A PARAMETRIC MODEL DISCUSSION FOR THE CONCRETE EXPANSION DUE TO AAR

摘要

Concrete strength and durability reduction are two of the major consequences of the long-term chemical reaction evolution between the cement alkali and certain minerals from the aggregate. This reaction is known as alkali-aggregate reaction. It provokes a heterogeneous expansion of the concrete causing geometry changes and eventually, loss of functionality. In concrete dams these effects can be very costly and the development of numerical tools to diagnose and correct the problem should be welcome. In this work, a parametric model to simulate concrete expansion is proposed, which uses the main AAR influence factors to form its basis. The employed methodology consists on obtaining the spatial distribution of these influence factors, parameters normalization and the use of a constitutive relationship to retrieve the expansive AAR rate of deformation. An optimization technique is also employed to adjust the computed parameters to existing field measurements. The methodology was developed in a commercial finite element package and tested in a for simple three-dimensional finite element model.