Preparation And Study Of Portland Cement With Strength Grade Of 62.5 MPa

With the rapid development of our society, the demands of high-grade concrete and its productions will increase greatly. Using high-grade strength cement replace low-grade strength cement for making concrete, can reduce the amount of cement and the cost of concrete preparation and improve the durability of concrete. Reducing the amount of cement and increasing the service life of concrete, it is obviously conducive building materials industry to save energy and reduce discharge amount of pollutions, which will contribute to building materials industry taking the road of sustainable development. Currently, the Hong Kong-Zhuhai-Macao Bridge Project,which is key state sea-crossing engineering, has been clearly put forward the need to using 62.5 strength grade of Portland cement. The topic rely on Guangdong TaPai Group Co. Ltd.'s, aim to prepare 62.5 strength grade of Portland cement by using normal clinker, and finally to come to industrial production.On the one hand response to the needs of Hong Kong-Zhuhai-Macao Bridge construction project;on the other hand , development technology that product 62.5 strength grade of Portland cement by using clinker ordinary , expanding the company's cement products to increase enterprise technical reserves and market competitiveness, and promote enterprise's progress and development.Combined with Guangdong TaPai Group Co. Ltd.'s condition of cinker,the study made technical scheme to preparation 62.5 strength grade of Portland cement with ordinary cinkler through measure that improved cement particle size distribution and hydration process by using enhanced grinding aids. The paper study the effect of gypsum dosage and different using method of grinding aids and different specific surfaces on the strength and other performance of cement., and then prepared 62.5 strength grade of Portland cement by optimized combination.According to the gypsum dosage test, the optimal dosage range of SO3 was 2.54% ~ 2.96%;when the specific surface was close ,the strength test show that the strength of cement adding grinding aids at the process of grinding was higher than the cement adding grinding aids after grinding, and the compressive strength is greater than 65.0MPa, but the the adaptability of additives was worse,and water requirement of normal consistency was larger; increasing specific surface, the early strength increased significantly, but the later strength ineffectively, the adaptability of additives become bad ,and water requirement of normal consistency was larger ,and the effect of grinding aids on improving cement strength decreased.Cement was made by optimizing the combination of 2.54% SO3, adding 0.03% GF-443 grinding aids to grind cement and the specific surface of 390±10㎡/㎏,finally the 3d and 28d compressive strength each was 34.4MPa and 67.3MPa,which reached the strength requirement of P·I62.5R cement. Then did cement added admixtures test. The result show that when added 5% active admixtures with specific surface of 604㎡/㎏,3d and 28d compressive strength of cement each was 33.0MPa and 65.6MPa, and reached the strength requirement of P·I62.5R cement.The paper studied the effect of grinding aids on the the hydration of portland cement through bound water determination, hydration heat analysis. The result show that GF-443 grinding aids accelerated hydration rate and heat within 28 days.