Experimental Study of the Effect of RCC Specimen Size and Crack Depth Ratio on Double-K Fracture Parameters

摘要

When the height of roller compacted concrete (RCC) specimen is less than 400 mm, the specimen size and crack depth ratio will affect the double-K fracture parameters. In this paper, two groups of RCC specimens with different specimen size and crack depth ratio were investigated and the wedge splitting method was employed. Double-K fracture parameters were calculated employing the double-K fracture theory of concrete. It is indicated that when the crack depth ratio, a, increased from 0.4 to 0.6, the unstable fracture toughness, K_(IC)~(un), increases, while the initial fracture toughness, K_(IC)~(ini), decreases. The crack depth ratio, a, has a continuous effect on K_(IC)~(ini), however the effect on K_(IC)~(un) decreases with the increase of a. When the height of the specimen, h, is less than 300 mm, the effect of specimen size on K_(IC)~(un) is significant, but it decreases when h is greater than 300 mm and less than 500 mm.