This research examines the effect of lateral pressures
on the bond characteristics of both plain and deformed reinforcing
bars in lightweight aggregate (Lytag) concrete. Two common bond
tests, the cube pull-out and the semi-beam test, were modified in
order that lateral pressures could be applied to the bond specimens.
The major variables studied were the magnitude of the lateral pressure,
the bar diameter, the length of embedment and the concrete strength.
The results of over 200 bond tests show that for round
bars the application of a lateral pressure close to the cube-strength
of the concrete can result in an increase in pull-out load of as
much as 260% and that for similar sized deformed bars the
corresponding increase is about 75%. The different bond mechanisms
for round and deformed bars were highlighted by the failure modes
of the bond specimens and this difference in behaviour is reflected
in the theoretical work by a frictional bond strength criterion for
round bars and a splitting or shearing criterion for deformed bars.
As part of the experimental work a reinforcing bar was
fully strain-gauged, enabling the strain distribution along the bar
to be monitored for various combinations of lateral pressure and pull-out
loads. The bond stress was found to be uniformly distributed
along the bar for pull-out loads greater than about half the ultimate
and the strain distribution relatively unaffected by increasing
Finally, to test the conclusions from the bond pull-out
tests in a practical situation, a total of sixty-four lightweight
concrete deep beams, with varying anchorage lengths, bearing block
sizes and web reinforcement were tested. The results of these
tests confirm that the high bearing stresses that occur at the
supports of deep beams do have significant positive effects on the
anchorage bond that can be developed. A method is proposed to take
into account the enhanced bond strengths that occur over the
supports of deep beams with span/depth ratios of less than 2.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.