How To Find The Compressive Strength Of Concrete

Contents

1 What compressive force of physical? How determine the cube compressive strength?
- 1.1 Procedure of determination of compressive strength of concrete
- 1.ii Training of test specimens
  - - ane.2.0.1 Footstep one: Mix blueprint calculation
    - 1.2.0.two Stride 2: Batching of material
    - 1.2.0.iii Step 3: Mixing of concrete
    - one.2.0.4 Step 4: Casting of the specimens and demoulding
    - 1.2.0.5 Step five: Curing of the exam specimen
- 1.iii Per centum of strength gain by cube
- 1.four Exam motorcar used in compressive strength testing
- ane.5 Test process to determine the compressive strength of concrete
- 1.six Calculation of compressive strength of physical example
  - - 1.6.0.1 Follow our previous posts with below links
- i.7 Conclusions on how to determine the compressive strength of concrete

What compressive strength of concrete? How determine the cube compressive strength?

The compressive force of the concrete is the of import parameter as per the blueprint requirements in structures. It is the ability of the structural elements that will comport the load without whatever cracks or deflections. The compressive strength of physical is generally adamant by using universal testing machine (UTM) in the laboratory for the cube specimens.

The strength is by and large adamant at the age of 3 days, 7 days, 14days, 28days, 56days, 90day and 180 days curing periods.

The compressive strength of physical cube is determined by using below formulae

Compressive strength = P/A

Where P = Maximum practical load on cube specimen.

A= Cross sectional area of cube specimen.

Process of conclusion of compressive forcefulness of concrete

The complete compressive force of concrete specimens is determined past using below specified 3 stages

Grooming of test specimens
Testing the compressive strength using UTM
Calculation of compressive force

Training of test specimens

The grooming of exam specimens is the process of making concrete cube from mix blueprint calculation to curing period process.

The below specified steps involves the making the cube specimen in the compressive strength testing.

Step 1: Mix blueprint calculation

Mix design is the process of determining the proportions of materials used to brand concrete. Example cement, fine aggregates, fibroid aggregates and h2o. In guild to summate the mix design of physical specimens we required material properties like specific gravity, fineness modulus, fineness, initial and final setting times, grading of aggregates, water absorption etc. The mix design of concrete is determined by using IS 10262 and IS 456 codes as per the Indian conditions. And other methods like British codes, ACI codes and trial and adjustment methods are also available to make proportions. The complete process of steps used in mix design of physical and mix calculation of M20 grade physical is explained in my previous posts read them with below links.

Adding of mix blueprint of M20 class physical by using IS10262 and IS 456 code

What is mix design of concrete and steps followed in mix pattern adding

Step 2: Batching of material

After determining the mix proportions as per the mix proportions nosotros need to follow the batching of materials. The batching is the procedure of determining the quantity of materials required to make the physical cube specimens. The batching is of 2 types one is volume batching and second one is weight batching. For the perfect concrete mixes we will use weight batching other than volume batching. Volume batching of concrete is used if the density of the materials is less.

Step 3: Mixing of concrete

The next step in the preparation of samples is mixing of physical. Initially the coarse aggregates and fine aggregates are mixed properly then cement is added to the mixture of aggregates and again mix the concrete until it gets uniformity. The water is added to the mix as per the calculations and finally mix again until it gets to uniformity. The prepared physical is called equally fresh concrete and workability tests are used for studying the physical behavior.

Stride 4: Casting of the specimens and demoulding

The cubes of 150mmX150mmX150mm or 100mmX100mmX100mm moulds are used in the casting of cube. After mixing the physical fill the mould with one/3^rd level and meaty with tampering rod with 25 blows, again fill with one more 1/3^rd level and give 25 blows with tampering rod and finally fill the concrete with full physical (another 1/3^rd) and give 25 blows tampering and cease the tiptop surface. After casting procedure is done leave the specimen for 24 hours to get hardening and demould then from the cube moulds.

compressive strength — Casting of cube specimen

Step 5: Curing of the test specimen

After demoulding is washed from the cube moulds the cubes are released in to water tank. The curing of text specimens are generally done for 3days, 7days, 14days, 28days, 56days and 90days time period. Clear portable h2o is generally used in the curing procedure of physical.

Percentage of strength gain by cube

The below table shows the per centum of strength proceeds for the cube specimens for the catamenia of 1day, 3days, 7days, 14days and 28days.

S. No	Curing period	Percentage of strength gain
i	1 day	xvi%
two	3 days	30%
3	7 days	65%
four	14 days	90%
5	28 days	99%

For the 1day the percentage strength gained past sixteen%, for 3days the percentage strength gained by thirty%, for 7days the percentage strength gained by 65%, for xiv days the percentage force gained by 90%, and finally for 28days the percentage strength gained by 99%.

Test machine used in compressive forcefulness testing

The exam motorcar of universal testing machine (UTM) is used to determine the compressive strength of concrete.

compressive strength specimens — Number of cube specimens

Test process to make up one's mind the compressive strength of concrete

The following examination process is used to decide the compressive strength of physical

Take the examination specimen from the curing days required time flow.
Remove the moisture content with wet textile around the specimen.
Keep information technology in the sun light for the 2 to 3 hours in order to removing the wet content from the cube specimen.
Now place the exam specimen in between the two plates of the UTM motorcar.
Now apply the load at the charge per unit of 140kg/m2/min for the specimen.
Apply load until the failure in the specimen is obtained and note the load at which specimen fails.

Calculation of compressive strength of concrete example

The below specified calculation shows the sample compressive strength adding 300kN load.

Compressive strength = Failure load/Expanse

= 300X10³/ (150X150)

= 13.333 N/mm²

Follow our previous posts with below links

What are the different types of foundations used in edifice construction

What are the bones parameters considered in seismic analysis of building

Loads and different types of loads used in edifice design as per structural blueprint

Conclusions on how to decide the compressive strength of concrete

The compressive strength of the physical is the amount of maximum load practical on the cube specimen at which failure occurs. The in a higher place explained concepts are related to the consummate concept of what is compressive strength of concrete and casting of the cube specimen and test procedure to determine the compressive forcefulness of concrete for 1day, 3days, 7days, 14days, 28days, 56days, 90days and 180days curing periods.

For more information related to the civil technology concepts follow my YouTube channel Civil engineering by shravan.

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