Obtains the coefficient of dynamic friction by measuring the force necessary to maintain constant the speed of a weight that is pushed on the pavement. The machine makes a programmable route on the pavement, drawing a graph with the measurements obtained. The sole of the device is of type 4S (STANDARD, SHOE SOLE, SIMULATING) made in the U.K. by RUBBER and PLASTICS RESEARCH ASSOCIATION
The test has been carried out following the method described in the draft of the ISO / D1S 10545 , which consists of measuring the coefficient of friction using a TORTUS device on the surface, registering the force that they oppose during its travel. these to the sliding of a standard rubber specimen of hardness IRHD 96 + -2, with properties and dimensions previously determined. The values provided by TORTUS are those of the friction coefficient expressed as the resistance that the tiles oppose to the sliding of the test piece on the surface, divided by the load applied on it. The test is carried out first on the dry surface, and then on it previously wetted with a solution of distilled water and a wetting agent.