ABSTRACT
Abstract To analyse the effects of chemical damage on the stiffness and strength of a reinforced concrete member, it is necessary to simulate both the stresses induced during the reaction and the changed material properties. Alkali aggregate reaction (AAR) is an example of chemical damage which causes expansion, that is both time and stress related. The paper describes results of tests to determine expansion-stress relationships and constitutive equations for a laboratory concrete used in a number of centres. It also discusses the influence of size effects, shear tests and compares the results of bond tests conducted using the special concrete and specimens cut from an in-situ structure. Keywords: Concrete deterioration, alkali aggegate reaction, size effects, shear trength, bond strength
1 Material properties
To conduct an analysis to determine the internal stress distributions caused by restraint to AAR, it is necessary to use constitutive equations for the deteriorated concrete. Such analyses were necessary to explain experimental data from laboratory cast specimens using a special concrete, with added alkalis, conditioned under hot water and designed by the BRE [1]. As AAR is stress dependent, constitutive equations for different degrees of expansion are required.
