Experimental Study on the Alkali-activity of Granite Aggregate in Mianhuatan Hydroelectric Station

摘要

The concrete aggregates are made of granite in Mianhuatan hydroelectric station. The granite is mainly composed of feldspar, quartz, biotite and few hornblende or chlorite, etc. The aggregates have been determined on alkali reactivity potential by petrography method, chemical method, rapid method, accelerated mortar bar method and mortar bar method. As a result, there are some micro particle quartz in the flecky granite and the broken granite, the granites are potential alkali reactivity aggregates. If concrete aggregates are made of granite, alkali reactivity of the granite must be concerned. In order to insure safety of darn, the alkali content of cement must be controlled strictly, or the addition of fly ash is at least 20%.