Influence Of Mineral Compositions On Compatibility Of Cement And Water Reducer

The compatibility of cement and water reducer has been the first essential problem inliquid concrete producing and construction. The adaptability of cement and waterreducer is influenced by many factors.The main cement of Heilongjiang was classified according to the content of aluminatein this paper in order to research the compatibility between cement and water reducer.And then test the influence of cement fineness, gypsum type, type and dosage of mixingmaterials to cement adaptability between cement and water reducer. Besides, this paperobserved the relationship between cement paste fluidity and rheological parameters andanalyzed the mechanism of water reducer to paste and mortar on the basis of rheologyand adsorption theory. Through the test of cement hydration degree, this thesis showedthe influence of water reducer on hydration. Finally, experiment of concrete verified theeffect of water reducer on brief working property and mechanics performance ofconcrete.The results of experiment show that: the compatibility between cement and waterreducer is affected by the type of cement and water reducer, which influenced bycement composition and molecules form, production process of water reducer.The lessthe total content of C3A and C4AF, the better adaptability between cement and waterreducer. The compatibility is also influenced by cement fineness, gypsum type, the typeand quantity of mineral admixtures. When the fineness of A cement increases from 322m2/kg to 369m2/kg, the quantity of water reducer increased by 1.0% under the samefluidity conditions.The fluidity of cement paste can reach 260mm by adding 4% ofnatural gypsum and the average fluidity grews by 20mm one hour later.The average fluidity also grews by 20mm with the quantity of fly ash between 20% and30%. Adding the slag into cement will increase the saturated admixtures of waterreducer. When the amount of slag is 20%,30% and 40%,the saturated admixtures ofwater reducer is increased by 0.5%,0.2% and 0.6% respectively.Cement rheological research shows that: rheological parameters of the net decreaseswith an increase of fluidity. The yield strength remains unchanged if fluidity less than220mm for C. Once the fluidity over 220mm the yield strength Fells rapidly from 440Pato 273Pa. And for B cement slurry, only the fluidity greater than 225mm, its yieldstrength Quickly from 542 Pa descend to 313 Pa.Experimental of mortar results shows that: the saturation point of N water reducer inmortar of B and C are 1.7% and 1.3% which increases by 0.8% and 0.6% respectively.According to the experiment of cement hydration level, Aliphatic series water reducer doesn't affect the cement hydration after 1d. Water reducer can make concrete structurecompact, reduce the water and improve interface structure. The 3d strength ofconcrete increased by 78% and the 28d strength 58% at least,with adding waterreducing agent.