(Repost) The Economic Daily News | road marking tape to make roads greener and safer
Time: 2022-12-09 / View: 622 times
Driving safety is inseparable from road traffic signs and markings. Road traffic signs are traffic safety facilities composed of all kinds of lines, arrows, words, elevation marks, protruding signs and contour marks on the road surface. It is an important part of highway construction and one of the important traffic engineering facilities to ensure traffic safety and improve road service quality. The figures show that the correlation rate between road traffic marking and accidents reaches 70%, and reasonable road marking with good performance can increase the transportation capacity by 30%.
In the past, the traditional road traffic signs were marked with hot melt marking paint. Now there is a better new road marking product - road marking tape can be replaced. Recently, by Tongji University Integrated Traffic information and control Engineering Department doctoral supervisor, associate professor Peng Yichuan led the "road marking tape road performance research" project, after eight months of work and tests, passed the expert review. This issue makes up the blank of the studies in the field of road marking tape in our country's transportation infrastructure, and provides the foundation for the research of road marking tape in road traffic safety management. So as to provide reference for the engineering practices of road marking tape. Reduce or avoid the occurrence of traffic accidents.
As a new type of marking tape, road marking tape has been widely used in Germany, France, America, Japan and other countries. Compared with the marking paint, road marking tape has made great progress in the production process and road performance. It not only improves some shortcomings of the marking coating itself well, but also plays more advantages, and has a good application prospect.
Professor Peng's research group showed in the comparison test of the recognition performance of road marking tape and hot melt marking that the recognition performance of road marking tape was significantly better than that of traditional hot melt marking. There is no significant difference in the visual recognition performance between white hot-melt marking tape and yellow preformed marking line when there is strong sunlight irradiation during the day, but at night, the visual recognition performance of road marking tape is significantly improved compared with that of traditional hot-melt marking tape. Therefore, when the surrounding background light is weak or completely dark, it is recommended to use road marking tape, which can improve the driver's visual recognition performance and improve the driving safety. Among the different types of marking lines compared in the test, white road marking tape has the best apparent recognition performance, which has the most significant improvement compared with traditional white road marking tape, followed by yellow road marking tape, white hot melt marking and yellow hot melt marking.
Durability comparison shows that road marking tape has certain durability. In the comparison of removing coating modification, it is found that road marking tape adopts specially equipped pressure sensitive adhesive at the bottom to bond with the road surface. Therefore, the work to be done in removing and modifying the marking tape is only to destroy the pressure sensitive adhesive layer at the bottom, and there is no need to deal with the tire base. After destroying the adhesive layer, the tire base can be easily separated from the road surface. And the damage will not cause damage to the road surface and will not leave obvious marks on the road surface. The paint marking is cured and bonded to the road surface, which is mainly composed of a coating layer after curing, and the hardening flexibility of the coating after curing is very low, so the paint marking must be destroyed during the removal of the entire coating layer, which makes the marking and the road surface peel, not only the construction efficiency is low, but also brings certain limitations and negative effects. This shows that the preformed marking line has better removal coating modification.
It is reported that the amount of hot melt marking in China accounts for more than 90% of the total marking line, while there are more heavy metals in domestic road marking coatings, including arsenic, chromium, zinc, lead, phosphorus, copper, mercury, manganese, nickel and other heavy metals, these heavy metals can not be basically decomposed and degraded, and will remain in the environment. And the process of hot melt marking will also produce a lot of carbon dioxide. According to estimates, every 1 square meter of hot melt marking needs to consume about 0.6 kg of liquefied petroleum gas fuel, assuming that the annual hot melt road marking area is 13.07 million square meters, converted into standard coal (1 kg of liquefied petroleum gas combustion value =1.72 kg of standard coal), the annual hot melt road traffic marking needs to consume nearly 13.5 million kg of standard coal. According to the recommended value of the National Development and Reform Commission, a ton of standard coal can produce 2.4567 tons of carbon dioxide emissions, so when using hot melt line, it needs to emit 33,138 tons of carbon dioxide to the atmosphere.
The construction process of hot melt marking will also consume a lot of energy, including the melting process, the cleaning and drying of the road surface in the marking area before the marking reference line, as well as the serious environmental pollution of water resources, soil and air caused by the marking and cleaning and modification of the marking line. There are many environmental problems such as heavy metals, carbon dioxide emissions, dust and noise pollution. road marking tape mainly uses rubber pressure sensitive adhesive and resin pressure sensitive adhesive. Hot melt coating process is mostly used for rubber production, and solvent or water-based coating process is generally used for resin production. Resin type pressure sensitive adhesive is changing from solvent to water-based, mainly represented by acrylate pressure sensitive adhesive, with high initial adhesion, good transparency, good aging resistance, wide bonding surface, non-toxic and non-combustible advantages and low cost, safe operation, no pollution, water-based environmental protection products.
On the other hand, the marking belt is set on the road surface, not only to withstand the sun and rain, wind, frost and snow, but also to resist the impact of various vehicle loads. Therefore, the performance of road marking in complex road conditions is a very important performance. The research group also conducted relevant tests and comparisons on the performance of road marking according to different road environmental conditions and stress conditions, including water resistance, alkali resistance, wear resistance, skid resistance, cohesiveness, compressive resistance, durability, removal coating modification, etc.
The experimental results show that road marking tape can satisfy the water resistance and alkaline resistance well. In terms of skid resistance is more prominent. In the wear resistance test, by recording the weight difference between road marking tape and hot melt marking line after friction in the automatic rutting tester at the same ambient temperature, it is found that the weight loss value of road marking tape is not only 25% less than that of hot melt marking line. That is, the wear resistance of road marking tape is better, and the wear resistance of road marking tape also meets the standard provisions - the friction coefficient of the marking line after the new marking is between 0.6 and 0.8. The adhesive test shows that road marking tape has high adhesive property. In the test of compressive strength, a pressure testing machine was used to measure it. The final test result showed that the compressive strength of white road marking tape was 23.2MPa and that of yellow road marking tape was 23.6MPa, which was much higher than the standard of compressive strength stipulated in the code ≥12MPa. It is also higher than the 21MPa hot-melt marking line tested, that is, road marking tape has a stronger ability to resist permanent deformation of the marking line caused by vehicle axle load.
Another advantage is that the pre-forming of road marking tape is carried out separately from the construction. The pre-forming process does not need to be completed at the construction site, and spraying machinery and hot melt machinery are not required during laying. The ground can be pasted directly after gluing. The steps are simple, the personnel requirements are less, and because of the special structure of the marking line, it is completely possible to use manual or special tools to pull and peel during removal, which reduces the noise generated in the construction process to a certain extent, and hardly generates additional dust. Compared with other types of marking tape, during the laying process, road marking tape only needs to provide necessary adhesive force on the road surface to make it fixed, without heating and melting process. This construction method almost avoids volatilization of harmful compounds and carbon emission. Since the environmental performance of road marking tape is much better than that of hot melt marking, from the perspective of environmental protection, experts suggest vigorously promoting the laying of pre-formed marking.Author: Zhu Huichun
Editor: Zeng Shiyang
Editor: Xu Yuezhi
Article transferred from the Economic Daily News client
