C20 concrete density
I. Design parameters Concrete strength: fcu.k=30Mpa Cement type and strength grade: Yuzhou Tianrui P.O42.5, surplus coefficient γc= 1. 13 Material type, origin and gradation: Zhangzhou Asai Stone Factory,
Gravel adopts 5-25mm continuous grading. Gravel mix ratio:16-31.5mm:10-20mm: 5-10mm = 35: 33: 32 sand origin and specifications: Biyang medium sand water: drinking water slump: 70mm-90mm II. Calculation parameters assume concrete density: 20mm.
Thirdly, the mix design is 1, and the strength FCU is prepared. O = FCU。 K+1.645 υ = 30+1.645× 5 = 38.2mpa 2, and the actual cement strength FCE = γ c× 42.5 1.65438. ce/(？ cu0+αa×αb×？ Ce)W/C=0.56 According to experience, W/C=0.504 is selected. According to the variety and particle size of coarse aggregate and construction requirements, the slump of concrete mixture with unit water consumption is 70 mm-90 mm. The water consumption is 197kg5, the calculated cement consumption is known as mwo =197kgw/c = 0.50mco = 395kg6, the sand ratio βs=34%7, and the calculated sand consumption is MSO+MgO = ρ cp-mco-mwomso/(MSO+MgO
Fourth, the benchmark mixture ratio MCO: MSO: MgO: MWO = 395: 615:193:197 =1:1.56: 3.02.
5. After trial mixing, the slump is 89mm, and the cohesiveness and water retention are good, and other work performances meet the work requirements. The bulk density ρcp=2400kg/m3, and the difference between them is less than 2.0%, so it is unnecessary to adjust.
What is the mix proportion of c20 concrete?
Preliminary calculation of C20 concrete mixture ratio
Design steps:
1, determine the concrete mixing strength fcu, o =1.645× 5+20 = 28.2mpa.
2, calculate the water cement ratio (w/c)
3. Selected unit water consumption (Mwo)
As the maximum particle size of crushed stone is 3 1.5mm, the water consumption of concrete is: MWO = 180kg/m3.
4. Calculate the unit ash consumption (Mco)
(1) Calculate the unit ash consumption according to the strength.
5, choose sand ratio (βs)
According to the maximum gravel size of 3 1.5mm and water cement ratio w/c=0.57, the selected concrete sand ratio is βs=34%.
6, calculate the amount of sand and gravel
(1) adopts the mass method.
Known unit ash consumption Mwo= 180 Kg/m3, sand ratio βs=34%.
Assume that the wet apparent density of concrete mixture Pcp=2400 Kg/m3.
The obtained sand dosage Mso=647Kg/m3 and crushed stone dosage Mgo= 1257Kg/m3.
That is1:0.57: 2.05: 3.98 w/c = 0.57.
Knowing the mix proportion of C20 concrete, everyone certainly wants to know the price, but the prices of cement and sand in each region are different, so the price of C20 concrete is different, but the average is around 350/ m2.