Shrinkage-compensating cement concrete can complement the benefits of post-tensioning by reducing the normal amount of loss of prestress, reducing flexural cracking and improving durability. Comparative designs of a 6-story structure, 10 bays long along the axis of the prestressing force, show significant differences between shrinkage-compensating and conventional Portland cement concretes.
Building floors made with shrinkage-compensating cement concrete induced 75 percent less moment on interior columns than the 542 foot-kips induced by floors made with Portland cement concrete. For exterior floors the reduction was 66 percent below the 455 foot-kips of Portland cement concrete floors. These resulted in savings in reinforcing steel of 29 percent for interior columns and 47 percent for exterior columns.
In addition to such applications as slabs in multibay multistory structures, parking decks, slabs on expansive soils, slabs below the water table, and concrete roofs, the combination of shrinkage-compensating cement concrete with post-tensioning has also found use in waste-water treatment plants. In general these uses have saved money by reducing the amount of post-tensioning steel needed, and sometimes by making it possible to reduce or eliminate such cumbersome details as slip joints, wrapped dowels and the extra steel that might be needed to control cracking in vulnerable areas.