All categories
Featured selections
Trade Assurance
Buyer Central
Help Center
Get the app
Become a supplier
(589 products available)
Ready to Ship
Expansion joint sealant is a type of flexible material that is used to fill and seal joints or gaps in structures such as buildings, bridges, roads, and pavements. The main purpose of the sealant is to accommodate movement caused by temperature changes, structural shifts, and other factors while preventing the ingress of water, dust, or other contaminants.
There are various types of sealants used in expansion joints. These include:
Silicone Sealants
Silicone sealants are very versatile, as they can be used in almost any application. Silicone sealants are very durable and flexible, thus ideal for expansion joints in high-movement areas. In addition, they are water and weather-resistant and have the ability to resist mold and mildew. Nonetheless, silicone sealants cannot be painted and are usually more expensive than other options available.
Polyurethane Sealants
This type of sealant is very elastic and has the ability to bond well with concrete, metal, and other substrates. They are very durable, hence making them ideal for outdoor use. Polyurethane sealants are paintable, in addition to offering good resistance to abrasion. They also have UV protection properties which help in prevention of degradation caused by ultraviolet light. However, polyurethane sealants are sensitive to moisture during curing and this can be an issue in certain applications.
Acrylic Sealants
Acrylic sealants are ideal for low-movement joints. They are easy to apply and can be painted over, thus making them suitable for interior applications or exterior use when paintability is very essential. Though acrylic sealants are less flexible than silicone or polyurethane, they can be used for crack repairs in concrete or masonry structures.
Bituminous Sealants
These sealants, commonly referred to as asphalt-based sealants, are primarily used in roofing applications. They provide good adhesion to bitumen and other asphaltic materials. They are waterproof and weather-resistant, therefore ideal for sealing expansion joints in asphalt pavements or roofs.
MS Polymers (Modified Silicone) Sealants
These sealants combine the best properties of silicone and polyurethane sealants. This gives them great elasticity and durability properties. They are UV-resistant, paintable, and do not contain solvents. Therefore, they will not cause damage to building materials. Modified silicone sealants cure quickly and are elastic and flexible enough to accommodate movement in expansion joints.
Expansion joint sealants are materials that are used to fill and seal joints or gaps in structures. The sealants have a wide range of applications within the industrial setting. These include:
Building Construction
Sealants are critical in maintaining the structural integrity of buildings. They are used around windows, doors, curtain walls, and other areas to provide protection against water infiltration, air leakage, and energy loss. To achieve this, they are used in facades where they accommodate the movement of different building materials, thus preventing cracking or damage.
Bridge Engineering
Bridge expansion joints are critical components of bridge design and construction, as they allow the bridge to expand and contract with temperature changes. These joints protect the bridge structure from cracking or other forms of damage. Sealants added to these joints help to prevent water, debris, and other contaminants from entering and causing the joint to deteriorate.
Roads and Pavements
Sealants are used in sealing cracks and joints, hence preventing water penetration and extending the life of the pavement. They help in minimizing the amount of water that enters into the ground or subgrade beneath the pavement, which can cause erosion, structure failure, and other damage. Sealants also help to improve the appearance of the pavement and provide a smoother driving surface.
Industrial Facilities
In industrial settings, sealants are used to fill gaps and joints in concrete floors, walls, and other structures. They help to prevent the infiltration of chemicals, water, and other contaminants that can cause damage to the structure. In facilities that deal with temperature fluctuations, such as refrigeration or processing plants, sealants are used to accommodate expansion and contraction.
Airport Runways and Taxiways
Sealants play a critical role in maintaining the integrity of runways and taxiways. They are used in expansion joints and cracks to prevent water infiltration, which can cause freezing and cracking. They also help in providing a smooth surface for aircraft operations, thus improving safety and performance.
Expansion Joint Sealants have various specifications based on the intended application. Knowledge about these specifications helps in making the right performance choice:
Movement Capability
Sealants are usually designed to accommodate a certain percentage of joint movement. This can be either +/-25% or +/-50%. This capability will depend on the type of joint application.
Shore A Hardness
Hardness is a critical property of sealant, as it will determine its elasticity and flexibility. It is measured using a Shore A durometer. For example, low-hardness sealants will provide greater flexibility and are suitable for surfaces that experience large movements. Hence, they are ideal for surfaces that deal with thermal expansion and contraction. High hardness sealants provide great resistance to pressure or mechanical wear. They are therefore suitable for surfaces that experience minimal movement.
Elastic Recovery
It is the ability of a sealant to return to its original form once the applied stress has been removed. High elastic recovery sealants are ideal for surfaces that experience frequent movement. This is because after expansion and contraction, they will return back to their original shape.
Application Temperature Range
This is the range of temperatures within which a sealant can be successfully applied and will cure under good conditions. Sealants with a broader temperature range can be used in more harsh and extreme weather conditions.
Chemical Resistance
Some expansion joint sealants are designed to withstand exposure to various chemicals, oils, and solvents. This is especially important in industrial settings where such environments are common.
Routine Inspections
It Is recommended that visual inspections be done frequently. This will help in identification of any signs of wear and tear, cracking, or displacement. In advance inspections, physical tests of the joints can be done to identify potential failures and defects. During inspections, note the date of application and the type of damage recorded. Indoor resting space with foldable chairs could be created while conducting the inspection.
Cleansing Procedures
Ensure that the joints are free from dirt, debris, and other foreign materials that could affect the sealant. Use appropriate tools or chemicals that will not damage the sealant itself. Thoroughly remove any old or failing sealant during maintenance.
Sealant Replacement
Depending on the normal wear and tear observed during inspections, replacement should be done as necessary. This can be reapplication or total replacement of the old sealant. Always consult the manufacturer’s specifications for guidelines on the reapplication of sealants.
Monitoring Joint Movement
Keep track of the movement of the joint as it occurs and ensure that the sealant used can accommodate this movement. If signs indicating that the joint is not accommodated appear, consult an engineer immediately.
Preventative Measures
Use the appropriate sealant for the given application to ensure proper maintenance. Ensure that the structure that has joints loaded on the sealants has proper drainage. Consider installation of expansion joint covers to minimize exposure to elements.
Determine the type of material
The common materials that construction have include concrete, metal, and masonry. For concrete surfaces, use a polyurethane or silicone-based expansion joint filler. In metal surfaces, consider using a sealant that will provide both corrosion and oxidation resistance. For masonry such as brick or stone surfaces, an acrylic latex sealant modified with silicone.
Appearance
Many manufacturers have paints that can match their expansion sealant. This means the sealant will be painted over to have the same texture and aesthetic value as the surface. A sealant that can be painted over is great for surfaces that have undergone a lot of wear and tear and are likely to experience cracking.
Determine the joint size
Measure the width and depth of the joint. Get the size of the sealant required. For wide joints, use a sealant with high extension characteristics. For narrow joints, use a sealant with low extension characteristics.
Movement capability
Sealants have different movement capabilities. Most sealants can accommodate between 25%-50% joint movement. Some advanced sealants can accommodate up to 100% in extreme cases. Choose the right sealant based on how much movement the expansion joint will typically experience.
Exposure conditions
Consider the environmental conditions of the surface where the sealant will be applied. Sealants intended for outdoor use should provide UV light, weather, and water exposure. Those intended for indoor use should be resistant to mildew, moisture, and mold.
Shore hardness sealants
Sealant hardness is measured on the Shore A scale. Low Shore A numbers have high flexibility. They are ideal for surfaces that will experience a lot of movements. High Shore A numbers have low elasticity. They are ideal for surfaces where minimal movement is experienced.
Ensure compatibility
Get an expansion joint sealant which is compatible with other caulk or sealant types used in the project. Ensure that the sealant is compatible with the substrate it is to be applied to.
A1. Concrete expansion joint sealant is specifically formulated to withstand the rigors of expansion and contraction, while caulk may not have the same level of flexibility, durability, or waterproofing properties.
A2. Expansion joint sealants fill the gaps between materials in construction, allowing for movement caused by temperature changes, settling, or vibrations while preventing water, air, and debris infiltration.
A3. A sealant is a material used to fill and close gaps or cracks, providing a protective barrier, while a joint refers to the space or separation between two building elements where the sealant is applied.
A4. Without sealant in expansion joints, movement between connected structures may cause cracking, shifting, and damage; further, moisture and debris infiltration could lead to corrosion, staining, or structural weakening.
