http://huagfit.webs.com/apps/blog/ 蚊帐|女装品牌大全|http://www.wenzha.net/|http://www.letaod.com/|Turn :conventional C10 ,C15 ,C20 ,C25 http://ablf5.blogcn.com/,C30 concrete mix proportion of concrete strength are divided into a number of intensity levels ,the strength grade of concrete in compressive strength standard values of FCU ,K division . The cube compressive strength standard values are the cubic compressive strength distribution in a value ,strength is less than the worth of not more than 5% ,namely 95% guaranteed rate .The strength of concrete is divided into C7. 5 http://manint.blogcn.com/,C10 ,C15 ,C20 ,C25 ,C30 ,C35 ,C40 ,C45 ,C50 ,C55 ,C60 and so on twelvegrades .relationresultConcrete mix ratiorefers to the concrete component materials ( cement http://0mwpmx.blogcn.com/,water ,sand ,stone ) the proportion of the relationship between . There are two kinds of methods : one is the 1cubic meters of concretein a variety of materialshttp://dnvvw.blogcn.com/, such as cement, 300kg,180kg,690kgof water ,sand ,gravel, 1260kg;another is the unit of mass and the ratio of cement material and concrete water cement ratio ,for example :C precedent . : S: G = 1 : 2.3:4.2,W / C = 0.6 .relationresultCommongrade , relationresultC20:175KG:343kg:621kgcement sand stone :1261kg mixture ratio: 0.51 : 1:1.81:3.68relationresultC25:175KG:398kg:566kgcement sand stone :1261kg mixture ratio: 0. 44 : 1:1.42:3.17relationresultC30:175KG:461kg:512kgcement sand stone :1252kg mixture ratio: 0.38 : 1:1.11:2.72......concrete mixing ratio reference :relationresultCementconcrete grade ratio ( units) of Kng slump compressive strength of mm N / mm2 cement sand stone water 7 days28 days3007341236195352129. 012.45P.C32.5C204.120.65 C253207681153208451932.112.403.600.6535.211.953.05C30 370721112720745290.56C35 4306421094172443244.111.492.540.404805721111202503450.711.192.31C400.42P.O 32.5C20 2957071203195302029. 112.404.080.66C25 3167191173192502232.412.283.710.6137.611.823.23C30 366665118218750270.51C35 42963711842006030* * * 6.211.482.760.47 C40478 * * *11282106029.451.011.332.360.44 P.O32.5RC25 32174911731935026 39. 112.333.650.6044.312.013.15C30 360725113419860290.55C35 4316431096190503951.311.492.540.4451.011.192.31C40 480572111120240390.42P.O 42.5(R ) C30 35267612021905529 * * * 5.211.923.410.54C35 3866431194197503449. 511. 673.09 0.51C40 3986491155199553955.311.632.900.504966061297223453855.911.222.610.45C50PII42.5RC30 34865212121885031 * *6.011.873.480.5450.511.683.12C35 380639118719450350.51C40 3986491155199553955. 311.632.900.50C45 46261811472034* * * 2.759.111.342.480.444806331115192254562.811.322.320.40C50P.O52.5RC40 39264511971965340 55.811.643.050.50C45 456622115619* * * 243.559.511.362.530.434686261162192304561. 611.332.47C500.41thistest data obtained using standard laboratory ,sand medium sand ,fineness modulus is 2.94 ,gravel was 5 ~ 31.5mm continuous particle size .Each grade concrete ratio can also be adjusted by admixture . relationresultThe grade of concretewith strength grade , relationresultLong-term since,our country according to the compressive strength of concrete grade ,and the label characterization .In 1987 GBJ107-87 standardwith strength expression . DL / T5057-1996 design code for hydraulic concrete structures ,DL / T5082-1998 freezing resistance design standard of hydraulic structures ,DL5108-1999 code for design of concrete gravity dam ,with strength expression ,therefore the new standard is to strength expression so that uniform titles . Hydraulic concrete in addition to meet the design strength indicators, but also to meet the impermeability http://qwobj.blogcn.com/,frost resistance and ultimate tensile strain indicator .Many large hydropower station project are an important part of concrete ,often said to the durability of concrete freezing and thawing index or ultimate tensile elongation index as the main control parameters . The past label to describe the intensity grade ,is the cube compressive strength standard values as Chinese words ,such as 200,300 etc..relationresultAccording tothe relevant standards, the strength grade of concrete to concrete English name first letter plus its strength standard values to express . Such as C20 ,C30 etc. .relationresultHydraulic concretewith strength only to grade is not enough .Hydraulic concrete classification, should be based on multi index grade to the characterization of . The design put forward 4 indexessuch as C9020 ,W0.8 ,F150 ,with the p0.85 x 10-4,i.e. 90 d compressive strength of 20 MPa ,impermeability capacity reached 0.8 MPano seepage ,freezing and thawing capacity reached 150 freeze-thaw cycles,the ultimate tensile strain of reaching 0. 85 x 10-4.As the level of hydraulic concrete in these 4 indicators should be tied ,with either an index to characterize the is not right .As hydropower project ,also part of buildings and other structures engineering ,design presents only the compressive strength http://ilorv.blogcn.com/,the strength to grade ,as the age for 28 d,with C20 ,C30 said . relationresult2 concrete strengthand its standard value change , relationresultIn order tolabel expression of concrete strength grading of the original system, compressive strength of concrete by using to express . According to the relevant standards, building materials strength unified by the symbol f .Compressive strength of concrete for fcu .Among them, Cu cube .And the compressive strength of the FCU http://grj1.blogcn.com/,K expression K ,which is the standard value meaning ,such as concrete strength grade of C20 ,FCU ,k = 20N/ mm2 (MPa ) ,namely the cube compressive strength standard values for 20MPa28d. relationresultHydraulic structureconcrete generally adopt 90d or 180d age,so the C symbol plus age subscripts http://adq3s.blogcn.com/,such as C9015 ,C9020 refers to theage of 90d compressive strength standard values for 15MPa,20MPahydraulic concrete strength grade http://425tw.blogcn.com/,C18015 said to 180d agecompressive strength standard values for 15MPa. relationresultThe 3 measurement unitchange , relationresultPastour country uses metric units of measurement ,the strength of concrete units for kgf / cm2 .According to the State Council has published the relevant laws ,to the implementation of the international system of units as the basis of the legal units of measurement system, in the system of units http://selin.blogcn.com/,the basic unit is the N ( Newtonian ) ,therefore ,the strength of the basic unit of 1 N / m2 ,can also be written 1Pa . Label instead of strength grade of concrete strength measurement ,units in the international system of units of expression .As a result of N / m2 (Pa ) ,numerical value is too small, the general 1N /mm2 = 106N/ m2 (MPa ) as the concrete strength of the practical use of the units of measurement ,read as Newtons per square millimeter or mpa .