The construction of road hot-melt reflective paint is complicated for the construction of normal temperature marking paint. Due to the different construction methods, the special equipment used is also different. At present, there are two main types of equipment used for road marking: one is self-propelled, where the material and coating group are integrated, and the pressure spraying method is used; the other is a scraper. Hand push type, this method of construction is currently more common.
The hot-melt marking construction workers can be roughly divided into three groups, namely the road surface treatment group, the paint melting and dispersing group, and the marking coating group. During the construction, the road surface must be dry and dust-free. The temperature is generally 15t～30t. The temperature is too low, the coating is difficult, the adhesion to the ground is also poor, and the temperature is too high, especially on the asphalt pavement, the wheels and the lower hopper ( Alloy knife edge) sinks, which affects the quality of the gauge line.
The specific operations are as follows:
(L) The so-called pavement treatment team is the sanitation cleaner before construction. Dust and debris on the pavement will affect the quality of the hot-melt marking. Therefore, the road surface soil, floating dust and obstacles must be removed before construction, and then the stakeout work is started. Stakeout is to mark the wire, there are many ways, one is to use a rope to bounce the gray line (ie, bounce the line package). This method is fast and simple, but has high technical requirements for line marking personnel. Use experience to ensure that the wire is straight, easy to deviate, and the five-ash wire is easy to fall; the other is to use steel nails to pull the wire, which can ensure better wire curvature and straightness, but the progress is slower. During construction, it can be used flexibly according to specific conditions. The second step is to coat the primer on one side of the wire with a primer car. The spraying method is better, the width of the primer is uniform, the paint film is uniform, the material is saved, and the adhesion is also very good. With the artesian hand brush type, the amount of paint must be moderate, evenly applied, and no gaps or laces should be allowed. Dry for 5-10 minutes after coating, press and lift it with your fingers to make it into a silky shape. At this time, it can be considered that the road surface has been processed. Generally, the asphalt pavement can not use the primer, but it should be noted that the old road and the dusty asphalt pavement should also be coated with the primer to ensure that the marking has better adhesion.
(2) Paint melting and dispersion group. Put the coating (auxiliary) into the hot melt kettle, and control the temperature in the hot melt kettle between 180℃～210℃, and stir while melting. After melting and dispersing, in order to ensure the quality of hot-melt marking, inspection and testing before construction should be carried out. The inspection method is to sample a small amount of the paint in the kettle, paint it into a sheet (about 1.6mm thick), and let it cool naturally. After drying, bend it with your fingers. The best way to bend is when the slice breaks at 30-45. If it breaks just as hard as it is, or if it does not break if it is bent over and grasped, it is regarded as unqualified, and the additives must be adjusted. A large amount of additive makes the coating softer, and vice versa. If the marking is too brittle, road vibrations and car rolling will fall off; the marking is too soft, poor wear resistance, slow drying (or not drying), and the eyes tend to absorb dust, and the life of the marking will also not meet the requirements.
(3) Marking coating group. When the melted paint from the reaction kettle is put into the marking tank, it must be filtered with an iron screen. After loading, heat preservation is carried out (liquefied gas), and the lower hopper must be preheated. When marking, it depends on the wire coating, the traveling speed and the quality of the marking. The standard paint thickness is 1.5～1.7mm, and the marking length is about 180m. Pay attention to the temperature of the paint at all times when coating the marking. If the temperature is too high, the scattered reflective microbeads will sink into the paint, and there will be no reaction effect at the initial stage of the marking. If the temperature is too low, the paint dries too fast, the reflective micro-beads are floating and easy to be blown off by the wind, and the marking line also has no initial reflective effect. At this time, use the liquefied gas (open or extinguish) on the marking car to adjust the temperature. The suitable temperature of the coating during hot melt coating operation is roughly between 150°C and 180°C.
Precautions during the construction of hot-melt line marking: Do well in traffic evacuation and set up construction safety facilities before construction, as well as logistical services that also need to be considered. Because the hot-melt marking construction has a certain continuity, the front and back connections must be well coordinated. Generally, it is necessary to take turns to rest at noon. For example, it is troublesome to stop the machine to cool down and restart, and the paint will turn yellow and coke if the high temperature is too long. During the construction, the road surface treatment should be carried out first. If the primer is not dry, it will cause the primer on the whole line to catch fire due to the fire source under the marking car. In addition, sufficient attention should be paid to wounds and scalds during construction.