నైరూప్య

Requirement of Different Grades of Cement for Nominal and Design Mix M20 Grade Concrete

S. Mishra, Dibyendu Pal

Concrete is one of the most common construction material generally produced by using locally available ingredients with binding material. Ingredients are used as per known or designed proportion, termed as nominal or design mix concrete respectively. In nominal mix concrete, properties of ingredients are not considered and same is limited up-to M20 grade only. For present work, 43 and 53 grade ordinary Portland cement (OPC) was used in nominal and design mixed M20 grade concrete and required cement content was compared. Using 40 mm size graded Requirement of Different Grades of Cement for Nominal and Design Mix M20 Grade Concrete S. Mishra1, Dibyendu Pal2 Associate Professor, Department of Civil Engineering, NERIST, Nirjuli, Arunachal Pradesh, India1 Assistant Professor, Department of Civil Engineering, NERIST, Nirjuli, Arunachal Pradesh, India2 angular aggregate and zone II river sand, nominal mix concrete (1.0 : 1.5 : 3.0) was prepared. Density and cement content of fresh concrete were 23.45 kN/m3 and 390.83 kg/m3 respectively. Using same ingredients, nominal mix concrete was prepared using ratio given in IS 456 : 2000 table – 9 and the cement content was found 366.30 kg/m3. Nominal mix M20 grade fresh concrete was again prepared by using 20 mm size angular coarse aggregate and cement content was obtained as 366.52 kg/m3. Design mix proportions were calculated by using 43 and 53 grade OPC with 40 mm size graded angular aggregate and zone II river sand. Cement content was found 49.10 kg/m3 less for 53 grade ordinary Portland cement and cement saving was 4.08% over 43 grade cement. In design mix M20 grade concrete, with 40 mm CA, zone III river sand and 43 grade OPC, cement content was 347.37 kg/m3 and in comparison to nominal mix concrete cement saving was 38.46 kg/m3. In M20 grade design mix concrete with 20 mm CA, 43 grade OPC, and zone II river sand, cement content was 383.51 kg/m3 against 366.52 kg/m3 required for nominal mix concrete proportioned by ratio suggested by IS 456 : 2000.aggregate, river sand, cement saving.