Experimental Study of Shear Fracture and Aggregate Interlock in CementbasedComposites

摘要

In the present paper the results of an exploratory study with the recentlydeveloped biaxial tension/shear apparatus of the Stevin Laboratory of Delft University of Technology are presented. The apparatus is unique in the sense that square double-edge-notched concrete plates up to a size of 200 x 200 mm can be loaded in any combination of tension and shear in displacement control. The two loading axes are completely independent of one another. In the paper, both results of experiments on plain concrete and on slurry infiltrated fiber concrete (SIFCON) are presented. The experiments can be divided into two main categories. In the first catagory, aggregate interlock has been studied for narrow cracks (between 10 and 400 micrometers) that can still transmit tensile loads normal to the crack plane. In the second catagory of experiments specimens were sheared off without precracking them (mode II), but in a few cases with simultaneous tensile loading (mixed mode I and II). The shear tests on specimens containing narrow cracks revealed an abundance of secondary cracking. The exact boundary conditions were very important here. Tests have been carried out with either zero