Asphalt mixing is much more than just throwing rocks and glue in a mixing tank.
HMA or Hot Mix Asphalt, consists of an aggregate, like stone, and an asphalt binder, aka the glue that holds it all together.
There are 3 common testing methods that are used.
Hveem, Marshall and Superpave Methods
All 3 of these methods are basically the same. They consist of 3 basic steps.
1, Aggregate selection. 2, Asphalt binder Selection. 3, Testing.
Testing is what really sets them apart.
Hveem method is the most “advanced” method by far.
By advanced, we mean it takes slightly more advanced machinery to test. So generally more expensive to test with.
The Marshall method is most commonly used throughout the industry due to its relatively light, portable and inexpensive testing equipment.
Originally developed by Bruce Marshall in 1939 and then improved upon by the U.S Army.
The Marshall method is popular due to its simplicity, lower cost equipment and good track record.
The Superpave method is the newer kid on the block.
Being newer, there is still a lot of research going on with the overall performance testing of this method.
But that doesn’t mean this method is not proven and tested.
This method doesn’t require too advanced testing machines, it’s relatively cheap to test with.
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