The Benkelman beam touches down on the prepared subgrade, its dial gauge steadying as the truck applies the standard axle load. In Newark, where the underlying geology shifts from glacial lake sediments of the Hackensack Meadowlands to the weathered shale of the Piedmont, these deflection readings tell the real story of subgrade support. We correlate the elastic rebound with the laboratory-determined resilient modulus, feeding the layered elastic analysis that defines the asphalt concrete thickness and base course gradation. The city’s 40.7° N latitude means the pavement section must also resist frost penetration depths that regularly exceed 30 inches. A CBR road test provides the soaked strength index we use to validate the structural number before approving the final pavement profile.
A correctly engineered flexible pavement distributes tire contact pressure through the HMA, base, and subbase layers so that the vertical stress at the subgrade interface never exceeds the soil’s bearing capacity.
