Repairing Concrete Cracks: What Types of Dowels Can You Use?

Concrete with cracks

Concrete is one of the hardest wearing material options you have for your construction. It is, however, still susceptible to a range of elements that could cause your floors or walls to crack. As such, there are now many products used for the repair of concrete cracks. The ideal choice primarily depends on the size of the crack.

For large cracks in concrete, suppliers of concrete sealers like formdirect.com.au often recommend dowel installation. A dowel is a short steel bar that provides a mechanical connection between two cracked concrete slabs.

Dowel installation is generally recommended if your concrete is still structurally sound and the main issue causing the crack is load transfer. The bar increases your concrete’s load transfer efficacy and reduces its joint’s stress and deflection, thus closing the crack and preventing similar problems in the future.

Here are the dowel options you have for concrete repair.

Round Dowels

Wooden hammer with round dowels

These ¾ x 14 x 1 x 16-inch smooth round dowels are often used with 7-8 or 5-6-inch-thick concrete slabs. With 12-inch centre spaces, they carry vertical loads across your structure’s concrete joints and maintain the vertical alignment of your slabs. The dowels also allow the slabs to move perpendicularly to your joints. This is because dowelled concrete joints work like contraction joints and will relieve the shrinkage stress perpendicular to joints.

Square Dowels

These are meant to alleviate the restrained slab movements associated with round dowels, which occur parallel to concrete joints and create tensile stress. The bottoms and tops of a square dowel are not cushioned. Vertical load is hence transferred to the dowel, and the slabs’ vertical alignment is maintained. As such, square dowels are used to repair cracks that occur parallel to your concrete joints. The dowels, like round dowels, should be appropriately aligned to reduce the risk of random slab cracks.

Rectangular Dowels

These are sometimes used interchangeably with square dowels but are considered a variant of plate dowels. They have a decreased bearing stress and better deflection control since they are spread over a larger area compared to the square and round dowels. Rectangular dowels are sometimes used with plastic clips made of compressible material to allow for some misalignment and lateral slab movement.

Refined Plate Dowels

Refined plate dowels are the latest options available. These come in size ranges of 4-6 inches and can be tapered, diamond or double-tapered. They have a more extensive bearing area and eliminate the use of compressible materials on the dowels’ vertical faces for lateral slab movement and misalignment. Depending on your refined plate dowel type, you can have wider spaces between your concrete slabs.

There are several advantages the above dowel options have over other repair products for your concrete cracks. Dowels, for instance, have a higher steel quantity compared to other products. Therefore, they will provide a higher load transfer for your structure while using less steel, reducing your repair expenses. However, you should make sure that you get an expert to install the dowels to guarantee they do not cause further cracks but rather strengthen your structure.