An experimental study of bridge deck cracking using type K-cement

This paper experimentally investigates the effects of drying shrinkage on bridge decks, its relation to bridge deck cracking, and possible methods for abating its effects. The experiments were performed through the use of two 7 ft. × 10 ft. experimental concrete bridge bays, each instrumented with strain and temperature gages throughout the deck and girders. The data was collected in a six months’ time frame. The first deck was poured with a control concrete mixture used currently in Illinois. The second deck was poured with type K expansive cement concrete, which could battle the effects of shrinkage. For both decks, the results indicated a compressive strain throughout the rebar and along the top surface of the concrete, except for the locations where cracks are found (at these locations the strain slopes upward into tension). The strain in the type K deck, though, was notably less than that in the control deck and the onset of cracking was delayed by three weeks, giving the indication of an improvement over the current mix design.