Mode I Fracture Toughness Determination of Rock and Concrete via Pull-Off Test.

In this paper, the Pull-Off Test (POT) was analyzed as a method for determining the mode I fracture toughness (KIc) of rock and concrete. POT is submitted to tensile load (which causes a simpler stress state than tests submitted to bending and compression load) and its execution is easy, replicable and can be performed in laboratory and in situ (being its great advantage). A ratio between the dimensions of the POT was proposed to meet the Linear Elastic Fracture Mechanics requirements and the POT literature recommendations. Parametric studies were performed using numerical analysis and it was concluded that the POT is suitable for KIc testing, since mode I prevails in the test, and an equation was proposed for determining KIc in homogeneous rock and concrete (micro-concrete and mortar). A practical example of the method application was provided and KIc was determined for some homogeneous rocks. A similar result was achieved between POT and Semi-Circular Bending test. Highlights: The Pull-Off Test was analyzed as a method for determining the mode I fracture toughness of rock and concrete. The execution of the Pull-Off Test is easy, replicable and can be performed in laboratory and in situ. A ratio between the dimensions of the Pull-Off Test was proposed. The Pull-Off Test is suitable for mode I fracture toughness testing, since mode I prevails in the test. An equation was proposed for determining the mode I fracture toughness via Pull-Off Test of homogeneous rocks and concretes (micro-concrete and mortar). [ABSTRACT FROM AUTHOR]