What is Concrete Expansion Joint Filler ?

Definition : The joint spaces, expansion or the concrete joints occurred at the time of construction are filled with sustainable compressible materials. These filler materials used to fill the concrete gaps or spaces are known as joint filler.

Types of Concrete Expansion Joint Filler

Generally there are different types of joint filler materials available in the market. Joint filler materials used can be different from country to country.

Following are the few types of filler materials which are most commonly used are are quite sustainable.

Bitumen Impregnated Fiber Board

Bitumen Impregnated fiber board are extremely durable and light weight fiber board which is widely used. These boards are easy to use, cut and handle. Moreover they do not bleed even in extreme conditions.

They are mostly used to fill the expansion joints in concrete pavements, pedestrian areas, concrete retaining walls and bridges etc.

Soft Wood Joint Filler

Generally small or micro gaps are filled with softwood filler which is also called as sawdust. These are then covered with joint sealer. Soft wood boards are also used sometimes for filling the large concrete gaps or joints.

Based on reports, wood filler boards appear to be the best available, which may be due to their greater capacity to recover.

Because of their considerable resistance to compression, they may also be of structural benefit to the pavement.

Cork Fillers

These are generally of two types – Regular and Self-expanding cork filler. It consist of granulated cork particles combined with inert material.

Glass-Fiber Filler

Glass-Fiber Filler material is combination of both glass fiber and asphalt. Keeping in mind the conditions on site, it is generally manufactured in the form of strips of various thickness.

Due to low content of asphalt material in this filler, it tends to be free from extrusion. Moreover it is less resistant to compression.

Properties of Joint Filler

In order to satisfy the properties of materials to be used as satisfactory filler materials, it should possess following properties :

Compression :

A good joint filler should be capable of adequate compression, that may be needed as the cracks can shrink due to weathering effects. Moreover they should not lose their weight more than 5 % when compressed.

Recovery :

In summer the compressive behaviour of the expansion joint filler should be reversed in winter’s as the joints gets opened. The material has to recover along with the joint.

It it fails to do so, can lead to vacant space in which the the infiltration of water and solid materials into the space can be detrimental.

Extrusion :

The extrusion of one edge should not be more than 6.5 mm when the specimen is compressed to 50 percent of its thickness with three edges restrained.