Wednesday, May 8, 2019

Concrete Test on Green or Fresh Concrete and Hardened Concrete

Concrete test on green or fresh concrete and hardened concrete is required to check concrete quality such as workability, impermeability, compressive strength etc. We described all concrete test on green concrete and hard concrete.



Test on Green or Fresh Concrete


  1. Workability test
  2. Initial and Final Setting time test
  3. Air content
  4. Density or Unit wei1ght


Workability test

Workability or Slump is a measure of consistency, or relative ability of the concrete to flow and pour in any shape of form work. If the concrete can’t flow because the consistency or slump is too low, there are potential problems with proper consolidation. If the concrete won’t stop flowing because the slump is too high, there are potential problems with mortar loss through the form work, excessive form work pressure, finishing delays and segregation.


Concrete Test on Green or Fresh Concrete and Hardened Concrete


Initial and Final Setting time test

The initial setting time and final setting time are the time intervals required for the mortar sieved from concrete mixture to reach the prescribed penetration resistance after the initial contact of cement and water.


Air content

Air-entrained concrete is typically specified in areas of the country where frost-related damage can occur. The measurement of air content in fresh concrete of normal density is typically performed using the pressure method.


Density or Unit weight

The density or unit weight of concrete is measured using a Type B pressure meter to verify agreement with the approved project mix design. The information obtained through this test can also be used to determine yield and relative yield, which helps you verify that you are getting the volume of concrete you ordered and paid for. You can also use this data to calculate the air content of the mix.


Test on Hardened Concrete

There are two types of test for hardened concrete.

  1. Destructive test
  2. Non-Destructive test


Destructive Tests on Concrete

  1. Compressive strength test on cubes
  2. Compressive strength test on cores
  3. Tensile strength test

Compressive Strength test on Cubes

Concrete compressive strength is determined by cube strength test of concrete.
Concrete cube specimens are tested by compression testing machine after 7 days curing or 28 days curing. Load should be applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails.

Concrete Test on Green or Fresh Concrete and Hardened Concrete

Compressive Strength test on Cores

Concrete cylindrical cores are cut from the finished structure with a rotary cutting tool. The core is capped and tested in compression to give a measure of the concrete strength in the actual structure. The ratio of core height to diameter and the location where the core is taken affect the strength. The strength is lowest at the top surface and increases with depth through the element.


Tensile Strength test

The concrete structures are highly vulnerable to tensile cracking and hence the determination of tensile strength of concrete is very important.


Non-Destructive Test on Concrete

  1. Rebound hammer test ( hardness test )
  2. Ultrasonic pulse velocity test
  3. Pull out test

Rebound Hammer test

Rebound hammer test is required to find out the compressive test of concrete by using rebound hammer.
Rebound hammer test is a Non-destructive test (NDT test of Concrete) which is used to test the Compressive strength of concrete without any damage. Moreover, the best part of Rebound hammer test is concrete can be tested in real time at the site instead of going to the lab without any damage.


Ultrasonic Pulse Velocity test

Ultrasonic pulse velocity (UPV) test is an nondestructive test to check the quality of concrete. In this test, the strength and quality of concrete is assessed by measuring the velocity of an ultrasonic pulse passing through a concrete structure.
This test is conducted by passing a pulse of ultrasonic through concrete to be tested and measuring the time taken by pulse to get through the structure. Higher velocities indicate good quality and continuity of the material, while slower velocities may indicate concrete with many cracks or voids.


Pull Out Test

The principle behind pull out testing is that the test equipment designed to a specific geometry will produce pull-out forces result that closely correlate to the compressive strength of concrete. This correlation is achieved by measuring the force required to pull a steel disc or ring, embedded in fresh concrete, against a circular counter pressure placed on the concrete surface concentric with the disc/ring.



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Tuesday, May 7, 2019

Concrete Grades,Types, Ingredients, Properties and Strength

Concrete is a construction material composed of cement, fine aggregates (sand) and coarse aggregates mixed with water which hardens with time. Concrete Grades,Types, Ingredients, Properties and Strength details you can find here.



Concrete Grades

Grades of concrete are defined by the strength and composition of the concrete, and the minimum strength the concrete should have following 28 days of initial construction. The grade of concrete is understood in measurements of MPa, where M stands for mix and the MPa denotes the overall strength.


Grade of Concrete        Mix Ratio      Compressive strength in 28 days
                                 M5                  1 : 5 : 10                 5 MPa
                               M7.5                  1 : 4 : 8              7.5 MPa
                                M10                  1 : 3 : 6               10 MPa
                                M15                  1 : 2 : 4               15 MPa
                                M20                   1 : 1.5 : 3               20 MPa

Standard Grade of Concrete


                                M25                  1 : 1 : 2               25 MPa
                                M30                 Design Mix               30 MPa
                                M35                 Design Mix               35 MPa
                                M40                 Design Mix               40 MPa
                                M45                 Design Mix               45 MPa


High Strength Concrete Grades

                                M50                 Design Mix               50 MPa
                                M55                 Design Mix               55 MPa
                                M60                 Design Mix               60 MPa
                                M65                 Design Mix               65 MPai
                                M70                 Design Mix                70 MPa


Concrete Grades,Types, Ingredients, Properties and Strength
Concrete pouring

Type of Concrete

  1. Normal Strength Concrete
  2. Plain or Ordinary Concrete
  3. Reinforced Concrete
  4. Prestressed Concrete
  5. Precast Concrete
  6. Light – Weight Concrete
  7. High-Density Concrete
  8. Air Entrained Concrete
  9. Ready Mix Concrete
  10. Polymer Concrete
    1. Polymer concrete
    2. Polymer cement concrete
    3. Polymer impregnated concrete
  11. High-Strength Concrete
  12. High-Performance Concrete
  13. Self – Consolidated Concrete
  14. Shotcrete Concrete
  15. Pervious Concrete
  16. Vacuum Concrete
  17. Pumped Concrete
  18. Stamped Concrete
  19. Limecrete
  20. Asphalt Concrete
  21. Roller Compacted Concrete
  22. Rapid Strength Concrete
  23. Glass Concrete

Concrete Ingredients


1. Cement
2. Coarse aggregate
3. Fine aggregate
4. Water


1. Cement 

The cement and water form a paste that coats the aggregate and sand in the mix. The paste hardens and binds the aggregates and sand together.
Portland cement is the commonly used type of cement for production of concrete.

2. Coarse aggregate

Gravel or crushed stone is the coarse aggregate.

3. Fine aggregate

Sand is the fine aggregate.

4. Water

Water is needed to chemically react with the cement (hydration) and to provide work-ability of concrete. The amount of water in the mix compared with the amount of cement is called the water/cement ratio. The lower the w/c ratio, the stronger the concrete. (higher strength, less permeability)  

Concrete Grades,Types, Ingredients, Properties and Strength

Concrete Properties

1. Concrete gain strength in presence of water, but most of the materials rust or decay when they are wet.
2. Concrete can be moulded to any shape at normal temperature and pressure.
3. Concrete resist attack of insects.
4. Concrete is fire and sound proof.
5. Strength of concrete is high.
6. Strength of concrete can be further increased by reinforcement, prestressing etc.
7. Concrete becomes stronger with age.
8. Frequent repairs, painting etc not required for concrete.
9. It is economical and strong compared to other construction materials.
10.Concrete can be pumped to any difficult places.
11.The material for concrete is easily available.
12.Concrete can be used to apply modern construction techniques for modern construction works.



Compressive Strength of Concrete

Compressive strength is the ability of material or structure to carry the loads on its surface without any crack or deflection. A material under compression tends to reduce the size, while in tension, size elongates.


Compressive Strength of Concrete at Various Ages


The strength of concrete increases with age. Table shows the strength of concrete at different ages in comparison with the strength at 28 days after casting.
AgeStrength percent
1 day16%
3 days40%
7 days65%
14 days90%
28 days99%

Compressive Strength of Concrete at 7 and 28 Days

Grade of ConcreteMinimum compressive strength N/mm2 at 7 daysSpecified characteristic compressive strength (N/mm2) at 28 days
M151015
M2013.520
M251725
M302030
M3523.535
M402740
M453045

Concrete Mix Design

Concrete Mix Design is all about achieving target strength, water cement ratio and perfect proportions of Cement, Sand and Aggregate to produce a good concrete to achieve its target strength.




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