Abstract
Influence of microstructural changes in high strength concrete on toughening mechanism is studied. Load-displacement curves of notched beams of various types of concrete are analyzed by means of an inverse analysis technique to obtain the tension softening diagrams. Parameters of the bilinear tension softening diagram are discussed in relation to dynamic Young's modulus, compressive strength, tensile strength and porosity. A brittleness index was also proposed, which is defined as a function of fracture energy, tensile strength and Young's modulus. These results are useful to determine the tension softening diagram of concrete on the basis of general standard test results.
