Nonlinear creep, Poisson's ratio, and creep-damage interaction of concrete in compression

The results of a set of short-term uniaxial creep tests at low, medium, high, and very high stress levels are presented. Creep Poisson's ratio evolution with time, nonlinear creep strain amplification, damage growth, and creep-damage interaction of concrete in compression are investigated. The electronic speckle pattern interferometry (ESP1) technique has been used to measure transverse strain also when, at high stress levels, cracks grow and propagate in concrete specimens. Under high stresses, creep Poisson 's ratio shows variation in lime, associated with damage evolution. Moreover, tests showed that for medium to high stress levels, nonlinear creep strain amplification occurs, even if not accompanied by significant concrete damage.