Crack problem of the thermoplastic paint

2012-06-11 10:17:59

1. If work in the cold winter, the coating will shrink and will produce an internal stress. When the Internal stress concentrates together, the pavement is easy to crack. The crack is related with the construction season, paint quality and the pavement conditions. Especially the new cement road surface, there are fragile mortar layer, curing membrane. It is easy to crack.
Solution: Try to avoid working in the cold winter. Reasonable to use the thermoplastic paint, choose suitable paint ratio in different season. For the new cement road, the maintenance time should over 2 weeks and clean the fragile mortar layer and curing membrane before construction.

2. Reflective crack caused by roadbed crack.
The crack caused by roadbed material’s expansion or contraction, or the crack caused by the non-uniform sinking of road surface.
Solution: Under such situation, it is difficult to solve. Need to enhance the roadbed construction quality.

3. Crack caused by road surface softening. In summer, sometimes the local temperature will exceeds 40℃ and the bituminous pavement will exceeds 60℃ under the sun shining fiercely. The bituminous pavement will become soft. At the same time, the paint is relatively hard than the road surface. It is easy to crack when the wheels pass it.
Solution: Choose the suitable paint formula ratio and match well to the pavement’s hardness and softness.

4. The coating surface crack is irregular reticular crack appearing on coating surface after construction. This kind of crack is comparatively shallow, but it often further develops to aging crack on this base, making the coating damaged. Resins and additives with good compatibility should be chosen firstly to prevent coating surface from cracking, and construction temperature needs be paid attention to control.

5. Crack appears due to marking line ageing. The deterioration of coating surface material and natural weathering makes marking line crack. Ageing crack is also owing to the reason that marking paint is exposed on the road for long, withstanding sun and rain of four seasons, day and night temperature differences, temperature changes between seasons, ultraviolet radiation and suffering from periodic expansion and contraction. To choose suitable marking paint is a necessary way to start with to prevent coating from ageing in advance. During marking construction, temperature should be controlled strictly and the pre-construction treating quality of road surface should be ensured to prevent blistering

6. Millipore and blistering is due to that the air, moisture or wet primer in road hole expands or gasifies under the high temperature action of paint. Blistering is caused by expanding air jacking up coating; millipore is the hole that left from expanding gas wearing through coating, and it is a common fault of coating. The probability of millipore and blistering appearing on wet surface increase is the result of that the road millipore is filled with moisture and humidity. High temperature paint makes moisture remaining in the millipore gasify, expand and form into millipore and blister; the primer contains some ingredients with low boiling points and it is not easy to dry. When wet primer remaining in the hole comes across high-temperature paint, volatile matter will gasify and expand rapidly and form into primer millipore blister. Millipore and blister not only affects marking line appearance, but also reduces areas that coating and road surface joints together, influencing seriously adhesiveness and service life of paint. Thus, paint kind with good liquidity should be chosen firstly. The road surface should be ensured to dry, and adequate sunshine is needed before construction after raining. Primer that dries quickly should be chosen, and at the time of controlling strictly construction temperature, the environment temperature coordination should also be paid attention.


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