Authors: L. Leitão, R. Faria, L. Teixeira, M. Azenha

The paper presents an innovative experimental device, developed to characterize the viscoelastic behaviour of concrete when subjected to tensile stresses induced by restraints to drying shrinkage deformation. Two specimens of concrete with the same cross section are used, being submitted to the same drying conditions: one is made in plain concrete, whilst the other is reinforced with two steel rebars. The second specimen is installed on a reaction frame, being stretched in force or displacement control modes. The concrete of both specimens and the rebars are appropriately instrumented with strain gauges and thermometers, which allows separating the different components of concrete deformation, and thus to identify the viscoelastic one that is to be characterized. The device allows as well to determine the evolution of the elastic modulus of concrete, and remains operational even upon material cracking, features of remarkable interest for the testing operations.

L. Leitão¹, R. Faria¹, L. Teixeira¹, M. Azenha²
1 Faculdade de Engenharia da Universidade do Porto, Departamento de Engenharia Civil
2 ISISE, Universidade do Minho, Escola de Engenharia, Departamento de Engenharia Civil, Guimarães