Abstract: The main aim of this project is to provide the general mix design for any grade of concrete, so that, this project contains the mix design for M40 grade of concrete, as per IS 10262:2009. In this project, the mix shall be designed to produce the required grade of concrete having the designated workability, and characteristic compressive strength, which will not be less then the appropriate values as per IS 10262:2009.by this project, the required mix design will be obtained by changing the corresponding values with respective areas. Then we can obtain the required mix design for different grades of concrete.
In this project, general mix proportion is providing us the general procedure for nay grade of concrete. In the field of construction, concrete is the main material made up of different type of materials. The concrete is of different grades and each grade of concrete is useful for different properties and place. Generally these are two type of concrete,
1. By Designing 2. By Adopting
1. By designing the concrete mix, concrete is called as Design Mix Concrete.
2. By adopting the concrete mix, concrete is called as Nominal Mix Concrete.
From the above two type of concrete, design mix concrete procedure is applied in this project. The mix design procedure shall be selected to ensure the workability of fresh concrete. As per IS 456:2000, several information should be provided for design mix concrete pg.no 22.
Design Mix Concrete
Design mix concrete is the type of concrete used in construction, to produce the grade of concrete having the required workability and characteristic strength nominal mix, will reduce the cement content which is used in concrete reduce the water cement ratio also will increase the strength. In this project, general procedure has been given for the concrete of grades very from this procedure of M40grade of concrete the different grades such as M40 to M40 has been obtained by changing the values as per Indian standard 10dis. so it is much easier to design the mix ratio for grade of concrete up to M40.
Characteristics compressive strength (fck) = 40 Mpa
Maximum cement content = 450kg/m
Degree of workability = 0.8 compacting factor
Grade of cement = OPC 53
Specific gravity of cement = 3.15
Specific gravity of sand = 2.6
Specific gravity of aggregate = 2.6
Maximum size of aggregate = 20mm
1. Target mean strength for mix design
The target mean compressive strength at 28 days is given by,
fck = fck+ts
= 40+1.65*5 (t= 1.65 and s = 5) from
= 48.25 N/mm²
2. Selection of water cement ratio
W/c ratio = 40% from IS 456:2000 table no: 5
3. Selection of water content
Maximum water content for 20mm aggregate = 180 Kg.
4. Estimation of entrapped air
Entrapped air = 2% for 20mm aggregate (from IS 10262:1982 table3)
5. Determination of cement content
Cement content = mass of water/ (w/c ratio)
= 450 kg/m³
6. Determination of coarse and fine aggregate:
fa = 623.63 kg/m³
= 1084.95 kg/m³
For the design mix concrete, it is necessary to do the initial test for all materials which are going to be used in concrete. Like wise the result of the initial test are equal to the appropriate values provided in the Indian standards. So it is noted that, the materials can be used in the concrete for design mix concrete.
To check out the theoretical results as per Indian standard with the practical results. The cubes will casted and cured and tested.
Compressive strength test
From the design mix concrete, the results are necessary to be equal, for that the cubes of size 50mmX150mmx 150mm have been casted. The casted cubes are to be tested for 3rd day, 7day and 28th day. The result of this will be compared with the target mean strength of theoretical values which are obtained.
The authors are thank full to Mr.M. Vadivel and Mr.M.Praveen Kumar professor of Civil Engineering Department at Nehru Institute of Technology, Coimbatore.
From this project it is concluded that, the comparison between the theoretical results and laboratory test results are compared, which are almost equal, so we concluded that the design mix concrete is better than nominal mix concrete.
1 Concrete mix proportioning-guidelines IS 10262:2009
2 Recommended guidelines for concrete mix design IS 10262:1982
3 Plain reinforced concrete-code of practice IS 456:2000
4 SP 23 (1982): Handbook on concrete mixes [CED 2: Cement and Concrete].
5 IS 516 (1959): Method of test for strength of concrete [CED 2: Cement and concrete]