Unsaturated polyester resin has a relative density ranging from approximately 1.11 to 1.20, and it exhibits significant volume shrinkage during the curing process. Once cured, the resin demonstrates several notable physical properties:
(1) Heat resistance. Most unsaturated polyester resins have a heat distortion temperature between 50°C and 60°C. However, certain types with enhanced thermal stability can withstand temperatures up to 120°C. The linear thermal expansion coefficient (α1) typically falls within the range of (130 to 150) × 10â»â¶ °Câ»Â¹.
(2) Mechanical properties. These resins are known for their excellent mechanical strength, including high tensile, flexural, and compressive strength. This makes them suitable for structural applications where durability is important.
(3) Chemical resistance. Unsaturated polyester resins offer good resistance to water, dilute acids, and dilute bases. However, they tend to perform poorly when exposed to organic solvents. Their chemical resistance can vary significantly depending on the specific chemical structure and the type of cross-linking present in the polymer network.
(4) Dielectric properties. The resin exhibits favorable dielectric characteristics, making it useful in electrical insulation applications. It maintains a low dielectric constant and good insulating properties under normal operating conditions.
In summary, unsaturated polyester resins are versatile materials with a balance of mechanical, thermal, and chemical properties. While they may not be ideal for all environments, especially those involving harsh chemicals or extreme temperatures, they remain widely used in various industrial and commercial applications due to their cost-effectiveness and ease of processing.
The segment assembly formwork system is a new type of non-standard mechanical equipment applied to prefabricated cantilever assembly segment beams.
Through the analysis and demonstration of segment assembly technology at home and abroad, combined with previous experience in the design, production and construction of bridge formwork, after BY1203 and BY1306, the BY1507 automatic segment box girder prefabrication system was developed and launched. The segmental assembly template includes five parts: outer mold system, bottom mold system, blocking system (fixed end mold and mobile end mold), inner mold system and bottom mold trolley. The advantages of this method are that it occupies a small area, is easy to operate, is relatively small due to terrain restrictions, is relatively convenient to arrange beam fields, and has a high utilization rate of pedestals and templates.
Segmental Formwork,Assembly Formwork,precast concrete formwork,concrete shuttering
Anshan Lijian Engineering Group Co. LTD , https://www.lijianformwork.com