Cracks have often occurred in the conventional concrete pavements (10 cm thickness) on pier slabs. The purpose of this study is to find out the cause of the cracking and its control methods.
　Four kinds of concrete test pavements are made on the concrete pier slabs of Chiba Port and various items such as temperature, strain and displacement are observed in these test pavements for one year.
　From these results, the following conclusions are made clear.
(1) Among the thermal stresses of conventional concrete pavements on pier slabs, end restraint stress is fairly large in spite of small internal and restrained warping stresses.
(2) The cause of the cracking in the concrete pavement slabs is excessive tensile stress generated by reason that the shrinkage of concrete pavement due to drying and temperature descent is restrained by the pier concrete slab.
(3) Two methods to control the shrinkage cracking are proved actually. One is to spread plastic sheet on pier slabs and another is to use adequate expansive cement concrete for pavement slabs.