Reaction between certain Jordanian rock-aggregate and cement in Roller Compacted Concrete (RCC) dams

One of the causes of concrete deterioration that has received considerable attention in recent years is the alkali aggregate reaction (AAR). Alkali aggregate reaction affects adversely concrete durability causing abnormal expansion, cracking, and loss of strength. This paper describes a series of study conducted with the aim of evaluation the susceptibility of the materials of RCC dams in exhibit expansion due to AAR, results obtained by using current characterization techniques (The Quick Chemical Method-ASTM C 289, Mortar Bar Method-ASTM C 227 and Accelerated Mortar Bar Method-ASTM C 1260), were used to study the ability of different types of Jordanian aggregate to cause alkali aggregate reaction, results indicate that the main types of Jordanian aggregate could be considered as innocuous aggregate, with no expected expansion results from alkali aggregate reaction, except some types such as opal and some types of sands and cherts. As a case of study the susceptibility of the Mujib RCC dam located in Jordan was examined, after studying the main factors contributed to the alkali aggregate reaction, the results obtained eliminated the idea of ability of the RCC material proportion to cause alkali aggregate reaction.