Consideration of Preservation in Pavement Design and Analysis Procedures (2015) / Chapter Skim
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Pages 36-54
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36 C H A P T E R 6 The application of preservation treatments could result in changes in pavement material properties (e.g., modulus) , pavement structural properties (e.g., thickness, moisture content)
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37 of HMA or diamond grinding of PCC, or increased, as in the case of applying a surface treatment or thin HMA overlay. Although some treatments with large thicknesses are applied and treatments that are placed repeatedly over time could increase structural capacity, pavement preservation treatments are generally considered to have no effect on structural capacity.
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38 Treatment Performance Indicator Total Rutting (HMA and unbound) Transverse Thermal Cracking Fatigue Cracking (Bottom-up Alligator)
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39 Input Level 1 Level 2 Level 3 Unit Weight AASHTO T 166 Not applicable Typical value (default = 150 lb/ft3) Effective Binder Content AASHTO T 308 Not applicable Typical value (default = 11.6%)
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40 The empirical reflection cracking model can be used to predict the percentage of cracks (fatigue and thermal) or joints that propagate through the preservation treatment over time.
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41 materials properties, a specific design life, reliability levels for the individual performance indicators, and performance indicator threshold values for rehabilitation. Either the MEPDG performance prediction models or locally calibrated models can be used.
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42 to the default values provided in the Pavement ME Design software. Example 1: HMA Pavement Preservation Step 1: Identify Baseline Pavement Design and Preservation Treatments The specifics of the baseline pavement design are: • Pavement type: Conventional flexible pavement • Design period: 20 years • Functional class: Principal arterial • Traffic: – Truck traffic classification (TTC)
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43 77 Unit weight: 150 lb/ft3 (default) 77 Effective binder content: 10% 77 Air voids: 4% 77 Poisson's ratio: 0.35 (default)
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44 Step 6: Identify Immediate Effect of Treatment Application on Existing Condition It is assumed that the application of the microsurfacing will reduce the rut depth to zero and IRI to 90 in./mi. Step 7: Determine Dynamic Model The dynamic model will assume reductions of the rut depth to zero (see Figure 14)
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46 Pr ed ic te d Di st re ss o r I RI Age Baseline Design PreservationTreated Design Extend Pavement Life Threshold for service life Figure 20. Illustration of the effect of preservation treatment application on pavement life.
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47 Distress Distress Criteria At 10 Years (prior to overlay/microsurfacing) At 20 Years (10 years after overlay/microsurfacing)
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48 0 50 100 150 200 0 5 10 15 20 IR I ( in ./m i) Pavement Age (years)
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49 0 20 40 60 80 100 0 5 10 15 20 To ta l C ra ck in g (% ) Pavement Age (years)
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50 – Thermal properties 77 Coefficient of thermal expansion: 5.5 in./in./°F × 10–6 (default) 77 Thermal conductivity: 1.25 BTU/hr-ft-°F (default)
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51 0 50 100 150 200 0 5 10 15 20 25 30 IR I (i n./ m i) Pavement Age (years)
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52 0 5 10 15 20 0 5 10 15 20 25 30 Tr an sv er se C ra ck in g (% sl ab s) Pavement Age (years)
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53 Distress Distress Criteria At 20 Years (prior to grinding) At 30 Years (10 years after grinding)
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54 0 5 10 15 20 0 5 10 15 20 25 30 Tr an sv er se C ra ck in g (% sl ab s) Pavement Age (years)
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