When concrete elements are restrained by base friction or lateral stiffness of support elements, cumulative strains arising from shrinkage and temperature changes can cause cracking. It is possible to provide contraction joints that minimize cracking, yet do not interfere significantly with construction schedules. By detailing contraction joints, the engineer can place cracks where they have minimal effect on structural performance; productivity during construction of elevated floors can be improved; and large placements can be avoided

After 100 years, the American Concrete Institute leads the world in concrete technology, affording a sound basis in published guides for high-performance industrial concrete floors meeting the highest serviceability standards. In discussing high-performance concrete, the author describes a prototype specification. The hallmarks of this specification are the optimization of aggregate gradations and the minimization of water, embodied in the principle that exposed interior slab-on-ground concrete is in a special high-performance category, distinguished by lowest achievable shrinkage characteristics and highest serviceability standards—distinct from other usages where strength alone governs