| Summary: | In this study, the properties of concrete containing internal curing agent under different
curing conditions were investigated. Saw dust is a waste material generated as a byproduct
from the wood related industries. The saw dust was pre-saturated to act as an
internal curing agent and silica fume was added in this research. The internal curing agent
(saturated saw dust) was used to partially replace 2.5%, 5.0% and 7.5% of volume of
sand and 15% silica fume was incorporated as partial replacement of the mass of cement.
The water/cement ratio used in this research is 0.5. The concrete samples were subjected
to three different curing conditions (water tank, dry curing room at room temperature and
40°C oven) after demoulding. From the results, the workability of concrete increases
with the use of saturated saw dust. The inclusion of silica fume in internally cured
concrete reduced the workability and increases the porosity. However, the compressive
strength of the concrete and impermeability of concrete were improved with the use of
silica fume. The optimum saw dust content found in this study was 2.5%. It was found
that under curing with external water supply, the concrete with 2.5% of saturated saw
dust could achieve the target strength of 40MPa. It was found that the compressive
strength of 2.5% saw dust concrete was comparable to the control sample under dry
curing and 40°C oven condition. Despite the observed increase in porosity with the
percentage of saw dust, the permeability of the concrete with 2.5% saw dust was
significantly lower than the control mix under adverse curing condition with no external
curing water supply. As a conclusion, 2.5% of saturated saw dust can be applied as a
cost-effective internal curing material to produce a durable concrete where wet curing is
not applied.
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