Abstract:
One of the most important ingredients of hollow concrete block (HCB) is aggregate that differ
depending on their classification. The most common aggregate used for HCB are pumice and
scoria. As many researchers conducted the concrete produced from both aggregate are light
weight and also the aggregate in hollow concrete blocks are partially or totally replaced with
different types of materials and wastage of some product to reduce the environmental pollution.
The main objective of this study was to investigate the relevance of hollow concrete block
produced as replacement of scoria with wastage of Ambo sandstone. Specifically it
focused in determining the physical properties of wastage of Ambo sandstone aggregates and
scoria, determine compressive strength of hollow concrete blocks produced at each replacement
and to compare the production cost. In addition workability, unit weight and water absorption of
hollow concrete were conducted.
This experimental study was conducted by preparing of hollow concrete blocks test sample and
108 HCB sample was produced. The test sample of hollow concrete blocks was produced by
using mix proportion 1:4:2 of cement, scoria and 01 crushed aggregate. Out of the four parts of
scoria aggregate, scoria was replaced with 20, 40, 60, 80 and 100% amount of wastage of Ambo
sandstone by volume.
According to this study, the hollow concrete block with 100% scoria achieved 3.85Mpa mean
compressive strength and the hollow concrete block with 100% wastage of Ambo sandstone
achieved 6.83Mpa mean compressive strength. The production cost of all hollow concrete blocks
with wastage of Ambo sandstone was lower than hollow concrete block without wastage of Ambo
sandstone. According to the water absorption comparison made the hollow concrete block with
wastage of Ambo sandstone was found lesser absorptive and heavier than without wastage of
Ambo sandstone.
Hollow concrete block with wastage of Ambo sandstone in this study has achieved better cost
reduction in production cost, smaller increase in weight, reduction in water absorption and high
increase in compressive strength than hollow concrete blocks without wastage of Ambo
sandstone. The study further recommended to the construction industry in Ambo and around
Ambo town to use wastage of Ambo sandstone for production hollow concrete blocks instead of
other aggregate.
