What is the additional property of concrete? ~ Civil Experiences

• A minimum grade of concrete for R.C.C. (reinforced cement concrete) for any construction work is M20 in normal condition and M30 in seawater condition

• You can use a higher grade of concrete as per structure requirement & condition of the environmental condition but not less than given in IS 456:2000 which I also describe above

• also create a mix design after all required test perform and carried out quantity estimation of cement, sand, aggregate and admixture if any by manually or by using excel sheet

• Unit weight of R.C.C is 25 KN/m3 

• In each estimation of materials need unit weight without that estimation is not possible so you have knowledge about unit weight of each and every material which related to the civil fieldwork on site 

• read this article for unit weight: Unit Weight for Civil Engineering Materials

• We conduce varies tests/Specimens for concrete to calculate fck value

• Hence for design purpose, we fix certain fck values by using a formula which given in IS 456:2000 which use in the design grade of the concrete mix as per required

fck = fcm – 1.65?

• characteristic compressive strength (fck)

• fcr = 0.7√fck

• its also called “Initial tangent modulus” or short term elastic modulus

• Ec = 5000√fck

• It defined as the increase in deformation with time under constant load

• Creep coefficient ⊖ = (creep strain/elastic coefficient)

• Where ⊖ is 2.2 for 7 days, 1.6 for 28 days and 1.1 for 1 year time

• Long term modulus of elasticity = Short term elasticity/(1 + ⊖) or Ec/(1 + ⊖)

• Ordinary concrete is varying from M10 to M20 grade of concrete

• Standard concrete is varying from M25 to M55 grade of concrete or mix design of concrete

• High strength concrete is greater than M60

• NOTE: max cement content = 450Kg/m3