Dowels are located in transverse joints of Jointed Plain Concrete Pavements (JPCP) and they are used to provide load transfer between individual slabs, reduce faulting and improve performance.
When should you dowel concrete?
When a joint is created, some level of load transfer can be achieved by aggregate interlock between the two concrete slabs at the joint. However, higher traffic loads (especially trucks) increase the stresses on the slab edges beyond this level, so dowel bars are recommended to provide load transfer.
What is the difference between dowels and rebar?
Dowel bars are cast or drilled into concrete and used to transfer loads across joints. Rebar is generally used for the reinforcement of concrete, it can be supplied cut and bent to BS8666 and threaded to BS3643.
What are dowel bars in concrete slab?
Dowel bars are short steel bars that provide a mechanical connection between slabs without restricting horizontal joint movement. They increase load transfer efficiency by allowing the leave slab to assume some of the load before the load is actually over it.
What is the minimum dowel spacing?
The cages perform no function other than initial alignment assistance. Dowel bars are typically 32 to 38 mm (1.25 to 1.5 inches) in diameter, 460 mm (18 inches) long and spaced 305 mm (12 inches) apart.
Do you need dowels in concrete?
Joints of concrete pavement are stressed by the effects of overruns of heavy vehicles and temperature and moisture gradient of concrete slabs. The dowels in transverse joints must allow horizontal movement of slabs in the contracting time after the pavement is paved and during its further use.
How deep should concrete dowels be?
Vertically, the dowel bar should normally be located at mid-depth of the slab. With respect to horizontal spacing, dowel bars are typically placed 12 inches apart, starting with the first bar 12 inches from the edge of the slab.
Why do we use dowel bars?
The primary advantage of dowel bars is to transfer load without restricting horizontal joint movements due to temperature and moisture expansion and contraction in the concrete slabs. Also, dowel bars play a role to maintain the vertical and horizontal alignment of slabs.
Where dowel bar is provided?
Dowel bars are placed across transverse joints in concrete pavement to allow movement. They are inserted at the mid-depth of the slab and coated with a bond-breaking material to restrict bonding to the PCC. Thus dowels help to transfer loads allowing expansion and contraction of adjacent slabs independently.
Are dowels reinforcement?
Dowels are commonly used as interface reinforcement between columns or walls and footings. The dowels are set in the footing prior to casting the footing concrete and are subsequently spliced to the longitudinal bars in the column or wall.Oct 1, 2019
What are rebar dowels used for?
Rebar dowels are used to brace the joints between two concrete elements. When the rebar is not being used to hold the concrete members together, post-installed anchor theory can be applied. This eliminates the need to embed the bar deep enough into the base material to develop the rebar for steel failure.