Factors Influencing Adhesive Bonding Efficiency in ETICS Application.

Area of Science:

• Construction Materials Science
• Building Physics
• Adhesion Science

Background:

• Adhesive bonding is critical for External Thermal Insulation Composite Systems (ETICS).
• The ribbon-and-dab method is a common application technique.
• Understanding physical factors affecting bond strength is essential for system durability.

Purpose of the Study:

• To analyze physical factors influencing adhesive bonding efficiency in ETICS using the ribbon-and-dab method.
• To investigate the relationship between pressure distribution, adhesive layer thickness, and bond strength.
• To develop a model for predicting pressure attenuation in adhesive layers.

Main Methods:

• In situ observations, laboratory experiments (pull-off tests like CAST and DAST), and numerical modeling were employed.
• Pressure-mapping tests (PMAST) were used to analyze pressure distribution within adhesive dabs.
• Monte Carlo simulations were utilized to model radial pressure attenuation and variability.

Main Results:

• Increasing adhesive layer thickness from 10 mm to 20 mm drastically reduced bond strength (up to 86%) in the central area.
• Edge zones of thicker adhesive layers often exhibited no adhesion.
• Pressure-mapping revealed non-uniform pressure distribution, with higher pressures concentrated in specific zones.

Conclusions:

• Adhesive layer thickness is a critical factor affecting bond performance in ETICS.
• Increased thickness leads to reduced contact pressure and consequently lower bond strength.
• The developed decay function and simulation model provide insights into pressure attenuation and bonding performance prediction.