Assessment:

The project location (Gary, IN) is adjacent to Lake Michigan, and heavy spring rains and rising lake levels resulted in an abnormally high water table, which extended into the pavement base in areas. The high water table and the proposed pavement elevation limited available types of subgrade improvement made the undercut depth specified by the original design unfeasible.

Solution:

Two layers of Tensar TriAx geogrid reduced the undercut depth and minimized disturbance with the high water table. To provide additional separation and reinforcement, Mirafi RS580i geotextile was placed first.  TX190L geogrid was placed on top of the RS580i with 6” of No. 2 stone to create a working platform. The No. 2 stone was static rolled to avoid any over pumping of the subgrade. Then the second layer of grid, TX160, was placed directly on top of the No. 2 stone and 7” of No. 53 stone was placed on top of the TX160. This was then compacted with a low-vibratory roller.

Summary:

This integrated design utilizing multiple products to maximize effectiveness passed proof-roll and the 12.5” asphalt section was then paved per plan.

Products Used:

Tensar TriAx geogrid

TenCate Mirafi Rs580i geotextile