Evaluation and gradation of simultaneous damage in concrete affected by alkali-silica reaction and sulfate attack

Abstract

The concrete are considered as durable materials. Although, can be produced some interactions between the constituents inside the concrete and between the concretes with the environment that can induce the development of internal reactions. Some of these reactions development new products with higher volume than the original ones and promote the expansion and the cracks formation. Two of the more common internal degradation processes are alkali-silica reactions and sulfate attack. Usually these processes are considered separately, but in some cases these phenomenons shown together in the same concrete. On the other hand it is difficult the correct diagnosis of these degradation processes except by micro-structural analysis with electron microscopy and microanalysis techniques. But just the diagnosis it is not enough to know the state of one concrete structure. The experience in analysis and diagnosis of a lot of damage concrete structures permits to determine the grade of damage and assign a level of damage based on the microstructural studies. Finally, different microstructures, extension and localization of reactions products are used to define different levels of damage from 1 to 5 for concrete affected by alkali-silica reaction and sulfate attack.