掺合料的骨料碱活性抑制效能试验研究

Test and Study of Inhibition Efficiency of Alkali Activity of Admixture Aggregate

根据某大型水电工程在设计施工阶段所做的大量试验研究,全面阐述了目前混凝土中常用的几种掺合料的抑制碱骨料反应的效能情况、掺量变化等,为该工程建设用掺合料的优选提供科学依据。试验研究发现,Ⅰ、Ⅱ级粉煤灰及TF料3种掺合料碱骨料反应抑制效能均较好,膨胀率降低效果显著,评定为抑制混凝土碱—骨料反应有效,三者之间无显著优劣顺序。对于TL料、PL料,在不同掺量下试件的膨胀率较不掺掺合料基本有所降低,但抑制效果总体均较差。总体来讲,粉煤灰目前仍然是最有效的抑制碱—骨料反应的掺合料。

The paper explains the overall situation of the inhibition efficiency of alkali aggregate reaction and the content variation of several admixtures that are much used in concrete at the present time according to a large quantity of test and study conducted in the design and construction stages of a large hydropower project, which provided scientific basis for optimum selection of admixtures in construction of the project. The test indicates that the inhibition efficiency of alkali aggregate reaction of such 3 admixtures as Grade I and Grade II fly ash and TF material is all better and their expansion ratio reduced significantly, which are all rated as effective inhibition of concrete alkali aggregate reaction without significant discrimination between good and bad among them. As compared with the concrete aggregate without admixture, the expansion ratio of the test samples of TL and PL materials with different admixture content is somewhat reduced but their inhibition efficiency is poor as a whole. In the general, fly ash is the most effective admixture to inhibit alkali aggregate reaction at present.