Intermodal Way Extension

With an assumed subgrade R-value of 50, the initial pavement section design of 7 inches of asphalt concrete (AC) and 8.5” inches of aggregate base (AB) were sufficient to meet the required Traffic Index (TI) of 11 for this critical commercial roadway. However, prior to construction, the engineer performed verification R-value tests. The test results showed that the subgrade soils had R-values less than 50. The new pavement section design with the lower R-Value would require an additional 7 inches of AB to meet the required TI. The new pavement section was not constructable due to shallow utilities within the roadway.

Tensar proposed a solution using InterAx NX750 geogrid. Adding NX750 geogrid at the interface between the subgrade and AB creates a stiff, mechanically stabilized base layer that reduces stresses on the subgrade. This allowed the project team to construct the pavement section as originally planned, eliminating the need for the the additional 7 inches of aggregate.