._,....,U'V'•JA of Civil Engineering, State University of Campinas, Brazil Bittencourt Laboratory Computational Mechanics, Polytechnic School, Brazil " .. .,....,....a.rt•• .. ,,,.., involved in the Three Point Bending Test of are reviewed. Special attention is given to the reloading procedures involved…
._,....,U'V'•JA of Civil Engineering, State University of Campinas, Brazil Bittencourt Laboratory Computational Mechanics, Polytechnic School, Brazil " .. .,....,....a.rt•• .. ,,,.., involved in the Three Point Bending Test of are reviewed. Special attention is given to the reloading procedures involved in the Level II vertical drop of the load level, at the peak load of l""'AM•c<Tonr CMOD condition has been observed. This variation with time, tending loop in which the load level is response, was understood initially as a mamt~mance of the CMOD at the level where re1axEmon process. The load decline may cohesive interface is opening with a ,..,... • .,,,"""'"'"""tractions. It was observed that each descendant one practically at the interception points form a new f'n1!"1!"""'~nr'l.Ylrll!YIO' to the maximum loads of each cycle. toughness, level II three-point 1 Int:rod uction fracture toughness of concrete and mortar is usually determined through Level I and Level II tests. As it is well known, three point bending Level I tests require basically the maximum load, P max' the Young Modulus, E, resultant or not from the fracture test, accompanied by the load line deflection at the maximum load, bmau or the initial and the unload compliances, C1 and Cu. These models are known as the Effective Crack Model by Karihaloo and Nalathambi (1989) and the Two Parameters Crack Model, by Jenq and Shah (1985), respectively.