Why are concrete joints needed?
Concrete has immense compressive strength, but not much tensile strength. Which is the primary reason we provide reinforcements inside concrete. However, some structural members, or some parts of them have to be made without reinforcement. What happens when these come under unexpected tensile stress?
One of the reasons of unexpected tensile strength is that concrete undergoes shrinkage over time. This creates tensile stress inside the member automatically which is hard to foresee. Now, if the tensile force being generated over time is gradually rises above the member's tensile strength, then it will, eventually, crack the concrete. Which, as you can expect, may have disastrous effects.
This is exactly why concrete joints are needed. Joints are provided in concrete in order to prohibit, or, at least minimize the possibility of cracks appearing automatically due to shrinkage from time or temperature changes.
One can say, joints in concrete are pre-planned cracks. They are created at portions where there the concrete is expected to undergo tension most, regulating the tensile forces there and pre-empting the formation of cracks.
Types of Concrete Joints
There are four kinds of joints provided in concrete slabs or pavements depending upon the need or the expected scenario. They are as follows:
- Construction joints
- Expansion joints
- Contraction joints
- Isolation joints
Published By
Arka Roy
www.constructioncost.co
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