Compressive Strength of Concrete Cubes - Lab Test & Procedure

In this case standard deviation is taken from IS:456 against M 20 is 4.0.Maximum water-cement ratio for Mild exposure condition = 0.55Based on experience, adopt water-cement ratio as 0.5.Maximum water content = 186 Kg (for Nominal maximum size of aggregate — 20 mm)Estimated water content = 186+ (3/100) x 186 = 191.6 kg /mMinimum cement Content for mild exposure condition = 300 kg/mThis value is to be checked for durability requirement from IS: 456.In the present example against mild exposure and for the case of reinforced concrete the minimum cement content is 300 kg/mVolume of coarse aggregate per unit volume of total aggregate = 0.62Volume of coarse aggregate per unit volume of total aggregate = 0.62 x 90% = 0.558b) Volume of cement = (Mass of cement / Specific gravity of cement) x (1/100)c) Volume of water = (Mass of water / Specific gravity of water) x (1/1000)d) Volume of total aggregates = a – (b + c ) = 1 – (0.122 + 0.1916) = 0.6864 me) Mass of coarse aggregates = 0.6864 x 0.558 x 2.84 x 1000 = 1087.75 kg/mf) Mass of fine aggregates = 0.6864 x 0.442 x 2.64 x 1000 = 800.94 kg/mFor trial -1 casting of concrete in lab, to check its properties.For casting trial -1, mass of ingredients required will be calculated for 4 no’s cube assuming 25% wastage.Volume of concrete required for 4 cubes = 4 x (0.15Since the aggregate is saturated surface dry condition hence no correction is required.The mix proportion as calculated in Step 6 forms trial mix1. Concrete mix design is the process of finding right proportions of cement, sand and aggregates for concrete to achieve target strength in structures. 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..Benefits of concrete mix design is that it provides the right proportions of materials, thus making the concrete construction economical in achieving required strength of structural members. Grade of concrete is defined as the minimum strength the concrete must posses after 28 days of construction with proper quality control. The “M” refers Mix and Number after M (M10, M20) Indicates the compressive strength of concrete after 28 days of curing and testing.. M indicates the proportion of materials like Cement: Sand: Aggregate (1:2:4) or Cement: Fine Aggregate: Coarse Aggregate.. Please enter your email address. There are different grades of concrete like M15, M20, M25, M60, etc. VIP members get additional benefits.Lost your password? HenceVolume of all in aggregate = 1 – [{394.8/(3.15×1000)} + {197.4/(1 x 1000)}] = 0.6773 mMass of coarse aggregate = 0.6773 x 0.558 x 2.84 x 1000 = 1073.33 kg/mMass of fine aggregate = 0.6773 x 0.442 x 2.64 x 1000 = 790.3 kg/mFor casting trial -2, 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 very cohesive, workable and had a true slump of about 60 mm.It virtually flowed during vibration but did not exhibit any segregation and bleeding.So , it has achieved desired workability by satisfying the requirement of 50-75 mm slump value .In case of trial mix 3 water cement ratio is varied by +10% keeping water content constant. 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. Volume of all in aggregate He is the founder of The Constructor.Concrete Mix Design Calculation for M20, M25, M30 Concrete with Procedure & Example 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. If we mention M10 concrete, it means that the concrete has 10 N/mm2 characteristic compressive strength at 28 days. With this proportion, concrete is manufactured and tested for fresh concrete properties requirement i.e. ~ The grade of concrete is the minimum strength that the quality controlled concrete posses after 28 days of the construction. Mostly M25 and M30 always used in construction industries for multistory buildings. How to select suitable concrete grade for construction?Regular Grades of Concrete and their Uses What is Grade of Concrete?

Component of Concrete . Grade of concrete is denoted by prefixing M to the desired strength […] Here are only four major components that are usually required for concrete formation. 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) VIP members get additional benefits.Login to The Constructor to ask questions, answer people’s questions, write articles & connect with other people. 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. As, the quantity of concrete required for large constructions are huge, economy in quantity of materials such as cement makes the project construction economical.Concrete Mix design of M20, M25, M30 and higher grade of concrete can be calculated from example below. Compressive strength of concrete depends on many factors such as water-cement ratio, cement strength, quality of concrete material, quality control during the production of concrete, etc. Test for compressive strength is carried out either on a cube or cylinder.