Investigation of fracture properties and size effects of mass concrete using wedge splitting tests on large specimens

This work presents experimental results of fracture tests on very large concrete specimens of mass concrete mixture with a maximum aggregate size of 100 mm. Wedge splitting tests were performed on very large concrete specimens and on moderate-size specimens sawn from large concrete blocks to investigate both size and temperature effects. The digital image correlation (DIC) technique allowed to assess the fracture parameters of these specimens, including the critical crack opening displacement and crack growth length at the peak. These parameters were compared to theoretical computed parameters based on linear elastic fracture mechanics or LEFM theory. Cyclic splitting tests were additionally performed on very large and moderate-size concrete specimens. Interpretation of the results of these cyclic tests via DIC enabled to formulate important conclusions regarding the evolution of the fracture process zone length and critical opening displacement during the tests and to validate the hypotheses associated with the recently developed disturbed fracture process zone theory in terms of the size effect on the fracture energy.