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CONCRETE TECHNOLOGYwww.cpi-worldwide.com CPI %u2013 Concrete Plant International %u2013 1 | 2026 47Test resultsDamage localization marks the point at which the validity of a stress-strain relationship (%u03c3-%u03b5) ends. Up to this point, a uniform deformation can be assumed. Once a dominant crack forms, deformation becomes concentrated almost exclusively in this crack region, meaning that the deformation energy can no longer be assumed to be homogeneously distributed between the load application points. The following response parameters are defined:%u2022 The test load at first cracking (Fel).%u2022 The maximum load and the corresponding deflection (Fmax,%u03b4max).%u2022 The localization load and the corresponding deflection (Floc,%u03b4loc).This is the load at which the crack-bridging effect of the fibres in a single crack plane begins to be exhausted. Additional cracks may form thereafter, but their influence is negligible.%u2022 The total deformation and load at the end of multiple cracking (%u03b4mult, Fmult).This corresponds to the absence of load drops that are characteristic of the formation of new cracks [16].%u2022 The post-localization knee point (%u03b4post, Fpost).This represents the transition between the descending branch and the approximately asymptotic region after localization.%u2022 The post-localization zero point (%u03b40-post, 0).%u2022 The pre-localization knee point (%u03b4pre, Fpre).This marks the transition from the first post-elastic region of the ascending branch to the second region with a reduced slope prior to localization.The behaviour observed in the four-point bending test can be divided into four phases (Fig. 3).Fig. 3: Load%u2013deflection diagram with strain-controlled and crack-opening%u2013controlled regions, based on [17, 18].