A simple fracture mechanical interpretation of size effects in concrete fracture toughness tests

作者：Wallin Kim^*

来源：Engineering Fracture Mechanics, 2013, 99: 18-29.

DOI：10.1016/j.engfracmech.2013.01.018

• Concrete fracture
• Size effect
• Fracture toughness
• Quasibrittle materials
• K-R curve

Concrete is a so called quasibrittle material which, despite predominantly elastic material response, exhibits in tension loading a stable non-linear fracture response, when tested under displacement control. The reason for the non-linearity is the development of a fracture process zone, in front of the crack, due to micro-cracking and crack bridging. The effect of the fracture process zone is to make the specimen sense the crack as being longer than a(0) + Delta a The fracture process zone causes thus an effective increase in the crack driving force and apparent fracture resistance. Here, a novel LEFM based estimate of the effective stress intensity factor and the effective crack growth at maximum load in a fracture mechanics test is used to obtain a simple power law approximation of the effective K R curve. It is shown that it is applicable to the description of not only different size specimens, but also specimens with varying geometry. The method is based on a new theoretical estimate of the effective crack growth corresponding to maximum load.

• 出版日期2013-2