Study On Mix Proportion Design Of Concrete Based On The Surplus Coefficient Of Paste

The production and application of green high performance concrete is the important direction of ready-mixed concrete industry today.With the advancement of the urbanization process and the construction of super-large projects,higher requirements on the quality and performance of concrete have put foreard.Therefore,it is the choice of the new area to research and explore a design method which is suitable for the development of morden construction engineering.The traditional concrete mix proportion design method has more empirical formula and table ignoring the importance of the maximum compactness theory,which could improve the performance of concrete.In additional,schoolars in China and abroad explored many methods that need to establish a complex particle structural model,like the the shape of particle model and average thickness of paste model,which is difficult to be used in the production of concrete.The paper based on the theory of maximum compactness,the concrete can be divided into aggregate and cement materials system.We could get the relatively compact system of two materials through the method of theoretical research and experiment analysis.Putting forward the concept of surplus coefficient of paste,and researching the influence of it on various performance of concrete to get the optimal section of the coefficient.Combining the absolute volume method,a new design method of concrete was established.The main content of this paper includes:(1)Has been studied and analysised the concrete proportion ratio method with domestic and abroad.On the basis of the principle of maximum compectness,making aggragate system and cement materials system as the carrier.Summarizing the grading of aggregate optimization method and the calculation model of the density of cement materials.(2)In the past,the grading optimization is to separate the coarse and fine aggregate,which is rarely used as an aggregate system,and summaring the gradation optimization methods and the sieving standards.Through sieving optimization on manufactured-fine sand and coarse aggegrate,and combined aggegrate particles,making the volume of all grain size meeting specification requirements and strengthen the packing density is the main idea.Design three kinds of water-binder ration concrete using the optimized aggegrate to testing,and the results showed the slump of the concrete with waterbinder ration(0.45?0.40?0.35)have been increased by(14.2%?9.8%?13.1%),The compressive strength of 28 d have been respectively increased by(7.3MPa?8.1 MPa 5.4 MPa).(3)In order to achieve the maxiumum compactness of cementing materials,the influence law of mineral material proportion to binary system and ternary system is analysized by TOUFAR calculation model and testing.Getting the fly ash and slag reasonable proportion that could make the packing structure more stable and the packingstate more closely in binary and ternary system,is 20% and 25% respectively.In addition,the test make tpaste density and air content as the breakthrough point verified the optimum dosage of fly ash and slag.(4)The influence of the volum of paste that have filled in the vois of aggregate on various performance of concrete can be quantitatively analyzed.Design two kinds concrete with water-binder ratio is 0.45 and 0.35,researching the influence of the surplus coefficient of paste to the workability,compressive strength,volum stability and durability performance of concrete.The test results showed the optimum section of two kinds concrete with water-binder ratio(0.45and0.35)is(0.21,0.27)and(0.58,0.65),then,established the concrete mixture proportion design method based on the surplus coefficient of paste.