الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Composite action of any reinforced concrete member is only possible if only sufficient bond
strength exists between steel reinforcing bar and concrete, which can adequately transfer shear
stress between them. Bond strength is a function of compressive strength of concrete. In order
to investigate the effect of embedment length, concrete cover, bar diameter, pre-flexural crack
length, and compressive strength up to 90MPa on both bond strength, and slippage an
experimental program was carried out. A new trend of proof bond strength was proposed.
The stages of the research can be summarized as following:
1. Establish an optimum mix proportions in order to produce concrete with high strength and
good workability.
2. Compressive strength tests were carried out for all mixes.
3. Tensile pullout bond tests were carried out to evaluate the bond strength.
4. The effect of concrete cover, concrete compressive strength, bar diameter, flexure cracks,
and embedment length was determined.
5. An experimental bond strength was compared with ultimate bond strengths from different
equations (Darwin et al (I), Orangun et al (2), Esthani and rangan(3), Muhammad N.S. Hadi(4),
Zuo and Darwin(2000p), BS-811O-1997(Table(3-26)i6), ACI 408Eq(I-5) (7), and Egyptian
code (8).
6. A new trend of proof bond strength was proposed.
7. Proof bond strength and development length equations were proposed.
The test results were tabulated and plotted through figures. Detailed discussions for results
were considered.
The study yields many conclusions for which,
1. The experimental results of the bond strength were close to ACI results for concretes of
compressive strength of 30 to 50MPa, and they were close to Zuo and Darwin (5) results for
concretes of compressive strength of 70 to 90MPa ..
2. Idealized bond stress- slip relationship and proof bond strength is proposed.
3. Equation (4-12) to calculate the proof bond strength was proposed.
4. The Egyptian code equation (4-8) to calculate the bond strength, considerably under-estimates
the bond strength.
5. Equation (4-14) to calculate the required development length was proposed