Comprehensive concrete fracture tests: Size effects of Types 1 & 2, crack length effect and postpeak

摘要

The comprehensive fracture tests of notched and unnotched beams presented in the pre-ceding paper are evaluated to clarify the size effects and fracture energy dissipation. Thetest results for beams with notches of various lengths agree closely with Bazant's Type 2size effect law and yield the value of the initial fracture energy G_f Since nearly completepost-peak softening load-displacement curves have been obtained, the total energy dissi-pation by fracture can be accurately evaluated and used to determine the RILEM total frac-ture energy G_F For the present concrete, G_F/G_f ≈ 2. The transition between the Type 1 and 2size effects are determined and is found to be very different from that assumed m Hu andDuan's boundary effect model. Determination of a universal size effect law fitting the beamstrengths for all the sizes and all notch depths is relegated to a subsequent paper.