Study of Partial Replacement of Sand with Wanza Sawdust to Produce Concrete
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Date
2019-06
Authors
Getish, Lemma
Journal Title
Journal ISSN
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Publisher
Addis Ababa University
Abstract
Concrete is a composite material of which 60-75% by volume is aggregates. Out of this
volume, 30-40% is composed of fine aggregates. Fine aggregate is one of the predominant
contents of concrete usually natural river sand is used as the fine aggregate. Wanza Sawdust
which is the byproduct Wanza wood is abundantly available in Tepi, Ethiopia. However,
there is no sand source in Tepi, Ethiopia. Therefore, this research tried to study the possibility
of sawdust to replace sand in the production of concrete.
The objective of this experimental study was to investigate the effect of using sawdust as an
alternative for fine aggregate in concrete production and by determining the optimum
replacement of sand with sawdust that can be acceptable for the production of concrete. The
research studied workability, setting time, density, compressive strength and water
Penetration of C-20 class of concrete produced by replacing 5%, 10%, 15%, 20% and 25% by
volume of sand with sawdust.
In studying the properties of concretes, a total of twelve concrete mixes made with OPC and
PPC were prepared by replacing sand with sawdust. The investigation of this thesis has
revealed that compressive strengths of OPC concrete mixes with 5%, 10% and 15% sand
with sawdust replacement satisfy the 20MPa cube Compressive strength compliance criteria
of ACI 301, Specifications for Structural Concrete, at 28 days. The strengths achieved, 21.4,
20.8 and 20.2MPa respectively, are greater than the specified .At 56 days the compressive
strengths of PPC concrete mixes with 5%, 10% and 15% sawdust replacement satisfy the
compliance criteria of ACI 301. The strengths achieved, 21.8MPa, 20.8MPa and 20.4MPa
respectively, are greater than the specified.
Sawdust retarded the hydration reaction of cement because the setting time of concrete
increased when percentage replacement of sand with sawdust increased. The slump of the
concrete decreased through percentage replacement of sand with sawdust and also the density of concrete decreased with the percentage replacement of sand with sawdust. The water
permeability of concrete increased through percentage replacement of sand with sawdust.
Finally, based on 15% optimum replacement of sand with sawdust, the material cost of
concrete with sawdust was found lower than concrete without sawdust. In one meter cube, the
cost of concrete made with sawdust decreased by 49.8 birr or 3.78% than concrete without
sawdust.
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Keywords
sand, sawdust, partial replacement