Can Thermoplastic Road Marking Be Constructed in Cold and Rainy Weather?
This is one of the most frequently asked questions by overseas road contractors. Many short-term marking failures such as cracking, peeling, bubbling and poor adhesion are not caused by paint quality, but by improper construction in unsuitable weather conditions. The answer is clear: thermoplastic road marking has strict requirements on temperature, humidity and pavement dryness. It cannot be constructed in rainy, snowy, frosty, or low-temperature environments blindly.
Thermoplastic marking relies on high-temperature melting and physical bonding with the pavement. Once affected by low temperature or water vapor, the curing speed, adhesion and internal structure of the coating will be severely damaged. Understanding weather construction standards can effectively avoid rework and improve the pass rate of road marking projects.
Why Is It Forbidden to Construct Thermoplastic Marking in Rainy Weather?
Many construction teams rush the project and construct in light rainy or humid weather, which leads to large-area bubbling and hollowing of the markings after completion. The core reason is water vapor inside the pavement. Thermoplastic paint is constructed at a high temperature of 180℃-220℃. When the high-temperature molten paint contacts the wet pavement, the residual moisture inside the road surface will instantly vaporize and expand, forming countless tiny air bubbles inside the marking layer.
After the markings cool down and solidify, these air bubbles cannot escape. With the rolling of vehicles and temperature changes, the coating will bulge, crack and peel off in a large area. In addition, the water film on the road surface will completely isolate the bonding force between the paint and the pavement, resulting in overall delamination of the markings. Therefore, rainy days, just after rain, and high humidity weather are all forbidden construction periods.
What Are the Problems of Low-Temperature Construction in Winter?
Low temperature is another major factor for thermoplastic marking failure. The standard construction ambient temperature is 5℃-45℃. When the temperature is lower than 5℃, the pavement temperature drops sharply, and the molten thermoplastic paint cools and solidifies in an instant after being laid on the road. The paint cannot fully infiltrate and form effective occlusion with the pavement, resulting in extremely low adhesion.
Moreover, low-temperature construction will make the thermoplastic coating brittle. Although the surface looks normal, it is prone to irregular cracking and block falling after encountering cold wind, vehicle vibration and temperature difference changes. Even if high-quality paint is used, the service life will be shortened by more than half if constructed in ultra-low temperature environments.
What Weather Conditions Are Suitable for Thermoplastic Road Marking?
For qualified long-life thermoplastic markings, construction must follow strict weather standards. The ambient temperature should be controlled between 10℃ and 35℃, which is the most stable temperature range for paint melting, paving and curing. The air humidity should be lower than 85%, and the pavement must be completely dry without accumulated water, frost, dew and dust.
In tropical high-temperature seasons, avoid construction at noon with strong ultraviolet radiation to prevent rapid surface aging of the coating. In dry and windy weather, strengthen pavement dust cleaning to avoid floating dust affecting bonding. Only by matching the correct weather environment can the thermoplastic marking give full play to its wear resistance, adhesion and reflective performance.
How to Remedy Failed Markings Caused by Bad Weather Construction?
If bubbling, peeling and cracking problems have occurred due to rainy or low-temperature construction, partial repair is not recommended. The hidden danger of water vapor and poor bonding exists in the whole marking area. It is necessary to completely remove the failed old markings, polish the pavement again, and carry out new construction after the weather clears and the pavement is completely dry and warm.
For concrete pavement affected by humid weather, it is necessary to re-brush the primer after the base layer is completely dry to ensure secondary bonding firmness, so as to avoid repeated failure of the repaired markings.
Summary
Thermoplastic road marking is highly sensitive to weather and pavement environment. Rainy days, high humidity, low temperature and frosty weather are all unsuitable for construction. Adhering to standard weather construction conditions is the key to ensure long service life and stable performance of road markings, and also an important standard for standardized road engineering construction.
