Effect of Coarse Aggregate Shape on Engineering Properties of Stone Mastic Asphalt Applied to Airport Pavements

10.6135/ijprt.org.tw/2013.6(5).595

Jian-Shiuh Chen；Wei-Chou Hsieh；Min-Chih Liao

Aggregate shape ； Stone mastic asphalt ； Rutting resistance

International Journal of Pavement Research and Technology

6卷5期（2013 / 09 / 01）

595 - 601

英文

Stone mastic asphalt (SMA) was developed in Germany during the 1960's as a durable asphalt mixture. In late 1990's, the Construction and Planning Agency brought the German asphalt mix technology to Taiwan. The initial interest in the use of SMA on highway pavements continued with the application to airport pavements. Laboratory work was conducted to refine the SMA design procedure in terms of coarse aggregate shape. Image evaluation provided quantitative indices such as geometric measurement and angle rotation of granular materials. The change in rotation angle of coarse aggregate was found to correlate well with the internal resistance of a SMA mix. SMA was shown to possess improved resistance to rutting and moisture damage if the engineering properties of coarse aggregate were under control. The requirements for flat and elongated particle were crucial to the engineering properties of SMA applied to airport pavements. Cubical particles were desirable for increased aggregate internal friction and improved rutting resistance. The particle index (PI) value of coarse aggregate significantly affected the engineering properties of a SMA mix. A high PI value indicated that the aggregate shape is likely to be cubical. The particle shape determined how aggregate was packed into a dense configuration and also determined the internal resistance of a mix. Of the four particle shapes evaluated, the cubical aggregate demonstrated the best rutting resistance. Flaky and/or elongated aggregate was shown to have lower compactibility and higher breakage.