Asphalt Mix Designs

Quality is critical and what most of us aim for. The quality of the materials plays a big part in the longevity of use and cost-efficiency. As for asphalt pavement, the quality greatly lies on the asphalt mix design. Asphalt mix design is where mixing the right amount of correct aggregates take place to ensure temperature-resistance, fatigue-resistance, durability, and skid resistance, among others. There is a standard set of parameters for each of the aggregates.

The key to the right mixture is understanding how much of each of these aggregates are proven to produce utmost performance. Laboratory-made asphalt mix is calibrated and made under controlled conditions however the aggregates will still vary from time to time depending on where it is manufactured therefore understanding its properties are really important. The following are the parameters to watch out for: air voids, voids in mineral aggregate, voids filled with asphalt, and dust proportion. For one, air voids determine the durability of the mix. A certain amount of air void is needed to allow further compaction and slight expansion of the binder due to temperature rise.

In an article featured in Asphalt Magazine, four tips in controlling the asphalt mix designs in the laboratory and field were discussed. They write: “The air voids are the small pockets of air between the asphalt-coated aggregate particles in the asphalt mixture. A certain amount of air voids is required in the asphalt mix to allow for additional compaction under vehicular traffic and to accommodate slight expansion of the asphalt binder as the temperature increases in the summer months. The air voids in an asphalt mix is related to the durability of the mix.”

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