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Road stud
Table of contents
Road stud
Common road stud
Solar road stud
Active tunnel road stud
Intelligent wireless road stud
Frequent problems regarding installation
Installation method of road stud
Frequent problems regarding road stud
Road stud
Road studs are usually used for railways and highways. Road stud (hereby refers to highway stud), also called raised road marker, belongs to a sort of traffic safety facility. It is installed in the middle of lane lines or yellow double-line for, through its retro reflection, reminding drivers to drive their vehicles along with the lanes. The specification of road studs is 100mm*100mm*20mm generally, and the height is not more than 25mm. Different reflectors are used including reflective sheets, reflective beads, LEDs and reflective films etc. The epoxy resin installation method is adopted generally for installation of road studs. Road studs can be divided into different types:
As per materials:
1. cast aluminum road stud; 2. plastic road stud; 3. ceramic road stud; 4. glass bead road stud; 5. reflective bead road stud (21-bead and 43-bead, which can be used for cast aluminum or plastic road studs).
As per functions: 1. common road stud; 2. solar road stud; 3. active tunnel road stud; 4. wireless road stud.
As per numbers of reflective sides: single-side road stud and double-side road stud.
Common road stud
(The compressive resistance of common road stud shall be more than 160KN in accordance with the requirement of the Ministry of Communications). Generally, cast aluminum road stud, plastic road stud, ceramic road stud and glass bead road stud are classified as common road studs. The detailed introductions of road studs as per functions are as follows.
1. Cast aluminum road stud
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Cast aluminum road stud
It can be divided into two types i.e. complete cast aluminum and cast aluminum casing road studs. The complete cast aluminum casing refers to the casing is made of metal completely with higher compressive resistance. Generally it is used in the middle of yellow double-line and called complete aluminum road stud. The cast aluminum casing refers to the casing is made of cast aluminum with filling materials. The cost and compressive resistance of such road studs are lower than those of complete cast aluminum casing ones and therefore they are called cast aluminum road stud or filled cast aluminum road stud generally.
2. Plastic road stud
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Plastic road stud
It can be divided into two types i.e. complete plastic and plastic casing road studs. Complete plastic casing refers to the casing is made through injection molding completely and the materials can be ABS, AS+ fiberglass and so on, and therefore the compressive resistance of which is higher. It is called as complete plastic road stud generally. The plastic casing refers to the casing is made of plastic with filling materials. The cost and compressive resistance of such road studs are lower than those of complete plastic ones and therefore they are called plastic road stud or filled plastic road stud generally.
3. Ceramic road stud The ceramic road stud, being made of cement pottery, round, was preferred in the past. It is not suggested since it is liable to be broken during transportation.
4. Glass bead road stud The glass bead road stud is made of glass and was preferred in the past. It is not suggested now since the installation is difficult.
5. Reflective bead road stud The reflector comprises of 21 or 43 high-luminance reflective beads. Swareflex is preferred for the manufacturer.
Solar road stud
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Solar road stud
(The compressive resistance of solar road stud shall be more than 100KN in accordance with the requirement of the Ministry of Communications).
The solar road stud featuring LED luminescence or passive luminescence is activated by solar panel as the Charger and battery or capacitor as the energy storage element. Its visual effect is better than that of common road stud. It can be divided into two types as per its energy storage element: solar road stud (battery) and solar road stud (capacitor). This product can be divided into two types as per different LED colors and voltages: 1. red and yellow; 2. white, blue and green etc.
Active tunnel road stud
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Active tunnel road stud
The active tunnel road stud, being more advanced than solar road stud, belongs to one of the traffic safety facilities. It is operated through the integrated control of controllers by taking solar panels or AC as the input source and twinkles or lights for a long time at the same time. The effect of the product is better than that of solar road stud. All road studs are connected with each other by conductors. The diameter controlled by each controller group can reach up to 1000m.
Intelligent wireless road stud
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Intelligent wireless road stud
The road stud can be operated through wireless signals from controller. No wire connection is provided for road studs and therefore the construction is easy. Interference with wireless signal sending and receiving is a technical difficulty. Technologies of road stud have been developing continuously and more types will be developed in the future.
Frequent problems regarding installation Since road studs are more and more favorable for high grade domestic highways and municipal roads, the quality and service life of road studs have become more and more important. During their practical application, damage to road studs and poor service life due to installation problems occur frequently. The author has put forward some available installation methods aiming at frequent installation problems concluded based on his years’ of experiences and hopes to pool the experiences with colleagues of the traffic circle.
The frequent problems during installation of road studs are as follows:
1. Installation of road studs on lane lines. Lane lines are resinous and adhered on the ground and therefore the adhesive force between which and the ground is limited. Provided road studs are installed a lane line, the impact force on the road studs will be transferred to the lane line, causing easy looseness of road studs and damage to the lane line.
2. Uneven installation locations of road studs. Uneven installation locations will directly cause uneven load-bearing of road studs since the load born is almost at the raised and sunken parts. Road studs are liable to damage under heavy vehicles.
3. Unclean installation locations of road studs. Firmness of road studs is determined by the adhesion among road stud, adhesive and the ground. If the installation locations are unclean, the dust will take most of the adhesive adhesion, causing loose road studs which are liable to shedding under extraneous force.
4. Lack or over usage of adhesive. Lack of adhesive will decrease the adhesion of road studs with the ground, causing poor service life of them; Redundant adhesive will seep out of road studs provided the adhesive is over used, causing poor reflection of reflective sheets of road studs.
5. Uneven applying of adhesive. When road studs are installed, the consumption of adhesive shall be available and applied evenly so that even load-bearing of road studs can be ensured and damage to road studs due to uneven load-bearing can be prevented.
6. Unavailable ambient temperature for preparation of epoxy resin adhesive. The epoxy resin adhesive is bi-component and can only be used after preparation of adhesive and solidifying agent under a certain proportion and even mixing. The epoxy resin adhesive is hard to mix evenly in winter, so it must be heated for softening before use.
7. Incorrect taking up of road studs. The two sides without reflective sheets shall be held when the road stud is taken up for preventing the reflective sheets from adhesive and poor effect of reflection.
8. Shallow and fine installation hole sites of road studs. The problem hereby is in relation to cast aluminum footed road studs mainly. Cast aluminum footed road studs have better impact resistance, compression resistance and longer service life since part of which is inserted into the ground, however, during the installation, the bottoms of road studs will not contact with the ground completely provided the hole sites are shallow and fine, causing poor firmness of adhesion.
9. Inadequate solidification time of adhesive after installation. After road studs are installed, the adhesive needs time to solidify for firm adhesion between road studs and the ground. It is suggested that 4 hours be used. However, practically, the isolation facilities are always removed within two hours after installation, so under this circumstance, the road studs might be deformed or even shed due to impact and rolling of vehicles.
Installation method of road stud
1. The arrangement of isolation facilities for installation is very important and during the whole dynamic construction, whether the road is under construction or used, all persons shall be within the scope isolation facilities. If the construction is performed on a used road, the proportion between safety supervisors and installers shall be 1:1. As for construction on unused road, the proportion between safety supervisors and installers shall be 1:3.
2. Even installation locations shall be ensured. As for curve and uneven road surfaces or surface with cracks, road finishing work shall be done in advance;
3. The installation locations shall be cleared with brushes and keep dry;
4. The adhesive as required shall be applied evenly on road studs;
5. When road studs are put at their installation locations closely, correct direction shall be ensured. The adhesive shall be cleared provided it is over used.
6. When footed cast aluminum road studs are used, the depth of hole sites shall be 1cm more than that of road stud foot and diameter, 2mm more than that of foot.
7. Road studs shall be checked after installation within two hours for ensuring that no reverse and oblique installations or deformation exist.
8. The isolation facilities shall be removed 4 hours after the installation.
Installation of road studs is not complicated, but the relative details shall be noted, which play a very important role for ensuring the quality and service life of road studs.
Frequent problems regarding road stud
Impactor of reflective sheet of road stud
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Impactor of reflective sheet of road stud
Poor impact resistance of reflective sheet At present, the key point for raised road markers is that the impact resistance of reflectors is poor. Over 80% of the products have such problem. Casings of most reflectors are welded through ultrasonic method as the process requires and therefore shedding and cracks of reflective sheets are inevitable, and the reflection effect will be affected due to inleakage of rain water on rainy days. Testing method: An impact test shall be performed for reflectors of road studs. After the white sheet is drawn out, use a 1KG steel ball to impact the surface of a road stud reflector under free fall, then dip it for luminance check. The luminance does not decrease if no water is leaked into the reflector. Poor compressive resistance The compressive resistance of road studs shall be more than 16t in accordance with the requirement of the Ministry of Communications, however, the compressive resistance of most road studs can not meet this requirement. Quick attenuation of luminance of reflective sheet The reflective sides of road studs are liable to be worn out by tyres with sand grains of roads. As for reflective sheets of single plastic road studs, the luminance will drop 50% within three months due to poor wear resistance. The transparent anti-wear coating method can be adopted for surfaces of road studs if their reflection effect is poor.