Concrete is defined as a casting material in construction, made of mixed components of cement, sand, gravel, or coarse aggregate and admixture with a suitable proportion of water. Sign Up to The Constructor to ask questions, answer people’s questions, write articles, and connect with other people. PROPERTIES OF THE M25 GRADE CONCRETE: M25 is a mixture composed of cement, fine aggregates and coarse aggregates with a ratio of 1:1:2 is 1cement, one sand, and two aggregates. Here are only four major components that are usually required for concrete formation. Concrete mix design is the process of finding right proportions of cement, sand and aggregates for concrete to achieve target strength in structures. You will receive a link and will create a new password via email.Sorry, you do not have permission to ask a question, You must login to ask question. Mostly M25 and M30 always used in construction industries for multistory buildings.To understand deeply about Grade of concrete have you ever imagine in which amount of component (Cement, sand, coarse aggregate and admixture) used in concrete.For example, M20 Grade Stands for Ratio of concrete 1:1.5:3 which is 1 bag of cement, 1.5 baskets of sand, and 3 baskets of course aggregate are mixed with a suitable proportion of water.“M” denotes the mix of the component in the designated proportion of sand, cement, gravel or coarse aggregate, admixture, and water in according to Grade ratio, For example, M30 in which “M” represents the mix Ratio and number (30) represent the compressive strength in MPa (Mega Pascal).From the grade of concrete, we can find the mixed proportion of all design concrete ratio.

With corrected proportions three concrete cubes are cast and tested for 28 days compressive strength.A summary of all the trial mixes is given in the following Table.From Compressive Strength vs. c/w graph for target strength 31.6 MPa we get,= 1 – [{448.6/(3.15 x 1000)} + (197.4/1000)] = 0.660 mA reduction of 0.05 in w/c will entail and increase of coarse aggregate fraction by 0.01.Mass of coarse aggregate = 0.660 x 0.568 x 2.84 x 1000 = 1064.65 kg/mMass of fine aggregate = 0.660 x 0.432 x 2.64 x 1000 = 752.71 kg/mGopal Mishra is a Civil Engineer from NIT Calicut and has more than 10 years of experience in Civil Engineering and Construction. Please enter your email address. So, concrete mix design can be stated as Concrete Mix = Cement:Sand:Aggregates.The concrete mix design involves various steps, calculations and laboratory testing to find right mix proportions. In the present example water cement ratio is raised to 0.55 from 0.5.An increase of 0.05 in the w/c will entail a reduction in the coarse aggregate fraction by 0.01.Hence the coarse aggregate as percentage of total aggregate = 0.558 – 0.01 = 0.548= 1 – [{(358.9/(3.15 x 1000)} + (197.4/1000)] =0.688 mMass of coarse aggregate = 0.688 x 0.548 x 2.84 x 1000 = 1070.75 kg/mMass of fine aggregate = 0.688 x 0.452 x 2.64 x 1000 = 821 kg/mFor casting trial -3, mass of ingredients required will be calculated for 4 no’s cube assuming 25% wastage.Volume of concrete required for 4 cubes = 4 x (0.15Mix is stable, cohesive, and workable and had a true slump of about 75 mm.So , it has achieved desired workability by satisfying the requirement of 50-75 mm slump value .In this case water / cement ratio is decreased by 10% keeping water content constant.A reduction of 0.05 in w/c will entail and increase of coarse aggregate fraction by 0.01.= 1 – [{438.7/(3.15 x 1000)} + (197.4/1000)] = 0.664 mMass of coarse aggregate = 0.664 x 0.568 x 2.84 x 1000 = 1071.11 kg/mMass of fine aggregate = 0.664 x 0.432 x 2.64 x 1000 = 757.28 kg/mFor casting trial -4, mass of ingredients required will be calculated for 4 no’s cube assuming 25% wastage.Volume of concrete required for 4 cubes = 4 x (0.15A local correction due to moisture condition of aggregate is again applied on this proportions. This process is usually adopted for structures which requires higher grades of concrete such as M25 and above and large construction projects where quantity of concrete consumption is huge..

a) Grade designation : M25 b) Type of cement : OPC 53 Grade conforming IS 12269 c) Maximum nominal size of aggregate : 20mm d) Minimum cement content : 300 kg/m 3 (IS 456:2000) e) Maximum water-cement ratio : 0.50 (Table 5 of IS 456:2000) Thus, large concrete construction projects use concrete mix design. workability, bleeding and finishing qualities.Mix is cohesive, workable and had a true slump of about 25 mm and it is free from segregation and bleeding.So modifications are needed in trial mix 1 to arrive at the desired workability.To increase the workability from 25 mm to 50-75 mm an increase in water content by +3% is to be made.The corrected water content = 191.6 x 1.03 = 197.4 kg.As mentioned earlier to adjust fresh concrete properties the water cement ratio will not be changed.