Suppressing Measure And Suppressing Mechanism Study On Alkali-Aggregate Reaction

Alkali aggregate reaction is one of three great disease which always affect important engineering safety and concrete durables, because the aggregate is reaction bulge with alkali(K, Na) inducing the concrete construction to crack destructively , even expired. Alkali—Silica Reaction ( Alkali—Silica Reaction, brief name ASR) is a widespread type. At present, domestic and international have carried a great deal of research on suppressing of ASR by mixing the addition ,and have accumulated a great deal of experiment data and experience. Through the first step experiment research indicated that the mixing addition can suppress the ASR to some extent, but there still have some great difference to the problem, because there exist some main differences of the quality of mixing addition and the experiment method of each researcher adoption. But the key is that the mechanism of mixing addition suppressing the ASR is still not quite clear, and the influence of mixing addition to the concrete strength etc. some key problem that always influence and guide the engineering practice didn't yet resolve.This text adopted the mortar-bar method and the mortar- prism method to carry on the experiment of suppressing in contrast. First, We used the DZ-4 and fly ash and the scoria to replace the cement with same quantity respectively, and modeled the piece with low activity, middle activity and high activity three series of aggregate , then conserved in 80 ℃ 1 mol/ L NaOH solution for 28 days, and tested the rate of expansion of the piece in the period of conserving. We used the aggregate ofQinghai-Tibet railroad------Xiaogangou, to examine the validity of suppressing theDZ-4 and the fly ash .Second, we adopted the DZ-4 and fly ash , the scoria to replace the sulfoaluminate cement in the mortar-bar method with same quantity respectively and experimented for testing the validity of suppressing, in the three series of activity aggregate and Xiaogangou ,then contrasted the result of experiment silicate cement and sulfur-aluminum cement, combineing the methed of microcosmic analysis, investigated to study the mechanism of the DZ-4 and fly ash and scoria suppressing ASR. Finally we did the experimentation of compressive strength and bending strength on mortar- prism, to analysis the influence of the two kinds of suppressing the measure on the strength of mortar or concrete.We did some experiment on the validity of suppressing and strength, and got validity and applicabilities of the two kinds of suppressing measure. Various mixing...