Experimental Research Of The Impact Of Water-Cement Ratio On Each Cement Concrete Mechanical Indices

With the economical development of our state, burden communication increases fast.Cement concrete pavement possess the dominance of enduring and gets a comprehensive application in pavement of high-grade expressway.Now , the outstanding problem of the pavement of newbuild or remodelled roads is the breakage not long after brought into use.One of the major reasons of the breakage of cement pavement is the lackage of pavement intensity.The intensity of cement concrete mostly includes compressive strength,folding strength and cleavage strength three indices.Folding strength is usually ussed as strength test index in the course of engineering construction.So it has tight contact with the quality of concrete pavement. But the specimens and stamps are as heavy as 70kg that we can not move them easily.So in practice constructions,we usually test compressive strength to commute into folding strength.After construction,we need make sample survey of the whole way about its quality instance.One of the most routine methods is coring to get its cleavage strength,which can be convert into folding strength to assess the quality of the construction.Therefore, the relationship between intensity and water-cement ratio of road-use cement concrete and the relationship between compressive strength, folding strength and cleavage strength become a most important problem for a lot of highway operator these year.Establishing empirical formula of concrete intensity which precision is met utility require has important signification in alleviating experimentation labour intensity and enhancing quality control of concrete.Whih a vast territory of our country, we have got a complex situation. Considering the difference of factors such as raw materials and climatic condition,the empirical formulas we have can not conform each specific instance in our country .And the relationship between each intensity index and water-cement ratio, the relationship between compressive strength, folding strength and cleavage strength may be change greatly.In this article,we did some research on the relationship between compressive strength, folding strength and cleavage strength,based on performance index experimentation of road-use cement concrete in Changchun region.The paper consist of five chapters totally.The emphzsis parts are chapter two and chapter four.Chapter one mainly talks about the significance and purpose of this study,and the research actuality of the relationship between each intensity index and water-cement ratio reserarch status.Learning about research status,we can see that a lot of people have done research on influencing factors of concrete intensity and they found that water-cement ratio is the most important one.In consideration of the relationship between different kinds of mechanics indices has very important sense in decreasing labour intensity and enhancing quality control, scholars both here and abroad have brought forward a series of empirical formula to describe relationship of them.At the same time,the diversification of concrete intensity influencing factors lead to indetermination relationship between these indices. This experiment relies on the local material of Changchun.Chapter two introduces the experimental course of concrete performance test of cement for road-use,including elemental material test,which proved the materials meet the application standard of concrete.After that,we did the mix ratio design for concrete.After ascertaining the base water-cement ratio,we brought forward five mix ratio of concrete for behavioural experiment which can fit the use of cement for road-use based on the test purposes.The simple mathematical relationship between different kinds of indices are got after simple conceptual analysis of test result is proceed.Chapter three introduces the elementary theories and measure of regression analysis. Modern technology of concrete can not get away from the mathematical statistics measure applied in concrete test. This chapter introduces the method of linear regression in mathematical statistics, including elementary theory, calculation procedure, statistical test, analysis of variance and so on. This chapter indicates the extensive use of mathematical statistics in cement concrete experimentation,which establishes the foundation for the fitting of various relationship of cement concrete in the measure of mathematical statistics in the next chapter.Chapter four is the hardcore of the paper.First of all,we proceed fitting on compressive strength and folding strength by the measure of multivariate linear regression which starts with analyse of influencing factors on the intensity of concrete.We can find that air content is one of the most important influential factors of compressive strength besides water-cement ratio.But the most important one of folding strength is water-cement ratio.In practice,we should enhance the control of air content to guarantee concrete compressive strength. This chapter fits the relationships of folding strength and compressive strength, flexural strength and cleavage strength by the measure of linear regression.Each relationship is multi-feasibility on the base of observing scatter.So fitting contrastive analysis about multi-potential scatter is done so as to select a optimized fitting measure.Then we get a conclusion that exponentiation relationship is the best fitting measure in describing the relationships above.In the end we brought forward empirical equations which fit into the concrete of changchun.Chapter five is the summary of the paper in which the content and direction are also pointed out for further study.