Structural Sealant

Structural Sealant is an adhesive that has a large bearing capacity and is often used to bond structural components together. This type of adhesive is very durable and can withstand extreme temperatures.

Structural sealants are usually used in structural glazing applications as well as on building joint structural components that require a high bearing capacity. They are also highly resistant to UV and weathering.

Strength

Structural Sealant is a durable, high-strength, adhesive that can combine and connect structural components. It has the capacity to transfer a large number of forces and is generally used for building joints that require large bearing capacity and a long service life.

Stiffness of the material is determined by its modulus of elasticity, which can also be measured in terms of tensile strength and tear strength. The modulus of elasticity is important for determining the durability, flexibility, and weather resistance of a material.

In addition, a sealant’s strength is influenced by its temperature properties. Temperature-induced variations can affect both the mechanical and bonding strengths of a sealant. As a result, the Initial Mechanical Strength tests (ETAG 002-1) stipulate that the mean tensile and shear strength values at -20 degC and +80 degC must not drop below 75% of their corresponding values observed at +23 degC.

The Residual Strength test aims to evaluate the strength of a sealant after exposure to natural aging and is based on two criteria: The residual tensile strength must still equal or exceed 75% of its initial strength and the failure mode after aging must be >90% cohesive in nature. This test is performed at various temperatures, so the results of this study are limited.

Durability testing based on small-scale specimens is a method of assessing the performance of building joint sealants and is considered a valid alternative to field testing. It enables a quantitative analysis of the effects of ageing and fatigue on the sealing properties of sealant systems in the laboratory.

This type of laboratory testing is a key aspect for establishing the safety of structural silicone sealants. The climatic loading function of the laboratory apparatus is capable of generating a large number of stress levels and load cycles, and therefore allows for the detailed exploration of the general mechanical response of a sealant system.

In addition to a detailed examination of the swelling dynamically induced force paths, such a research approach can also yield indications on the hardness and damping capacity of the joint during climatic and combined loading. A comparison of the hardness results of a sealant bead that was only exposed to climatic loading and a silicone joint subjected to combined loading is shown in Figure 13 for complementing the interpretation of the tensile and shear tests.

Durability

Structural Sealant is a type of sealant that can be applied in contact with other construction materials to form a structural bond. It can also be used to seal the openings of windows and doors in residential and commercial buildings.

When choosing a sealant for a specific application, it is important to understand its durability. Durability refers to the ability of a sealant Structural Sealant to resist alternating external forces without deteriorating or breaking. This is achieved through the use of the correct surface preparation and application methods, as well as proper sealing.

The durability of structural sealant can be evaluated using a variety of test methods. These include initial mechanical strength tests and durability tests. In addition, it is important to consider compatibility with other materials of construction, including other sealants and substrates.

In the initial mechanical strength tests, the sealant’s strength is measured at different temperatures and in a range of tensile and shear forces. This is done to ensure that the sealant meets the minimum requirements set by ETAG 002-1.

To conduct these tests, the sealant was exposed to artificial weathering and a complex, multiaxial mechanical loading function, which was based on a mechanical loading device that simulated combined mechanical and weathering loading. Each system test specimen was subjected to this process and a control sample was also exposed only to weathering for reference purposes.

Once the durability tests were completed, the sealant was water jetted into small-scale specimens for mechanical characterisation. These were then tested for their tensile and shear strengths at T = 20 degC and strain rate.

The results from the tensile and shear tests show that both structural sealants met the initial mechanical strength requirements. However, the 2nd generation sealant had better performance than the 1st generation sealant. It passed the criterion for residual tensile strength, while the 1st generation sealant failed this requirement when exposed to simultaneous weathering and enforced movement.

The new methodology was developed in partnership with the Federal Institute for Materials Research Berlin/Germany (BAM). This method is based on simultaneously exposing system test specimens to artificial weathering and complex, multiaxial mechanical loadings. During this test, the 2nd generation sealant showed only marginal loss of adhesion at the specimen corners, while the 1st generation sealant suffered more extensive interfacial failure.

Flexibility

Structural Sealant is a type of adhesive that can connect and combine structural components. These include glass, window frames, and stone, to name a few examples. It is commonly used in structural Structural Sealant building joint components that need a high bearing capacity and long service life.

Compared to weather sealants, structural adhesives have more strength and resistance to tear. It also has higher elasticity, which allows for the movement of bonded material. However, if a sealant is subjected to a lot of force, it can be damaged.

As with all construction materials, it is important to choose a sealant that will be compatible with the substrates in an application. Typically, a manufacturer should be able to provide a compatibility test.

A durability test is a specialized testing method that evaluates the ability of a sealant to withstand climatic conditions and mechanical loads. Durability tests involve repeated exposure of sealant joints to a variety of weathering and loading cycles.

Durability tests often include destructive tensile and shear tests at different temperatures to evaluate the bonding strength. They must meet the requirements set out in ETAG 002-1: Initial Mechanical Strength, Residual Strength, and Failure Mode After Aging.

Both tensile and shear tests are conducted on small-scale specimens that represent the sealant joint. These are then tested at a range of temperatures (-20 degC to +80 degC) for the initial mechanical strength and failure mode after aging.

As a result, the tensile and shear strength values measured at -20 degC and +80 degC must not drop below 75% of their corresponding initial value measured at 23 degC. Additionally, the sealant must rupture after aging in a cohesive failure mode that is greater than 90%. This is because the temperature-induced changes in the polymer chemistry can impact the initial mechanical strength and bonding strength of a sealant.

Weather Resistance

Weather resistance is a term used to describe the ability of a sealant to withstand certain types of weather conditions. These conditions include rain, snow, wind, and acid rain. It is important for a sealant to be able to withstand these factors, so that it can function properly when the weather gets bad.

A good example of this is structural silicone sealant. This type of sealant has high tear strength, elongation at break, and tensile strength. It also has a high modulus of elasticity. This makes it an excellent choice for bonding weight structures.

Another interesting factor related to Structural Sealant is its ability to withstand weathering and UV exposure. This is especially true for sealants used in curtain walls or insulating glass. It can be difficult for sealants to withstand these factors without a protective coat of paint, so it is important to select a sealant that has high resistance to both.

To determine the weather resistance of a sealant, it must be tested at different temperatures to see how it performs. This can be done using a temperature-compensated strain sensor. This is particularly useful if the weathering cycle involves a wide range of ambient temperatures.

To better understand the weather resistance of a sealant, researchers tested it against two common sealants in a durability test that combined mechanical loading with weather cycling. This included tensile and shear tests of small-scale system specimens, as well as hardness measurements and visual inspection of the systems after exposure.