Book Description

This study was conducted to evaluate thickness requirements for membrane encapsulated soil layers (MESL) having various surfacing materials when subjected to 100 passes of F-4C aircraft loading and to determine the feasibility of constructing thin layers (5 to 9 inches) of MESL on low strength subgrade. A test section consisting of five items was constructed and trafficked. All five items were constructed on a prepared subgrade having a rated California Bearing Ratio (CBR) of 7. Thicknesses of MESL base courses were 9, 5, 7, 9, and 9 inches for items 1 through 5, respectively. Surfacing material consisted of 4 inches of asphaltic concrete on items 1 and 2, 2 inches of asphaltic concrete on item 3, only the waterproof surfacing of the MESL on item 4, a synthetic turf on item 4A, and a 1-1/2-inch-thick sod on item 5. The significant findings of this study are that (1) thin MESL base courses can be constructed over a 7 CBR subgrade; (2) a MESL with only the waterproof surface will structurally withstand 10 coverages of F-4C traffic but may be rendered susceptible to water due to wrinkling of the waterproof surfacing under traffic; (3) a MESL is susceptible to infiltration of water when overlaid with a layer of wet material such as sod; and (4) a MESL base course 7 inches thick with a 2-inch surfacing of asphalt concrete constructed on a 7 CBR subgrade will withstand 14 coverages (approximately 140 passes) of F-4C traffic. (Author).