| dc.description.abstract | Hot-mix asphalt (HMA) has two primary ingredients: binder and aggregate. The asphalt binder is usually asphalt cement. The mix design system determines the correct proportion of asphalt cement and aggregate needed to produce an asphalt mix that has the properties and the characteristics to withstand the effects of traffic and the environment for many years. Viscosity graded asphalt cement AC-10 has been used in HMA binder by Directorate General of Highway, Ministry of Transportation and Communications (MOTC) for many years. During Summers, there are some ruts﹑bleeding and fat spots in the pavements. AC-10 material seems to be softer, less viscous for HMA binder in pavement constructions.
Climate can have a major impact on mix and pavement performance for a given pavement structure. The mean annual air temperature is from 22.3℃ to 25.0℃ in Taiwan. According to the Asphalt Institute Manual Series No. 2 (AI MS-2), AC-20(penetration graded asphalt cement 60-70 grade) material will be chosen for HMA binder in such hot climate like Taiwan.
In order to practice the new HMA binder such like AC-20, Directorate General of Highway, (MOTC) chooses No.1 Provincial Road 380k+000~381k+596 to pave the AC-20. By the evaluation, there are 6 times laboratory and in-situ tests in 2 years by the Materials Testing Laboratory, Directorate General of Highway, (MOTC). Such as the percent air voids, stability, deflection(the Benkelman Beam), rutting, Hi-Lo detector, profilograph and distress survey.
By the statistical testing of the results, there is an apparent difference in the strength of pavement structure between AC-10 and AC-20. In other words, AC-20 asphalt concrete pavement provides higher strength than AC-10 asphalt concrete pavement. It is a good strategy to choose AC-20 for HMA binder in Taiwan. Practice makes perfect. To sum up then, AC-20 asphalt concrete pavement can be widely put to use in Taiwan under management of Directorate General of Highway, (MOTC) and it is very helpful for Directorate General of Highway, (MOTC) to acquire favorable public impressions and raise highway construction quality up to pavement serviceability. | en_US |