Structural Sealant is a neutral curing silicone sealant designed and tested for structural bonding assembly in glass curtain walls

Structural Sealant is a neutral curing silicone sealant designed and tested for structural bonding assembly in glass curtain walls. It offers excellent un-primed adhesion to most building substrates.

Structural adhesive has higher tear strength, elongation at break and tensile strength than weatherproof adhesive. It also has the ability to transmit alternating external forces without being displaced.

Strength

Structural Sealant transfer all load from glazing to aluminium frames and also prevent the glass from falling in case of a failure. That is why it is important to choose the right construction silicone sealant for your project.

Both assessment ways are based on simultaneous exposure of system test specimens to artificial weathering and complex mechanical loadings. This enables to detect the general mechanical response (e.g. a detailed exploration of visco-elasticity), maximum stress states, temperature and humidity sensibility and the individual system fingerprint.

The results of this study demonstrate that the first generation 2-part structural silicone sealant from the IFT Rosenheim facade successfully passes both ETAG durability criteria with flying colors. Among others, the residual tensile strength after all types of accelerated aging tests must still be more than 75% of the initial mechanical strength measured at 23 degC. Additionally, the resulting rupture surface of the cured sealant must be predominantly adhesive in nature.

Durability

Structural sealants are used in a dynamic building environment that is subject to movement in the form of expansion and compression. To avoid failure of the sealant and bond, it is important to evaluate, design for, and accommodate these movements.

A key factor in this is to be sure the sealant is compatible with the materials of construction it will be sealing to. This can be achieved by ensuring the correct primers are used and fully cured.

Durability assessment is often based on tensile and shear tests of cut-out small-scale specimens from system specimens exposed to simultaneous mechanical and climatic loading. However, this approach is limited and does not allow for a statistically significant durability assessment of the two structural sealants. Furthermore, discontinuous characterisations of the exposed specimens and sealant material (e.g. tensile, shear, hardness measurements) and visual examination of the system specimens after exposure are important for comprehensive durability assessment. These can supplement the continuous performance assessment results.

Weather Resistance

Structural silicone sealant is a weather resistant adhesive, and it holds up to sun (mainly UV) and rain for a long time. It also prevents humidity from entering a building, thus making it easier to control indoor temperature.

It is essential to have high-quality and durable products for construction projects. This is especially true in areas such as facades, where the integrity of the structure is dependent on a good bond between the structural elements and the glass curtain wall.

The aim of the present study was to carry out a mechanical characterisation of two structural sealants after combined climatic and mechanical loading. The results show that, despite 23+2 years of natural aging, the conventional mechanical properties of both systems in tensile and shear tests are still within the required limits according to ETAG 002-1.

Application

Structural Sealant can withstand large external forces and is suitable for the bonding of weight structures. It is also resistant to aging, fatigue and corrosion. It is also durable, easy to apply, and provides a strong, water-tight seal that prevents leakage of pressure, liquids, or condensation.

The mechanical behaviour of structural silicone bonding during combined mechanical and climatic exposure is characterised by analysing the conventional engineering parameters from tensile and shear tests of medium-scale system specimens cut from each test series. Moduli and dissipated energies show a characteristic decrease during the climatic exposure, which is attributed to stress relaxation of the sealant.

The results show that the stiffer structural sealant a of series A shows a higher modulus during combined mechanical and climatic exposure than that of the less stiff sealant b. This is reflected by the different damping capacity of the two systems. The rupture surfaces of small-scale specimens show notches and cracks on the accessible side of the sealant bead for both test series.