CONCRETE STRENGTH AND BOND BEHAVIOUR IN CHEMICALLY AGGRESSIVE ENVIRONMENTS
CONCRETE STRENGTH AND BOND BEHAVIOUR IN CHEMICALLY AGGRESSIVE ENVIRONMENTS
No Thumbnail Available
Date
1996-06
Authors
JOSEPH AKPAN, ANTHONY
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The results of pullout and compression tests of concrete subjected to a simulated aggressive
chemical environment is presented. About one hundred and tour pull out test specimens and
one hundred and fourteen cubes were tested for ultimate local bond strength after curing for
one hundred and eight days in different aggressive media.
Two of the simulated environments were acid based while the third was caustic. The cubes
cured in the acid based environment namely, Sulphuric and Hydrochloric acids showed a
remarkable strength loss for the grade 30 and 40 concrete used. The caustic medium,
Sodium Chloride solution did not show any convincing strength loss.
A natural occurring material, Rubber Latex ( Poly 1- 4 Isoprene ) for coating small
diameter bars in "light" structures was examined. With an appreciable Bond Ratio range of
0.97 to 1.05 the material is found acceptable as a coating medium for concrete reinforcement
bars.
The simulated aggresive media had volume fractions restricted to 2 percent for the Pullout
test and 3 percent for the Compressive Strength Test. It was observed that for Local Bond
requirements to be controlled, higher grade of concrete may be necessary depending on the
nature of the aggressive environment and the bar diameter. It was also observed that the
limiting volume fraction for maximum ultimate bond stress is a function of the bar size and
the concrete grade. Thus for grade 30 concrete, the limiting value is between the range of
(0.57 to 0.74) percent for sulphuric acid simulated medium and (0.95 to 1.0) percent for
hydrochloric acid simulated medium. That of grade 40 concrete in a sulphuric and
hydrochloric acids simulated media are within the range of (0.95 to 1.45) percent and (1.10
to 1.20) percent respectively.
Description
A Dissertation presented for the award of the doctor of Philosophy (Ph.D.)
degree in Structural Engineering.
Department of Civil Engineering
Ahmadu Bello University
Zaria, NIGERIA
June, 1996
Keywords
CONCRETE,, STRENGTH,, BOND BEHAVIOUR,, CHEMICALLY,, AGGRESSIVE,, ENVIRONMENTS.