5 Important Properties Of Concrete You Should Know As A Construction Professional

Important properties of concrete

In this post, you’re going to learn about the five important properties of concrete.

Learning these will help you to make defectless concrete structures.

So let’s discuss these without further ado.

5 Important Properties Of Concrete

1. Strength Of Concrete

Compressive strength is the most important property of concrete.

Besides compressive strength, concrete has some other strengths. Such as:

  • Tensile strength;
  • Bending strength; and
  • Shear strength.

However, concrete is weak in tension.

That means the tensile strength of concrete is neglected.

And, there is no relation exists between compressive, tensile, bending, and shear strength of concrete.

But, it may be mentioned here that typically:

  • The tensile strength is 10% of the compressive strength;
  • Bending strength is 15% of the compressive strength; and
  • The shear is approximately 20% of the uniaxial compressive strength.

But, what is the uniaxial compressive strength of concrete?

The uniaxial compressive strength (UCS) is the maximum axial compressive stress that a right-cylindrical sample of concrete can withstand before failing.

It is also known as the unconfined compressive strength.

But, how do you know the strength of concrete?

For this, several tests are carried out.

Such as:

  • Compression test;
  • Flexure test;
  • Split tensile strength test, etc.

I’ll briefly describe the compression test below. Because it’s the most performed concrete test.

Compression Test:

For this, three specimens are made with freshly mixed concrete of three different batches.

The specimens can be cubes or cylinders.

The size of the cube is 150 x 150 x 150 mm.

And, the cylinder size is 100 mm in diameter and 200 mm in height.

After that, the specimens are cured in water for 28 days.

And then, they are taken to the testing lab.

In the lab, the specimen is placed between the platens of the compression testing machine and applied a gradual load of 14 N/mm2/minute until the specimen is crushed.

Concrete Cylinder test

Once the specimen is crushed you can now calculate the compressive strength.

And the formula is,

= Maximum crushing load ÷ Cross-sectional area of the specimen

Normally, three specimens are tested and the average result is taken.

2. Workability

I think concrete is the most popular building material because of this property.

Due to this property, we can give concrete any desired shape, and smooth finish.

Simply saying, the workability of concrete makes us able to comfortably work with concrete.

Mainly, the water-cement ratio determines the workability of concrete.

The more water you add to concrete the more it’ll become able to work with.

Theoretically, 0.4 water-cement ratio is enough for the chemical reaction of cement and for maximum concrete strength.

But it is also required to compact the concrete properly to get maximum concrete strength.

And this can be obtained by increasing the water-cement ratio.

So the water content in fresh concrete should be such that we can:

  • Handle concrete without segregation;
  • Place concrete without loss of homogeneity;
  • Compact concrete properly, and
  • Give a smooth concrete finish.

That is the good workability of concrete.

In the above discussion, we have just discussed the water content that affects the workability of concrete.

But here are some other factors that also affect workability:

  • Concrete mix proportion;
  • Aggregate size;
  • The shape of aggregates;
  • The surface texture of aggregates;
  • Grading of aggregates, and
  • Admixtures.

But how do you measure the workability of concrete?

There is a popular test practiced in construction to measure this. The test is named Slump Test.

Here is a step-by-step procedure of the slump test.

3. Durability

Because of this property, concrete can resist weathering action, chemical attack, abrasion, or any other process of deterioration.

And, can retain its original form, quality, and serviceability.

But there are various factors that can affect the durability of concrete. Such as:

  • Permeability;
  • Frost Action;
  • Sulphate Attack;
  • Organic Acids;
  • Carbonation;
  • Mineral Oils;
  • Vegetables and Animal Oils and Fats;
  • Sewage;
  • Thermal Effects;
  • Cracks, etc.

Yet, concrete can be a durable product with proper:

  • Design;
  • Proportioning;
  • Placement;
  • Finishing;
  • Testing;
  • Inspection, and
  • Curing.

4. Creep

This is a property of hardened concrete.

Due to this property, concrete tries to deform under sustained load.

That means long-term load or stress on concrete can change its shape.

And, this change occurs in the direction the force is applied.

That’s why, when we stacked any heavyweight materials on a slab during the construction period, we provide supports below the slab.

5. Shrinkage

Concrete shrinkage is the change in concrete volume in the absence of load in a way it decreases the dimensions of the concrete.

And thus it produces cracks in concrete.

Shrinkage increases with high w/c ratio and high cement content.

The good news is, the rate of shrinkage decreases with time.

There are various types of shrinkage. Such as:

  • Plastic Shrinkage
  • Chemical Shrinkage
  • Autogenous Shrinkage
  • Drying Shrinkage
  • Thermal Shrinkage
  • Carbonation Shrinkage

Conclusion

Concrete has many other properties. Some of them are physical properties, some are mechanical properties and some are chemical properties.

I have just discussed Five concrete properties here.

Now I would like to hear from you:

Which concrete property is the most important to know as a construction professional in the list above?

Or did I miss any important property of concrete here?

Or maybe you have a question about something you read.

Either way, let me know by leaving a comment below right now.

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