ABSTRACT
The paper presents the comparison of friction coefficient results obtained from two types of dynamic devices: SRT-3 (Skid Resistance Tester) and TWO (Traction Watcher One), which are used to evaluate the skid resistance of national road pavements in Poland. The SRT-3 device operates with the locked wheel, equivalent to 100% slip ratio. The TWO is one of the devices which measures longitudinal force with low slip ratio, which for this particular device is 17.8%. The comparative measurements were carried out on 11 test sections. In order to obtain information about the texture of their surface, stationary devices were used. Macrotexture was characterised by the MPD (Mean Profile Depth) parameter obtained through CTM (Circular Tester Meter) measurements. Microtexture was estimated using the coefficient of friction DFT20 at a slip speed of 20 kph using a DFT (Dynamic Friction Tester) device. This has been proved by the functional relationship between the friction coefficient obtained from the individual dynamic device and the parameter describing the macrotexture and microtexture. A very good linear relationship between friction coefficient obtained from measurements using SRT-3 and DFT at all tested speeds was observed. The SRT-3 is sensitive to microtexture changes in the pavement but not to macrotexture. Friction coefficients obtained from TWO measurements at the test speed 30 kph is more sensitive to microtexture than macrotexture, but at the test speed of 60 and 90 kph it depends both on macrotexture and microtexture. It is caused by type of measured tyre. The SRT-3 is equipped with a ribbed tyre while the TWO has a smooth tyre. In addition, the need to implement stationary devices CTM and DFT as reference devices determining parameters related to texture, for comparative tests of dynamic devices.
Disclosure statement
No potential conflict of interest was reported by the authors.
ORCID
Marta Wasilewska http://orcid.org/0000-0001-6834-5206
Wladyslaw Gardziejczyk http://orcid.org/0000-0002-9130-3773
Pawel Gierasimiuk http://orcid.org/0000-0003-4681-570X