| The bad problems such as poor grain size,high content stone powder,large water demand and big shrinkage were in the mechanism mountain sand in Guizhou province.It was adverse to its application in concrete.The preparation technology of mechanism mountain sand concrete was researched which was supported by the project of Guizhou provincial science and Technology Department,"the preparation of superfine slag powder and its application in high performance grouting material and concrete"(Guizhou Branch GZ(2015)3013).The main research work and achievements were as follows:By using two kinds of graded stone,two kinds of graded sand(mixed with washed sand)and adjusting the sand ratio,we could improve the mechanism sand concrete gradation,reduce the adverse impact of concrete raw material fluctuation and improve the concrete workability.By adjusting air-entraining agent and defoamer,we found that the mixing performance,strength and other performance of concrete had improved most when air-entraining agent、defoamer was 3.5、2.5 ten thousandth respectively in the admixture.By using P.O52.5 cement preparation of concrete,we reduced the amount of cement and water,the shrinkage of concrete and improved its long-term durability.The mechanical properties and durability of the mechanism sand concrete were improved by adding fiber.The preparation technology of phosphorus slag powder concrete was studied.The effect was studied which phosphorus slag on the physical and mechanical property and microstructure of cement and morta;Orthogonal contrast test was designed of slag powder and fly ash concrete,To improve the performance of concrete,the mixing ratio technology of phosphorus slag powder concrete was studied.The effects were studied of the specific surface area of phosphorus slag powder,the proportion of phosphorus slag powder and fly ash,the ratio of phosphorus slag powder and fly ash instead of cement on the working performance and mechanical properties of concrete.The results showed that the phosphorus slag powder with specific surface area 1300m2/kg,phosphorus slag powder and fly ash ratio of 80%:20%,composite powder instead of cement ratio 20%(C2B3A3orthogonal combination)C30 concrete showed best work performance,the best mechanical properties in this case.Durability tests of electric flux,shrinkage and carbonation of concrete were conducted.The result showed that the slag powder could reduce the electric flux,the shrinkage and carbonization depth of concrete,and improved the durability of concrete.The reason was that the micro filling effect of phosphorus slag powder decreased the porosity of the cementitious material and enhanced its compactness.The pozzolanic reaction of phosphorous slag powder also increased the density of the product.The result of the concrete SEM diagram showed that the glass body material surface of the phosphorus slag powder could improve the microstructure of the concrete.At the same time,some of glass crystal products produced by the secondary hydration reaction of the slag powder concrete were wrapped on the surface of the concrete,which improved the microstructure of the concrete and the compact packing effect.Energy spectrum and quantitative structure analysis showed that the percentage of phosphorus content of ultrafine phosphorus slag powder concrete reached 0.9%,the atomic percentage reached 0.7%.The test has played a role in the verification.The results of XRD showed that the phosphorus slag was involved in hydration reaction to produce some aluminum phosphate products in the hydration system,which played a role in retarding the early reaction of the concrete and created favorable conditions for the better generation and compact accumulation of the later reaction product.The high performance green sand concrete was successfully applied to Guiyang light rail project.For the first time,the application of the slag powder mechanism sand concrete in the light rail was realized.The comprehensive benefit of the prepared concrete was analyzed. |
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