Properties of oil saturated concrete.

Large concrete structures are being built for the
production, storage and transportation of oil. The effects
of crude oil on the properties of concrete are not well known
and little data is available in the published literature.
The present investigation is divided into three parts:
1) A study of the mechanical properties of oil saturated
hardened cement paste, mortar and concrete.
2) A study of the effect of absorbed oil on the average
bond stress, and the bond stress distribution between
reinforcing bar and concrete.
3) A study of the changes in the dynamic modulus and
logarithmic decrement of concrete soaked in oil for
different periods.
All the specimens were oven dried to increase the
permeability of concrete to oil and to increase the degree of
oil saturation. The results were compared with those of
similar specimens soaked in water or sealed in polythene
bags as control specimens.
The mechanical properties. of HCPs, mortar, and concrete
studied here were adversely affected by oil saturation.
The compressive strength and elastic modulus were reduced by
amounts depending on the amount of oil absorbed. The tensile
strength was also reduced due to soaking in oil but the
reduction was less than that of the companion specimens sealed
as a reference. It appears that the oil mainly affects the
aggregate-cement bond strength.
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The average bond strength between steel and concrete,
for both plain and deformed bars, decreases with an increase
in the amount of absorbed oil. The reduction. for the plain
bar was between 1.8-2.3 times greater than that for the
deformed bar. The study of the bond stress distribution
showed that at the maximum applied-load, the local bond
stress at the embedded end of the oil saturated specimens was
about six times greater than that at the loaded end.
The dynamic modulus of elasticity increased by 12-14%
after soaking the concrete in oil for 580 days compared to
the oven dried specimens. The increase w~s about 37% less
than that of similar water soaked specimens. The studies
of logarithmic decrement indicate that the loss of moisture
is the most important factor influencing damping capacity.