With the great strides which have been made in concrete technology and structural design, the problem of pavement cracking is no longer the serious consideration it once was. But, nevertheless, concrete pavements still develop cracks under certain conditions and awareness of this fact, coupled with an understanding of the various factors involved, is an essential part of any good concrete man's bag of tricks. Defects can be found revolving around two main categories: those involving wheel loads and those that do not. Under those involving wheel loads, one problem can be corner breaks. If this is indeed the problem, the legs on both sides will generally be 2 to 4 feet long. Another problem is slab and end breaks. These are caused by loads applied after there has been a loss of subgrade support as a result of consolidation or pumping action. Other defects which fall into this category or faulting of slab end and pumping. Plastic shrinkage cracks are an example of a kind of defect which does not involve wheel load. These occur when wind velocity, low humidity, and high air temperature cause water to evaporate form the concrete surface more rapidly than it is replaced by bleeding. Spalls are unsightly defects that usually because of poor construction practices. Transverse cracks, though, are usually caused by frozen dowels. Other examples of no wheel load defects are longitudinal cracks and herringbone cracks.