Study On Influence And Inhibitory Role Of Compound Admixture On Alkali-aggregate Reaction

Alkali-Aggregate reaction(AAR) is one of the main reason for the reduced endurance, and preventive measures of research has been an important part of the study of the durability of concrete. A large number of studies show that adding some mineral admixtures(such as fly ash,slag powder and silica fume) cement replacement parts, can delay or inhibit Alkali-Aggregate reaction. Current mineral admixtures especially fly ash is widely used at abroad, but in domestic and abroad is still lack of the use of mineral admixtures Alkali-Aggregate reaction prevention standards effective evaluation of mineral admixtures Alkali-Aggregate reaction effect method to guide the application of mineral admixtures. Evaluation of the effectiveness of mineral admixtures methods based on rapid detection method of active aggregate, comparison test after adding mineral admixtures body changes in the inflation rate. This paper mainly studies the mineral admixtures is adopted to Alkali-Aggregate response inhibition. This paper uses the quality of cement to sand ratio of 1:2. 5, water cement ratio of 0.47. At 60 ℃, 1 mol/L- 1alkali bath curing conditions, different dosage, the contents of different varieties admixture inflation rate experiment was carried out. Through test and analysis of the following main conclusions:(1) Mixed with fly ash, silicon ash and mineral powder can effectively restrain Alkali-Aggregate reaction.(2) When a 2:1 ratio of fly ash and slag powder(that is, the incorporation of fly ash, slag powder mixed with 20% and 10%), respond to Alkali-Aggregate reaction inhibition effect is best. Different proportion of compound admixture on Alkali-Aggregate reaction inhibition effect of fly ash and slag powder according to the proportion of sorts, with the following relationships: 2:1>1:1>1:2>1:3>3:1.(3) When a 2:1 ratio of fly ash and silica fume(that is, the incorporation of fly ash, silicon ash is mixed with 10% 20%), respond to Alkali-Aggregate reaction inhibition effect is best.Different proportion of compound admixture onAlkali-Aggregate reaction inhibition effect according to the proportion of fly ash and silica fume, has the following relationship: 2:1>1:1>3:1.(4) Mixing fly ash, slag powder and silicon ash ternary composite admixture of Alkali-Aggregate reaction inflation have very good inhibitory effect. When the total content of30%, the dosage of the three kinds of admixture ratio of fly ash, slag powder, silica fume is4:1:1(i.e., 20% of fly ash, slag powder, silicon ash 5% 5%), the expansion of Alkali-Aggregate reaction inhibition effect is best.(5) The smaller the porosity and the smaller the most probable aperture of the specimen,the smaller the Alkali-Aggregate reaction caused by expansion, this is due to the porosity of thespecimens is reduced, block the flow of pore fluid, thus inhibiting the Alkali-Aggregate reaction;In addition, mixed with fly ash and slag powder can be ash with aggregate reaction, the produce also reduce the porosity of the specimens.