EFFECT OF BOTTOM ASH ON AUTOGENOUS SHRINKAGE OF BINARY BINDER MORTAR

Abstract

In this study, effect of bottom ash as a partial replacement of fine aggregate
on autogenous shrinkage of cement-only and binary binder mortar was
investigated. The autogenous shrinkage was studied in mortar with the river
sand partially replaced with bottom ash at 0%, 10%, 20% and 30% by
volume. Two types of bottom ash having low water retainability (18.8%)
and high water retainability (29.6%) were used in this study. The influence
of types of cement (Type I, III and V) on autogenous shrinkage of mortar
with bottom ash was investigated. The control mixture included only
Ordinary Portland Cement (OPC) while the binary mixtures were prepared
by blending the OPC with fly ash. The weight percentage of replacement of
cement by fly ash was 30%. The results indicated that the use of bottom ash
could reduce autogenous shrinkage of mortar. The autogenous shrinkage
decreased with the increase of bottom ash content. The high water
retainability bottom ash was more effective to reduce autogenous shrinkage
than that of the low water retainability bottom ash. These phenomena had
also been found in the binary binder system. The use of bottom ash in fly
ash-cement mortar also reduced autogenous shrinkage.