Aggregate polish value and its consideration in skid prediction models developed in Argentina

In 1999, asphalt mixes with special characteristics have begun to be used in Argentina, especially open graded mixes with polymer modified asphalt and low thickness, SMA and F10 of Spanish Specifications, using granitic aggregates. Because in Argentina there were no experiences about these mix types from the point of view of skid resistance, since the beginning of construction a surveillance program have begun. Aggregates were tested using Accelerated Polishing, Micro Deval and Los Angeles tests. There were found that Polish Stone Value results (PSV) of Argentine granitic aggregates are low, with values around 40, because of that, surveillance program was followed with more attention. A test section evolution of 4.4 Km and 5 lanes with F10 surface mix on one of highest traffic of Argentina was followed. Tests were done on left track of each lane, two lanes of light traffic, and two lanes of heavy traffic. Test section was analyzed in sectors of 1 Km. Friction coefficient was measure using British Pendulum Tester, and macrotexture was measured using Sand Patch method. As a result was developed a skid prediction model that considers PSV, traffic volume and the age in service, as parameters. Additionally, on PSV test, friction was measured before and after polishing. Results indicated that PSV obtained before test is similar to the initial value of skid model, which is valid after the initial period of two month under traffic.