According to GBJ82-85 test method for frost resistance of concrete, four-point bendingtests were used to examine the effects of water-cement ratio and air-entraining agent onfracture toughness, fracture energy and dynamic elastic modulus of concrete subjected to 300rapid freeze-thaw cycles. The microstructure of the concrete was also analyzed. The resultsshow that with the increase of the number of freeze-thaw cycles, the fracture toughness ofconcrete, and the loss of fracture energy as well as the loss of relative dynamic elasticmodulus showed a downward trend. The higher water-cement ratio, the severer the damage ofconcrete as the number of freeze-thaw cycles increased. Air-entraining agent can significantlyreduce the damage of concrete structure due to freeze-thaw cycles. The loss of fracture energyand the loss of relative dynamic elastic modulus kept a good linear relationship.
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