Two basic formulations for expansive cement have been developed in the United States. One is designed to expand and compensate for the shrinkage which occurs in conventional portland cement concrete as it hardens. The product of this formulation is called "shrinkage compensated cement." The other is designed to create greater expansion in the concrete when it hardens, which will prestress the high tensile steel imbedded in the concrete. The product of this latter formulation is called "self-stressing cement." The former eliminates shrinkage cracks in concrete, while the latter produces concrete that prestresses itself. Utilization of the expansive cement that expands as the concrete cures is aimed at making self-stressing concrete members. After taking an initial set, the concrete expands, stretching reinforcing steel embedded in it. The tension imparted to reinforcing bars or strands precompresses the concrete member by reaction just as mechanical pretensioning and post-tensioning systems precompress conventional prestressed concrete. At present, self-stressing concrete, though still conservatively limited to a precompression of about 300 psi, should find applications in precast concrete pipe, precast architectural panels, highway pavement, sidewalks, and tunnel linings.