Research To Maoming Kaolin Byproduct Activation And Its Preparation Of High-performance Concrete

Maoming Kaolin is very local characteristics of mineral resources, with abundant reserves and the good crystallization. However, the development and utilization of Maoming kaolin is far from enough, especially coated with kaolin have a lot of byproduct (nearly 30% of the total number) to become a byproduct, not only did not receive effective use of resources, the environment offered a certain amount of pressure.In view of the present, metakaolin as a concrete high-activity mineral admixture have be studied more and more at home and abroad , and some studies show that their activity may be more than silicon gray. In this paper, the basic characteristics and the activation of Maoming Kaolin byproduct have had a detailed study, and it had been used to made high-performance concrete as a high mineral admixture.The structure of kaolin byproduct have characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), integrated thermal analysis instrument, the surface area of Maoming, etc. characterized the activation of metakaolin, kaolin has explored the best calcined kaolin activation process; On this basis, the work performance, physical and mechanical properties and durability of high-performance concrete used high-activated metakaolin have been studyied,comparied with silica fume and rice husk ash. The results show that high-strength concrete strength with high-activated can be comparable with silica fume, strength rating to 100 MPa.1,X-ray found that the composition of Maoming Kaolin byproduct and ore is slightly different, in addition to kaolinite phase, byproduct also contains about 13% of the quartz phase.the activity of kaolin is slingtly low than kaolin ore. Another analysis by SEM found that the crystal degree of kaolin byproduct is very good.2, from the re-analysis of the heat between Maoming kaolin ore and byproduct ,can see that the calcined temperature range between kaolin byproduct and ore Tended to the same, hydroxy started taking off when about 530°C, generating metakaolin to the 1007℃occurred recrystallization, generating Spinel.3, through the totally study of activation system of Metakaolin ,proved that it can be a greater impact on activity of Metakaolin .the best calcination temperature of Metakaolin is 700 - 800℃. considered the impact of activity and water from surface area of Metakaolin,I think the best grinding time of Metakaolin is 1 h.4, As surface area, water demand Metakaolin to a certain extent, as a Super ash materials the Application is to be restricted.Studied the composite of the partial role in improving the performance of kaolin.Proved that metakaolin and fly ash, slag-doped cement can greatly improve the compatibility of superplasticizer; increase the compressive strength of cement; improve the micro-structure of cement slurry. Metakaolin, slag and fly ash three-doped is the best.5, compared analysed hydration products and cement concrete interface of no admixture and adding metakaolin, silicon dust, rice husk ash through X-ray, scanning electron microscopy and other means of micro-testing. Compared to non-doped cement, Partial-doped kaolin, the hydration products of silica fume cement is mainly calcium silicate hydrate CSH,AFT, and Ca (OH)₂ can not be finded . the active component in metakaolin and silica fume can reacte with Hydration products of cement clinker to create the CSH gel and AFt .and the outcome can fill in the pores, so that cement paste can form dense structure conducived to the growth of cement strength.6, passed by the comparative study of the relevant characteristics in concrete work, strength and durability of kaolin and silica fume that calcined, prove that the concrete preparated with metakaolin strength reached 117 Mpa, slump of 25 cm, expansion of 63cm, diffusion coefficient of 9.285E-10cm²/s.and can be comparable to silica fume, meet the technical requirements of high-performance concrete, and it is the ideal preparation minerals Admixture.