Experimental Study on the Influence of Humidity on Double-K Fracture Toughness and Fracture Energy of Concrete under Water Environment

Saturated concrete is significantly different from dry in fracture mechanical properties. Using the wedge-splitting tensile method to research rule of change moisture content, double-K toughness and energy three strength grades (C20, C30, C40) immersed a free water environment for 0 h, 2 5 24 120 h were studied order provide support safety evaluation structures environment. The initial cracking C20, C40 saturated state were, respectively, 29.6%, 23.2%, 33.4% lower than that state. unstable 22.7%, 23.9% 33.8% are only 71.99%, 70.29%, 66.11% state, respectively. all show linear, decreasing trend with an increase content. Before crack initiation, measured P–CMOD curve had obvious linear elastic stage, stable expansion stage. critical opening displacement gradually decreases content; deformation capacity shown decrease. humidity should be fully considered when evaluating properties concrete.