Development of Drainage Coefficients and Loss of Support Values for Pavement211 Design in Nebraska

摘要

A chart of drainage time to achieve 50 percent saturation for bases and subbases211u001ewith edge drains was developed. Using this cart recommended values for drainage 211u001ecoefficients for portland cement concrete (PCC) and asphalt cement (AC) pavements 211u001ecan be determined from the 1993 American Association of State highway and 211u001eTransportation officials (AASHTO) Design Guide. At the sites evaluated, pavement 211u001edrainage in Nebraska is rated Poor to Very Poor. Therefore C(d) will range from 211u001e0.95 to 0.70 depending on topography of the right-of-way and climate. LS values 211u001eof 1 to 1.5 are appropriate for design, unless highly permeable non-erodable 211u001esubbases are designed so that pavement drainage can be rated Good. A computer 211u001emodel which incorporates the AASHTO 1993 Design equation of PCC concrete pavement 211u001eis presented in a spreadsheet for mat that provides ease of design for evaluation 211u001eof alternate criteria and material properties is presented. Two design examples 211u001erepresenting conditions at one of the test sites are presented. The examples 211u001eassume poor and good drainage for design assumptions comparison.