Investigation of the chemical reactivity of concrete in some large dams of Iran

The chemical reactivity of concrete is one of the most important factors in long term damage and destruction of concrete structures. In this study, the chemical reactivity of some large concrete structures in the south of Iran has been investigated. For this purpose, the concrete sections of six large dams have been studied during field visits and taking more than 16 concrete samples and sediment of concrete surface. The investigated structures include Dez, Balaroud, Godarlandar (Masjed-Soleyman), Gotvand Uleya, Karkheh, and Jarreh (Ramhormoz) dams. Using field investigations, determination of Damage Rating Index (DRI), and chemical composition of the surface sediments and leachate of the concrete, the chemical reactivity of the concrete and its degradation have been investigated. The method of DRI is the petrographic method to quantify the state of damage of concrete by the alkali-aggregate reaction. The results of DRI and field studies show that except for Dez dam, all concrete structures under study have alkali-aggregate reaction, but it is not yet developed enough to cause serious damage to its concrete. The results of the XRD whit emphasis field evidence indicate the presence of external sulfate attacks in the studied parts of Jarreh and Balaroud dams.