Analysis and countermeasures of common quality defects in hot-melt road markings

1、 Common quality defects of hot-melt road markings

1.1 Coating surface contamination

Surface contamination of coatings is an inevitable issue for road markings. Generally speaking, external factors such as weather, construction, and internal factors such as hot-melt coating materials will all affect the degree of contamination on the coating surface. Among them, factors such as weather conditions, construction quality, and usage location have a significant impact on coating surface pollution. As a thermoplastic hot melt coating, when the temperature is too high, the coating is prone to softening and the surface adhesion will increase. Under conditions that are prone to adhesion and fouling, the coating surface will be contaminated. Especially in areas where vehicles frequently start, brake, and turn around at road intersections or stops. At the same time, the hot melt coating material is thermoplastic, and when it softens at high temperatures, the surface becomes sticky and the roughness increases, resulting in a corresponding decrease in brightness.

1.2 Coating discoloration

The main components of hot melt coatings include pigment fillers, resins, additives, reflective materials, etc. As organic substances, resins, additives, etc., it is inevitable to cause discoloration of the coating film after thermal cracking, which puts higher requirements on the heating temperature during construction. Meanwhile, the overheating of the preheated coating and the mixing of edge coke are also major reasons for the discoloration of the coating. The main reason for the discoloration of the coating is that the markings have been exposed to direct ultraviolet radiation for a long time, resulting in their color fading.

1.3 Poor nighttime reflective effect The nighttime reflective effect of hot melt coatings is influenced by multiple factors. Among them, the quality and performance factors of coating materials and reflective materials themselves, as well as factors such as construction equipment and skills, are also affected by environmental conditions and road conditions. Any one of the influencing factors may lead to poor reflective effect of the markings.

During the construction process, the fluidity and viscosity of the coating will affect the dispersion and fixation of reflective materials such as glass beads. If the coating is too hard, it will make the glass beads unstable, which will result in the glass beads being easily worn off by the wheels. If the coating is too soft, the glass beads are pressed into the coating, thereby failing to achieve the reflective effect of the glass beads. At the same time, the quality of glass beads is also an important factor affecting the reflective effect. Due to poor storage. Causing moisture, uneven drop, or mixing of debris in glass beads will directly affect the reflective effect.

In the study of reflective effects, the construction environment and conditions of road markings will have a certain impact on the reflective performance of the markings. If construction is carried out under strong wind conditions, it will cause glass beads to gather on one side, affecting the overall reflective effect. If the construction is carried out directly on old markings and uneven road surfaces, it will cause uneven coating film thickness, thereby affecting the fixation status of glass beads and affecting the reflective effect of road markings.

1.4 Peeling and peeling

Quality defects are common construction problems, and as one of the most serious consequences of quality defects, the harm of peeling cannot be underestimated. It will directly cause the marking to lose its marking function and also affect the beautification zone of the road environment. Generally speaking, the main reasons for peeling and peeling are defects in coating materials, construction conditions, and construction environment.

Among them, the phenomenon of cracking and peeling is relatively common, mainly due to the fact that the hot melt coating is a thermoplastic material that becomes rigid after cooling and is prone to peeling and peeling at the fracture site. At the same time, if construction is carried out directly on the old markings, it is also easy to cause peeling and peeling. The main reason is that the surface of the old marking film itself is generally relatively smooth, and peeling and peeling are also common when the construction conditions are not well understood.

At the same time, the construction conditions also have a significant impact on it. Poor cleaning during construction, insufficient dryness of the road surface, low construction temperature, and low temperature of the coating itself will directly affect the adhesion of the coating, leading to peeling and peeling.