Title: Determination of Crack Resistance Curves of Cementitious Materials from Measurements of a Wedge Splitting Test
Author(s): K. A. Rieder
Publication: Symposium Paper
Appears on pages(s): 207-228
Keywords: concrete; crack growth resistance; fiber reinforced con-crete;
fracture test; R-curve; wedge splitting test
The wedge splitting test method was used for determining the crack growth resistance curve (R-curve) behavior of cementitious materials. Two things are needed to calculate a crack resistance curve: 1) A sufficiently large fracture surface area to obtain size-independent fracture values; 2) Stable crack propagation until complete separation of the specimen. It is very difficult to fulfill both requirements simultaneously because relatively high testing loads are necessary to fracture large specimens, which often leads to unstable crack propagation. A wedge splitting test has been shown to achieve stable crack propagation for suitable specimen sizes for mode I failure. A splitting load with a slim wedge is used to develop a load-displacement curve for the stable cracking of cubic specimens. A method was established using only the load-displacement curve for the cal-culation of the crack resistance curve. The testing procedure as well as the method to cal-culate the crack resistance curve is described. The results are shown on five examples of plain concrete and fiber reinforced concrete. The fracture mechanical behavior of plain concrete and fiber reinforced concrete was analyzed using the methods discussed.