Two more trials having variation of + or – 10 percent of water – cementitious material ratio shall be carried out and a graph between these water cementitious materials ratios and their corresponding strengths shall be plotted to work out the mix proportions for the given target strength for field trials . Design mix of M20 grade concrete (with admixture )as per latest code IS 10262 : 2019 Projects requirements . For a better experience, please enable JavaScript in your browser before proceeding.

i) Specific gravity = 3.05. ii) Avg. Concrete mix design is the process of finding right proportions of cement, sand and aggregates for concrete to achieve target strength in structures. comp.

sohaib Salama March 13, 2016 at … Concrete mix design is required to achieve target strength in structures.

( for pumpable mixes 10 % coarse aggregate should be decreased and the same percentage of fine aggregate is to be increased)Volume of coarse aggregate = 0.681 X 0.66 = 0.449 cum Note : 1. There are different grades of concrete like M15, M20, M25, M60, etc. We'll assume you're ok with this, but you can opt-out if you wish. © 2014 bloggercivil.com. … Scribd is the world's largest social reading and publishing site. (a) Characteristic compressive strength required in the field at 28 days grade designation — M 25(d) Degree of workability required at site — 50-75 mm (slump)(e) Degree of quality control available at site — As per IS:456(f) Type of exposure the structure will be subjected to (as defined in IS: 456) — Mild(d) Aggregate are assumed to be in saturated surface dry condition.Himsworth constant for 5% risk factor is 1.65.

Cost of M20 mix design Grade concrete with admixture (Approx) = Rs. Concrete A mix design can be designed in two ways as explained below Nominal Mix Design Nominal Mix It is used for relatively […]

Please enter your email address. Understanding Concrete Grades . 1 Concrete grade : M20 mix design 2 Type of cement used PPC cement ( supplied only with strength of 33 grade as per clause no 7.4.1 page no 2 of IS 1489 ). 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. 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.

All rights reserved. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. It is mandatory to procure user consent prior to running these cookies on your website. Hence volume of fine aggregate = 1 – 0.66 = 0.34 per unit volume of total aggregate . Aggregate shall be used in saturated surface dry conditions if otherwise , when computing the requirements of mixing water , allowances shall be made for the free surface moisture contributed by the fine and coarse aggregate. For Zone II 20 mm nominal maximum size aggregate, Volume of coarse aggregate and fine aggregate = 0.66 per unit volume .