The excellent anti-fatigue performance of silicone elastic coating in bridge expansion joints is mainly due to its unique molecular structure and environmental adaptability, as shown below:

1. Molecular structure and anti-fatigue mechanism
‌Elastic recovery ability‌
The main chain of silicone coating with silicon oxygen bond (-Si-O-Si-) gives it high flexibility and deformation recovery, which can withstand repeated expansion and contraction deformation caused by temperature changes and vehicle loads of bridges, and effectively resist more than 20 million fatigue cycles‌. Its molecular chain can undergo reversible deformation under stress to avoid cracking and failure caused by accumulated plastic deformation‌.

‌Wide temperature range stability‌
In the extreme temperature range of -80℃ to 250℃, silicone coating still maintains elasticity, avoiding low-temperature brittle cracking or high-temperature softening (such as modified phenyl silicone resin with high temperature resistance of more than 300℃). This feature significantly reduces material fatigue damage caused by freeze-thaw cycles or seasonal temperature differences‌.

2. Advantages of Engineering Applications
‌Dynamic load adaptability‌
Through the coordinated design of the crossbeam and the displacement box, the silicone coating can disperse the impact vibration during vehicle passage and reduce stress concentration. For example, the expansion joint of the Runyang Bridge adopts a displacement control spring and a sliding support structure, which greatly extends the life of vulnerable parts.

‌Durability and environmental resistance‌
‌Weather resistance‌: The ultraviolet absorption rate of silicone resin exceeds 90%, and the gloss retention rate after 20 years is >85%, which is much higher than that of ordinary materials, preventing the elasticity from decreasing due to aging.
‌Waterproof and anti-corrosion‌: Low water absorption (<0.3%) and chemical inertness effectively block moisture, salt spray and acid rain erosion, and avoid structural fatigue caused by steel corrosion and concrete spalling.
‌Environmental protection‌: Low VOC emissions meet green building standards and reduce the negative impact of environmental factors on material performance.