Improved Drainage and Frost Action Criteria for New Jersey Pavement Design. Phase 2. Frost Action.

摘要

With the assistance of the Federal Highway Administration, the New Jersey Department of Transportation (NJDOT) is studying the feasibility of including open-graded drainage layers in their highway pavements. Before constructing actual pavements with open-graded drainage layers they chose to analytically examine the influence of the drainage layer on frost penetration beneath hypothetical pavements, CRREL conducted the analytical study under a contract with the NJDOT. Thermal conductivity values of several New Jersey soils, stabilized drainage layer materials, and pavement samples were measured using the Guarded Hot Plate method or the probe method. Measured values for the soils were somewhat less than predicted from Kersten's equations and ranged from 0.77 to 1.90 Btu/ft hr F. Measured thermal conductivity values for the pavement samples were also somewhat lower than Kersten's observations. Frost penetration depths were computed using the modified Berggren equations. Mean air freezing indexes used in the computation ranged from 50 F - days in Atlantic City to 480 F - days in Newton. Design freezing indexes ranged from 250 F - days to 900 F - days for the same two sites. Maximum computed frost depths ranged from 0.8 to 2.1 ft beneath conventional pavements, i.e. those without drainage layers.