Study On Confecting High Performance Concrete With Metakaolin And Muti-Mineral Admixtures

Based on the summarizing development and application of high performance concrete and mineral admixtures, and according to a low degree of crystal and the feature of the high pozzolanic activity of metakaolin which kaolin has been heat treated by 800 C in 2 hours , this thesis applied the metakaolin to high performance concrete and then did the application symmetrically.This thesis mainly studies high performance concrete made by metakaolin and silica fume mixed respectively with fly ash and slag, and discusses the feasibility of metakaolin replacing silica fume as active mineral admixture by analyzing the workability, mechanical properties, durability and microstructures of the testing samples. It still presents the evaluation index of activity of mineral admixture, that is, strength effect coefficient , . Higher Ks caused greater strength which be presented bymineral admixture to high performance concrete. At the same time, it studies the influence of the multi-admixture to the high performance concrete,During the contrastive experiment of compound admixing metakoalin and silica fume to high performance concrete, we found that using metakaolin as active mineral admixture to confect high performance concrete had a quite good fluidity and its slump is more than 200mm; the concrete admixing metakaolin and concrete admixing silica fume both had similar compressive strength and tensile spliting strength. But the concrete admixing metakaolin has a better performance in anti-brittleness. In the side of endurance, the concrete admixing metakaolin and concrete admixing silica fume both have a good performance of anti-corrosion and anti-penetrating. But in anti-shrinking,metakaolin has more influence on the concrete 's early-shrinkage. We still found that the multi-mineral admixtures can increase the quantity of hydrate gel, improve the quality of the gelatin, decrease the quality of Ca(OH)2 produced by cement, weaken the negative effect of Ca(OH)2, advance the density of rigidified grout, so to enhance the strength of product greatly. Thereby, the multi-admixture has an active infection to the structure and strength of high performance concrete.