Study On The Inhibition Of Alkali Aggregate Reaction With High Performance Concrete

Concrete alkali aggregate reaction is one of the important factors affecting the durability of concrete, this paper studies the effect of the content of admixture and water cement ratio on the expansion rate and the ability to restrain the alkali aggregate reaction. The main conclusions are as follows:(1)Determined by petrographic method test, Urumqi area concrete with aggregate of 67% for tuff, accelerated mortar bar method and prism method measured expansion rate all exceed regulatory requirements, can determine tuff aggregate alkali activity.(2)The main factors that restrain the alkali aggregate reaction are the water cement ratio, the content of the mixture, and the curing age by the method of rapid mortar bar test and prism test. The expansion rate of concrete specimens in the same age, with the increase of water binder ratio and the content of the admixture, decreased with the increase of the curing age. From a mix of point of view, in addition to considering the alkali content, on the one hand, through the water to binder ratio decreased with the increase of concrete compaction degree, reduce the moisture in concrete mobile and alkali ion movement; on the other hand, adding mineral admixture in the synthetic material which belongs to the active mixing material, ingredient and cement clinker hydration product of calcium hydroxide and water in alkali to react and generate water rigid materials. The reason why the mixed material can restrain the alkali aggregate reaction is because it absorbs the alkali in cement or concrete, reduces the alkali content in concrete, can effectively inhibit the alkali aggregate reaction. Secondly, the admixture can replace the amount of cement, cement dosage is less, the content of the alkali content of concrete will be reduced accordingly, it is reduced the alkali in concrete.(3)Through the experimental study found a phenomenon, try adding admixture prism method 52 weeks of age respectively in expansion rate of water to binder ratio had less influence, 0.44 water glue competition piece is expanding at a slower rate than low water binder ratio of expansion rate. In accordance with the law of the strength of high performance concrete analysis, 0.44 water to binder ratio tried a compacting degree far below 0.40 following water binder ratio than the specimen, internal porosity is much larger than, extra low water cement proportion. Therefore, this phenomenon may should flood gum competition in pore offset part of the aggregate of the interface occur alkali aggregate expansion stress, caused 0.44 water binder ratio a no significant expansion rate of growth, hope in the future study can be verified.