AQU™ Polymer Fiber is made of para-aramid, which has been proven to increase the strength, crack resistance, rut resistance, fatigue life, toughness and service life of any asphalt mixture.
Testing on AQU™ Polymer Fiber has produced results showing a 140% increase in crack resistance and 60% increase in rut resistance. Aramid has also been the subject of numerous U.S. and international asphalt performance studies over the past 15 years. Fiber additives for asphalt concrete have a history dating back more than 40 years, but it has been the recent advancements in materials and the way pavement researchers test and quantify performance that has confirmed the predictability and reliability of aramid for asphalt concrete pavements. The combination of historical and recent research, testing, and case studies demonstrate the active material in AQU™ Polymer Fiber significantly enhances asphalt concrete pavement performance.
Simply put, traditional asphalt concrete is made up of “rocks and glue.” The aggregate (rock) in asphalt concrete provides compressive strength and wearing resistance. However, because it’s a hard and smooth pavement, asphalt concrete is vulnerable to temperature changes. When cold, it has a tendency to become brittle and crack, and when warm/hot it has a tendency to soften and flow, which leads to rutting. Since aramid is a fibrous, tensile solid, its properties remain consistent whether it’s cold or hot. When the asphalt is cold, aramid fiber helps reduce the cracking effect of asphalt concrete by adding significant tensile strength. When the asphalt concrete is warm/hot, aramid fibers resist rutting because the fibers are imbedded and rooted into the asphalt to resist flow. AQU™ Fibers significantly increase the tensile and binding strength of asphalt concrete.
We have two different approaches to asphalt concrete pavement designs with AQU™ Fibers.
- Standard Practice – This method is simply using aramid fiber’s performance enhancements and applying them to your current asphalt concrete pavement design. If an agency wants to have longer lasting asphalt concrete pavement, it can simply add AQU™ Fiber to their mix. AQU™ Fiber can specifically be used to add extra reinforcement to busy intersections, bus lanes, loading areas and challenging road sections that have a history of cracking/rutting or failing prematurely.
When a street maintenance department uses AQU™ Fibers, it can reduce pavement sections from a 3-inch asphalt concrete overlay to a 2-inch asphalt concrete overlay without sacrificing performance. This will save you approximately 33% cost savings and allow the redeployment of resources into 33% more overlays in maintenance projects.
The reduction in thickness more than offsets the cost of AQU™ Fiber while enjoying increased performance and life.
- Modified Structural Numbers/Layer Coefficients — Depending upon which pavement design method is used, pavement engineers can design asphalt concrete pavement sections with aramid fiber by modifying their structural numbers or layer coefficients in design programs. For instance, if a pavement designer is using AASHTO, he/she can use an enhanced layer coefficient in the design program for the asphalt layout because the fiber-mixed asphalt has significantly higher performance characteristics. The pavement designer can then decide how to use the enhanced asphalt performance to produce a thinner asphalt, aggregate, or other layers to save costs, increase life, or a combination of both.
For batch plants the proper amount of AQU™ Polymer Fibers are put into the weigh hopper and mixed as usual. For drum plants, AQU™ Polymer Fibers are manually or mechanically fed onto the RAP belt, or blown into the RAP collar at the rate the drum is mixing asphalt concrete. AQU™ Polymer can be fed with different kinds of mechanical feeders that are easy to hook-up without plant modifications.
For an additional cost, Surface Tech can also provide third party mixing services performed by licensed and trained engineers to ensure uniform distribution. Pre- and post-mixing reports are done at the plant or in the field by a licensed engineer to ensure that the proper amount of AQU™ Polymer Fiber was added to the amount of asphalt concrete. AQU™ Polymer Fibers are pre-treated so that the fiber filament clips drop into the asphalt mixture and disperse uniformly with the mixing of a batch chamber or spinning of the drum chamber. The individual fibers are also visible upon inspection of fresh asphalt mix.
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