Research On Technical And Economic Optimization Of Ready-mixed Concrete

With the continuous development of national economy and meeting humanrequirements for environment is becoming increasingly difficult, the harmoniousdevelopment of cement concrete industry and the environment is an urgent need tosolve the problem in today’s concrete industry. In concrete materials, the production ofa ton of cement will emit about a ton of carbon dioxide gas and the gas has greatinfluence on the greenhouse effect. The great emissions of industrial waste residuebrought huge burden for the ecological environment in today’s world, so it is necessaryto carry out "green concrete" research,in order to achieve the goal that reducing theamount of cement and improving the performance of concrete.This paper focuses on researching the effects of mineral admixture on mechanicalproperty and durability of concrete, because of the limited time, only researched andanalysed the effect of batch charging mix technology on the strength of ordinaryconcrete. Used portland cement, sand and grave and PC water reducers as raw materials,designed mixture ratio of C40concrete in laboratory, according to the workingperformance and mechanical properties of mineral admixture concrete, got the optimalmixing ratio of mineral admixture concrete, and then measured the durability of theoptimal mix of mineral admixture concrete. Under the same mixture ratio, comparedstrength of ordinary concrete that used ready-mixed cement mortar method, netready-mixed cement slurry method and method of sand and gravel enveloped withcement and traditional method. Through the above research draws the followingconclusions:(1) Analyzed the performance of different dosage of mineral admixture concreteand ordinary concrete, the results indicate that the working performance of concrete issignificantly improved after mixed with mineral admixture in the concrete, theperformance about slump, adhesiveness and water retention are higher than ordinaryconcrete. With the amount of fly ash increases, the early strength of concrete decreases,but the late strength of fly ash concrete development fast, much higher than ordinaryready-mixed concrete. When the concrete compound mineral admixture, improved theproperties of low early strength of fly ash concrete, fly ash replaced50%of cement andslag’s dosage is a third of fly ash, its strength can still reach the strength of ordinaryconcrete at28d age. If achieve the same strength of concrete, it can save50%of cement, and the economic benefits generated by the best.(2) Compared the durability of the best dosage of mineral admixture concrete andordinary concrete, because of fly ash and slag incorporation, the dosage of cementconcrete was reduced, caused alkaline of concrete decreases and carbonization degreewas higher than ordinary concrete. In view of this phenomenon, in the actual project cantake measures to increase the thickness of the protective layer to improve theperformance of its carbonation. And mineral admixture of concrete hydration heat issmall, adiabatic temperature changed slowly. In addition, due to the active effect ofmineral admixture, C-S-H gel material in concrete increased, blocking the diffusionchannel, made the concrete structure became more compact, thus improved theperformance of mineral admixture concrete resistance to chloride ion penetration.(3) When used batch charging mix technology, because built shell in the mixingprocess, improved the concrete interface structure and improved the strength ofconcrete, the effect of methods of ready-mixed cement mortar and sand and gravelenveloped with cement was better than the effect of method of net ready-mixed cementslurry. Compared with ordinary ready mixed concrete, it could save about15%ofcement when achieved the level of C40concrete design strength, and had a certaineconomic benefits.(4) In a word, adopting the technology of using a large amount of fly ash orsecondary composite mixing techniques, they can reduce the using amount of Portlandcement and reduce project cost, improve the performance of concrete and have the dualeffect of social and economic benefits.