Short- and long-term restrained shrinkage cracking of fiber reinforced concrete composite metal decks: an experimental study

Abstract

In this experimental investigation, synthetic macro fibers and conventional welded wire mesh (WWM) were used in composite slabs to investigate their effectiveness in controlling load and shrinkage induced cracking. Two types of experiments were conducted: restrained shrinkage tests and large-scale loaded composite continuous slabs. Both short and long-term performance was investigated. Shrinkage and load-induced crack widths, and mid-span deflection were measured. Different dosage rates of the synthetic macro fiber were used and compared with conventional WWM. The minimum dosage of fibers and conventional WWM specified by ANSI-SDI-C2011 to control cracking in composite slabs were particularly examined. The restrained shrinkage test provides data on crack width caused by shrinkage, while the large-scale continuous slab was intended to monitor the mid-span deflection and crack width across the middle support caused by the load, shrinkage and creep. The results show that both minimum WWM and fiber dosage have comparable performance in controlling the crack width. Long term monitoring indicate that the crack width for both reinforcing systems increased with loading time and stabilized thereafter. Finally, the mid-span deflections for both tested reinforcing systems indicate that the fibers have comparable performance to WWM both short- and long-term. The results of the long-term deflection and crack width relative to the short-term values show a significant and comparable time dependent increase in these properties for both reinforcing systems. Furthermore, no fracture in the crack bridging fibers was observed under sustained load. These results indicate that creep of composite slabs for both reinforcing systems is not entirely related to the type of reinforcing material bridging the crack.