Experimental Investigation of Horizontal Crack Formation in Frost-damaged Concrete Cylindrical Specimens

抄録

Frost-induced deterioration remains a critical factor limiting the durability of reinforced concrete (RC) bridge deck slabs in cold regions. Repeated freeze-thaw (FT) cycles lead to the formation of horizontally layered cracks in RC bridge deck slabs, eventually leading to the fall-off of concrete and the cave-in of pavement. To elucidate the mechanism responsible for such damage, a two-stage experimental investigation was conducted using a thermoelectric cooler (TEC)-based system on concrete cylindrical specimens. In the first stage, specimens were subjected to accelerated FT cycles to simulate frost deterioration possible in RC bridge deck slabs. The extent of deterioration was quantified through ultrasound velocity measurements. Physical properties exhibited progressive degradation with an increase in the number of FT cycles. For example, after 25 FT cycles, the oven-dry and saturated weights decreased by 3.2% and 2.3%, respectively. Additionally, X-ray computed tomography (CT) analysis was employed to analyze the crack network and cracking volume. In the second stage, steady thermal conditions were imposed, with one face of the specimen undergoing freezing and the opposite face thawing in the presence of water. Horizontal cracking associated with ice lens growth was observed in all specimens that had been pre-damaged by FT cycling. The results imply a possibility of ice lens formation in inducing horizontal cracking in frost-damaged RC bridge deck slabs.