Author: Site Editor Publish Time: 2024-02-27 Origin: Site
In the building and construction industry, sealants are employed to connect and join the various parts and materials to the main structure and to themselves. They help commercial and residential buildings perform better by sealing out water, humidity, UV and more.
No sealant type is superior or inferior - it all comes to evaluating performance properties and developing the best suitable sealant to achieve desired results in the final application. Find out what are the important points to consider while developing construction sealants.
The building and construction industry employs multiple materials, like metals, concrete, etc. as well as many prefabricated parts, such as:
Sandwich panels
Windows and doors (made of metals, wood, PVC, etc.)
Partitions (often made of plasterboard)
Prefabricated concrete slabs for floors and exterior walls, etc.
Sealants are employed to connect and join the various parts and materials to the main structure and to themselves. They help in closing the gaps between the elements and surfaces of the construction and thus, prevent fluids and other substances from passing through surfaces and mechanical joints.
Sealants serve the following basic functions in the building and construction industry:
Filling the gap between two or more components
Providing a protective impermeable barrier, through which substances cannot pass
Maintaining their sealing properties through their expected lifetime, under the service conditions and environments for which they are specified
Also, another important requirement for sealing compounds is the high flexibility in order to tolerate movements between different materials used. These movements can happen due to:
Expansion or shrinkage because of thermal variations,
Dimensional variations due to variations of moisture content,
Deflections under loads,
Wind pressure, etc.
Various Types of Movements of the Joints and Sealants
These movements usually occur due to the different thermal coefficients of expansion of materials as shown in the table below.
| Material | Coefficient of Linear Expansion (m/m-°C x 10-6) |
| Clay, masonry (Brick, clay or shale) | |
| Brick, fire clay | 5 to 6 |
| Tile, clay or shale | 6.0 |
| Tile, fire clay Material | 4.5 |
| Concrete | |
| Gravel aggregate | 10.0 |
| Lightweight structural | 8.1 |
| Concrete, masonry | |
| Cinder aggregate | 5.6 |
| Dense aggregate | 9.4 |
| Expanded-shale aggregate | 7.7 |
| Expanded-slag aggregate | 8.3 |
| Volcanic pumice & aggregate | 7.4 |
| Cellular concrete | 11.0 |
| Metals | |
| Aluminum | 23.8 |
| Brass, red 230 | 18.6 |
| Copper | 16.5 |
| Iron | |
| Cast gray | 10.6 |
| Wrought | 13.3 |
| Lead, common | 29.3 |
| Monel | 14.0 |
| Stainless steel | |
| Type 302, 304 | 17.0 |
| Structural steel | 11.5 |
| Zinc | 36.0 |
| Glass, plate | 8.0 |
| Plaster | |
| Gypsum aggregate | 13.7 |
| Plasterboard | 12.0 |
| Plastics, composites | |
| Acrylics | 80.0 |
| Lexan® (Polycarbonate) | 67.0 |
| Flexiglas® | 70.0 |
| Polyesters, glass reinforced | 18-25 |
| PVC | 59.0 |
| Natural stones | |
| Granite | 8.0 |
| Limestone | 6.5 |
| Marble | 13.0 |
| Basalt | 9.0 |
Therefore, to achieve the desired performance & functions, it is necessary to match the most suitable sealant to the substrate materials that will be joined, i.e. one that will have adequate bonding properties and be flexible enough to tolerate anticipated movement, and so on.
