At the VTI, a special machine for accelerated testing of pavement wear is being used to perform investigations under controlled conditions. Using the machine, a study has now been completed on two types of lightweight studs, one with a plastic body and the other of light metal. Tests using plastic studs have been performed at two speeds, 60 and 85 km/h, while the light metal stud has been tested only at the higher speed. With the exception of one case, test runs have been made on a dense asphalt concrete (AC) pavement with normal wear resistance. In one run, plastic studs were also tested on Stone Mastic Asphalt (SMA) pavements with high wear resistance. On both the wear-resistant and normally wear-resistant pavements, abrasion from the lightweight plastic studs was generally about half that from corresponding steel studs. However, the absolute wear level naturally differed according to the wear resistance of the particular pavement. For example, the most wear-resistant pavements in the tests, SMA pavements with very high quality aggregate demonstrated 3-5 times less abrasion than the "normal pavement" with locally obtained aggregate. Also abrasion from the light metal studs was considerably lower than from the conventional steel studs and even lower than from the somewhat lighter plastic studs. Light metal studs produced only about one third, 35%, as much wear as steel studs. The corresponding ratio between plastic and steel was 44%. The tests showed that speed is of great significance for pavement wear. Abrasion increased significantly at higher speed. Steel studs gave almost the double amount of wear at 85 km/h compared to 60 km/h. To obtain an idea of the wear-resistance of the studs, stud protrusion has also been measured. The decrease in protrusion was of the same order of size for plastic studs as for light metal and steel studs. Thus, the results do not indicate any significant difference in wear resistance between the various types of stud. The conclusion from the investigation is that the lightweight studs that have been tested reduce pavement wear by about half. The calculated cost of this wear could thereby be halved within a few years when these studs have replaced the conventional steel stud. (A).
Samenvatting