Example N01.2: Use RHMA-G surface

In this subsection, the alternative of introducing RHMA-G is examined. Specifically, an RHMA-G layer of between 0.20 and 0.50 ft is placed as the surface. The total asphalt concrete (AC) thickness required is expected to either be the same or reduced.

To evaluate this alternative, save the original trial under a new name "Example N01.2 Use RHMA-G Surface". Use the "Insert" link for layer 1 to add a layer on top of the HMA and pick "RHMA-G" from the "Layer Type" drop down list. There is only one RHMA-G mix available at this time.

The "Project Information" page for 0.50 ft RHMA-G + 0.50 ft HMA is shown below.

And the corresponding simulation results are shown below:

After running some Monte Carlo simulations, the required thickness combinations are determined and shown below in Table 1. As shown in the table, using 0.20 to 0.50 ft of RHMA-G reduces the combined thickness for asphalt bound layer by 0.05 ft. In other words, the HMA can be replaced with RHMA-G at roughly 1:1 ratio up to 0.50 ft.

Table 1: Required thickness combinations for the AC layers