What Is the Definition of Construction Joint?
A construction joint is a type of concrete joint that is used when a new section of concrete is poured next to an already set section of concrete. A construction joint's purpose is to allow for some horizontal movement while remaining rigid against rotational and vertical movement. Construction joints keep the concrete structure from collapsing prematurely.
A well-functioning joint system is critical to the success of a cement concrete road. Tie bars and dowel bars reinforce the pavement at joints and serve as load transfer devices. The first reason for jointing concrete pavements is that concrete shrinks with age. This is accomplished through a variety of mechanisms.
Drying shrinkage happens when water is used for hydration while also being lost to the atmosphere through evaporation. Thermal shrinkage in concrete is caused by the heat of hydration.
As the cement is mixed with water, the mixture heats up. Heat is released as the concrete hardens and cools, and the pavement shrinks. Chemical shrinkage occurs because the cement hydration products (concrete) take up less volume than the reactants (cement and water in addition to aggregates).
Pavement Joint Types in Cement Construction:
As the cement is mixed with water, the mixture heats up. Heat is released as the concrete hardens and cools, and the pavement shrinks. Chemical shrinkage occurs because the cement hydration products (concrete) take up less volume than the reactants (cement and water in addition to aggregates).
Pavement Joint Types in Cement Construction:
The following are some pavement joint types in cement construction:
- Transverse joint
- Longitudinal joints
Transverse Joint:
Transverse construction joints are used at the end of a paving run or where the pavement is broken. The locations are commonly referred to as headers in practise. Because, unlike contraction joints, these joints have a flat interface, some form of embedded steel is required to either transfer load or prevent the joint from opening. Dowels can be installed in new concrete or in holes drilled into an existing header. Tie bars can also be inserted into previously drilled holes in a header using fresh concrete or epoxies. Transverse building joints can be sawed or formed. The resulting header must be sawed if a slip-form paving machine runs out of concrete.
Longitudinal joints
Longitudinal construction joints are used to connect lanes that have been paved in separate passes. Tie bars are commonly used with longitudinal construction joints to ensure that the joint remains tight and that the lanes do not separate.
The Advantages of Using a Construction Joint
- The free horizontal movement of the floor is limited by its vertical movement.
- Optimal load transfer.
- Protection at the perimeter
- Crack prevention due to thermal variations
- Correctly joining two concrete slabs.
