Analysis of Fine Asphalt Concrete Mixture Gradations from Various Sources to Enhance Durability
In an effort to reduce the negative effects on our environment caused by the construction of vital economic infrastructure such as the roadway system, extending pavement service lives will help lessen the toll on the former. One of the factors that can influence the durability of asphalt mixtures, is the gradation. This thesis will look into the effect of fine aggregate dense gradations on asphalt mixture durability for sources from the state of Nevada. Based on the available literature, finer gradation asphalt mixes have lower air void content and therefore higher moisture damage resistance. This is because the finer aggregates tend to fill the voids that were otherwise not filled by the coarse aggregates. This will lead to enhanced durability because less water and air can penetrate the mix, leading to less oxidation and moisture damage. Finer gradations can also offer better cracking resistance due to the higher asphalt content and the lower air voids can create better cohesion in the mix. It was widely accepted that coarser mixes, such as SMA, provided better rutting resistance especially in heavy traffic conditions and higher temperatures due to the improved stone to stone contact which may act as a stronger aggregate skeleton for the mix. However, recently more DOTs have been shifting to finer gradation as studies have shown that they can have better rutting resistance. This research suggests there are a few factors to consider when designing an asphalt mixture, including the traffic loads and environmental conditions. However, a finer gradation can provide an overall improved moisture resistance and fatigue life so it should be considered carefully when designing asphalt mixtures. Therefore, a well-balanced mix design that can achieve the best rutting and cracking resistance is recommended to achieve the most ideal gradation that works best for the specific regions of Nevada.
Aggregate Gradations, Asphalt Mixture Design, Nevada DOT, Pavement Design, Pavement Engineering, Performance Testing
Networked Digital Library of Theses and Dissertations