Highway Pavement Materials and Design 223
Longitudinal joints may also be required to counteract the effects of warping
along the length of the slab. They are broadly similar in layout to transverse
warping joints.
7.7.3 Reinforcement
Reinforcement can be in the form of a prefabricated mesh or a bar-mat. The
function of the reinforcement is to limit the extent of surface cracking in order
to maintain the particle interlock within the aggregate.
In order to maximise its bond with the concrete within the slab, care must be
taken to ensure that the steel is cleaned thoroughly before use. Because the
purpose of the reinforcement is to minimise cracking, it should be placed near
the upper surface of the pavement slab. A cover of approximately 60 mm is
usually required, though this may be reduced slightly for thinner slabs. It is nor-
SLAB SLAB
Seal
Crack inducer
SUBBASE
Tie bar
Figure 7.17Warping joint detail.
SLAB SLAB
Reinforcement overlapping
by 600 mm minimum
SUBBASE
Tie bar
Figure 7.18Construction joint detail.
