ABSTRACT
Curling is the warping of a concrete slab so its edges are left higher than its centre. The main cause is differential drying shrinkage through the thickness of the floor. If a concrete floor dries from the top - and groundsupported floors almost always do - the top shrinks faster than the bottom. This differential shrinkage warps the slab, making it concave upward (Figure 14.1). Thermal contraction can also curl a slab, but it plays a much smaller role than drying shrinkage-at least on interior floor slabs.
