A study of Alkali Silica Reactivity of Some of Aggregates Used in Concrete in the West of Iran

The aggregates as a prominent part of concrete mixture have significant impact on durability and strength of concrete. One of the most important problems attributed to some part of aggregates in Iran are reported to possibly deleterious alkali silica reaction between the hydroxyl ions (OH−) in the pore solution and reactive silica in the aggregate over the time. So, investigation of alkali-silica reaction potential for aggregate in this area is so invaluable because of high consumption of these suspicious materials in the construction of varied hydraulic structures.In present study, alkali silica reactivity of aggregate in a number of mines in West of Iran including Zanjan, Kermanshah and Kordestan province has been investigated comprehensively. In this regard, in order to evaluate alkali silica reactivity of aggregates, petrography examination of aggregate according to ASTM C295, alkali silica reactivity mortar bar testing according to ASTM C1260 and determination of length change of concrete due to alkali silica reaction according to ASTM C1293 was used. Based on results obtained in present study, it was concluded that alkali silica reactivity was observed at a number of aggregates placed in every three studied province and in order to using of these aggregate at concrete structures exposed to water, preventive action including using low alkali cement or pozzolan could be useful.