TABLE 11.20 Recommended Drainage Coefficients for Untreated Bases and Subbases in Flexible Pavements Percentage of time pavement structure is exposed Quality of drainage to moisture levels approaching saturation Water removed Less than Greater than Rating within 1% 1-5% 5-25% 25% Excellent 2 hours 1.40-1.35 1.35-1.30 1.30-1.20 1.20 Good 1 day 1.35-1.25 1.25-1.15 1.15-1.00 1.00 Fair 1 week 1.25-1.15 1.15-1.05 1.00-0.80 0.80 Poor 1 month 1.15-1.05 1.05-0.80 0.80-0.60 0.60 Very poor Never drain 1.05-0.95 0.95-0.75 0.75-0.40 0.40 Source. Introduction to Pavement Design: Flexible Pavement Design Analysis Period (years) Chart for Estimating Structural Layer Coefficient of Dense-Graded Asphalt Concrete Based on the Elastic (Resilient). The following additional information is available: Mr of asphalt concrete = 400,000 1b/in2 Mr of base course material = 28,000 1b/in2 Mr of subbase course material = 13,000 lb/in2 Mr of subgrade = 1400 lb/in2 Reliability level (R) = 90% Standard deviation (So) -0.43 Initial and Terminal Serviceability Index are, pi = 4.5 and pt = 2.5 Use AASHTO empirical equation and graph and find SN, log[APSI/(4.2 - 1.5)) log W18 = ZpSo + 9.36 log(SN + 1) - 0.20 + 0.4 + 1094/(SN + 1)5.19 + 2.32 log MR - 8.07 Design Serviceability Low, apsi "S 10 90 40 போட்டபட்டாம்பட்டம் Estimated Total 1 kip FSAL Applications W millions) Overall Standar Effective Houdbed Soil Resilient Modulus, M, (ib/in">X10. It takes about a month for water to be drained from within the pavement and the pavement structure will be exposed to moisture levels approaching saturation for 50% of the time.
Transcribed image text: = Q1 Design using AASHTO Method A flexible pavement for a rural major highway carry a design ESAL of 1.2x106.