GRADES OF CONCRETE AND IT’S APPLICATIONS
GRADES OF CONCRETE AND IT’S APPLICATIONS: In this lecture I am going to discuss about the various grades of concrete in which I will introduce you about grades of concrete
1.concrete cube test.
2. The groups of concrete grades
3. Types of concrete grades and their ingredient ratios
4. uses of different grades of concrete
Concrete Grade its minimum strength after 28 days of construction with proper quality control. grade of concrete is the designation of concrete according to its compressive strength. According to Indian standards, concrete grade is generally represented by letter ‘M’, which is followed by a number for example M20. The ‘M’ represents mix design of concrete and the number represents its characteristic compressive strength in N/mm² at 28 days, which is obtained from concrete cube test. Now, the question arises.
CONCRETE CUBE TEST
The purpose of performing the concrete cube test is to determine the compressive strength of a concrete element. The cubes used for this test have a dimension of 150 × 150 × 150MM as per IS456 2000. Concrete grades are categorised as per their compressive strength based on Qube test.
GROUPS OF CONCRETE
Generally, there are three groups of concrete grades.
The first one is ordinary concrete, which is represented by M10 M15 and M20. The second one is standard Concrete, which is represented by M25 M30 M35 M40 M45 M50 and M55.
The third one is high strength concrete, which includes M60 M65 M70 And M80,
TYPES OF CONCRETE GRADES
let’s discuss the various types of concrete grades and their ratio.
[ ] The M10 grade of concrete includes a mix ratio of 1:3:6 in which ONE PART of cement is mixed with THREE PARTS of fine aggregates or sand and SIX PARTS of course aggregate with adequate quantity of water having a compressive strength of a 10N/mm² at 28 days after mixing.
[ ] M15 grade of concrete Includes a mixed ratio 1:2:4 with compressive strength, 15N/mm² at 28 days after mixing.
[ ] For M20 grade of concrete The mixed ratio is 1:1.5:3 in which one part of cement is mixed with 1.5 parts of fine aggregates or sand and 3 parts of course aggregates. This type of grade has a compressed strength of 20 N/mm² at 28 days .
[ ] M25 grade of concrete It has a mixed ratio of 1:1:2 With a compressive strength of 25 N/ MM² at 28 days. The mix ratio for concrete grades About 25 is not specified in the code, hence, we need to design the proportion of ingredients for such grades of concrete, keeping in mind the economy in proportioning strength and durability. Based on the construction site, the proportions resulting from the mixed design or tested for their strength with the help of compressive strength test on concrete cubes.
[ ] ,M30 grade of concrete, we need to prepare a design mix ratio and make calculations after performing tests on costly cubes from this mix. Keep the result exceeds 30N/mm², then we can adopt such ratio.
USES OF DIFFERENT GRADES CONCRETE
[ ] The M10 and M15 grade of concrete are used for PC C that is plain cement concrete works such as bedding for footing levelling course, etc.
[ ] M20 is using for RCC that is reinforced cement Concrete work such as slabs, beams, columns, footing etc. Under mild exposure conditions.
[ ] M25 M30 and M35 grades are used for R CC works like foundations, footings, columns, beams and slabs etc.
[ ] M40 grade is used for prestressed concrete works in slabs, beams, columns ,footings etc.
[ ] M45, and M50 grades are using for R CC works in runways, concrete roads prestressed beams at etc.
[ ] M55 grade is used in pressurised concrete girders and piers .
[ ] M60 and M80 are used where there is a need of high compressive strength.”high-rise buildings, long span bridges, etc., use such construction techniques.” These grades are used when the constructions are to be done in aggressive conditions. So this was all about this lecture