bottom ash. The bottom ash was used as an internal curing material. The
cracking behaviors of concrete that were studied in this research consist of
the cracking age of concrete under the uniaxially restrained shrinkage test,
free shrinkage, tensile strength and compressive strength of concrete. In this
study, the weight percentages of replacement of cement by fly ash were 0,
30 and 50%. For limestone powder, the replacement percentages were 0,
10%. The volume percentages of replacement of fine aggregate by the
bottom ash were 10 and 30%. The water to binder ratio of 0.55 was used in
this investigation. The results indicated that the use of fly ash could reduce
the shrinkage while the shrinkage of limestone powder concrete slightly
increased. The use of fly ash and limestone powder increased the cracking
age of concrete. Moreover, the cracking age of concrete increases with the
increase of fly ash content. The use of bottom ash as internal curing can
reduce autogenous shrinkage and can increase cracking age of concrete. The
compressive strength reduces with increase of fly ash and bottom ash
content.