Performance-Related Specifications for Pavement Preservation Treatments (2017) / Chapter Skim
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104 Joint Resealing The steps presented in Chapter 5 were followed to develop an example for joint seal/reseal treatment in rigid pavements.
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Appendix A 105 % 100 (A-1) L L L fail f total = × where %Lfail = percent length of a joint allowing water to enter Lf = total length of a joint allowing entrance of water Ltotal = total joint length evaluated These percentages can be determined through a visual examination or using devices such as the Iowa vacuum (IA-VAC)
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106 performance-Related Specifications for pavement preservation Treatments Figure A-3. Joint faulting over time for PCC pavement sections.
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Appendix A 107 The change in performance was quantified using the SLE, which is the difference in the time between before and after treatment to an established threshold for faulting. The SLE can be determined by using Equation A-3.
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108 performance-Related Specifications for pavement preservation Treatments Equation A-4 shows that a positive or negative value of D%Leff-total correlates with a positive or negative effect of joint resealing, i.e. a positive parameter (increase in percent of joints effectively resealed)
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Appendix A 109 Summary • The AQC selected for the development of the joint reseal PRS guidelines is percent of joints effectively sealed within a section (D%Leff-total)
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110 performance-Related Specifications for pavement preservation Treatments The DPWL shows how much the construction quality has statistically demonstrated a shift toward or away from acceptable quality. A positive DPWL value indicates an improvement in AQC due to resealing; a negative value indicates a decline in quality.
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Appendix A 111 2. Convert the expected performance into pay adjustment.
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112 performance-Related Specifications for pavement preservation Treatments This decision is typically made to meet the needs of the agency to ensure that the pavement performs up to established standards. For instance, in the EP curve values shown in Table A-2, an agency may decide that a life extension of less than 3 years is undesirable.
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Appendix A 113 the pay adjustment plan that will award a pay factor greater than 1 has a probability of 50% of all lots sampled. This suggests that the contractor will receive pay greater than 100% (pay for above AQL)
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114 performance-Related Specifications for pavement preservation Treatments 2. Select Candidate Material and Construction Characteristics and Performance Measures The candidate material and construction variables that can be used when performing DBRs include • Mortar properties (flow, compressive and flexural strength, shrinkage, bond strength, absorption)
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Appendix A 115 C C C (A-11b)
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116 performance-Related Specifications for pavement preservation Treatments was established as 95%, given that an LTE of 100% is difficult to achieve. Typically, a LTE of 90 to 95% can be achieved through a successful DBR.
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Appendix A 117 shows the predicted faulting over time for the pavement section. Given that the predicted value for faulting reasonably correlates with the measured value at about 7 years, the DE and LTE models shown in Figure A-9 were used to develop a relationship between LTE and DE (see Figure A-11)
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118 performance-Related Specifications for pavement preservation Treatments Figure A-14 shows the relationship established between DLTE and SLE for Section 32-A410. The relationship shows that a larger change in DLTE results in a higher SLE.
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Appendix A 119 3. Decide on the quality measure.
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120 performance-Related Specifications for pavement preservation Treatments field manual for measuring FWD deflections specifies several sampling plans which correspond to experiment and pavement type. For rigid pavements, the guidelines specify a maximum of 100 deflection tests performed within a 500-ft pavement section (FHWA 2000)
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Appendix A 121 2. Convert the expected performance into pay adjustment.
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122 performance-Related Specifications for pavement preservation Treatments Equation A-18 can be used for risk assessment to develop EP curves, assess the associated a and b risk, and determine the appropriate AQL and RQL levels necessary to award payment factors.
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Appendix A 123 When evaluating the risks associated with receiving appropriate pay for the predicted change in the PWL, the OC curves can be examined. Figure A-17 shows the OC curves of desired quality DPWL = 44 (i.e.
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124 performance-Related Specifications for pavement preservation Treatments Thin Overlay The PRS guidelines presented in Chapter 5 were used to develop an example for thin overlay treatment in flexible pavements. The following AQCs and performance measures were identified and selected: 1.
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Appendix A 125 between existing surface roughness and predicted performance measures of asphalt pavements. The IRI and DLI are expected to decrease in magnitude as roughness decreases.
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126 performance-Related Specifications for pavement preservation Treatments (a)
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Appendix A 127 • The results of the dynamic load analysis for the pavement sections showed that treatments which could reduce the surface roughness generally reduced the dynamic loads. This suggests that there is a positive correlation with an effective thin overlay treatment which reduces roughness and the resulting dynamic loads experienced by the pavement.
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128 performance-Related Specifications for pavement preservation Treatments • A shift in the dynamic loads after thin overlay treatment should be reflected in the resulting predicted performance (cracking, rutting, and IRI)
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Appendix A 129 • The relationships established between DIRI (IRI after overlay - IRI before overlay, similarly with DLI) and predicted performance at the end of 20 years (in terms of IRI)
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130 performance-Related Specifications for pavement preservation Treatments smoothness. Therefore, a one-sided upper specification limit of 90 inch/mile was adopted and used for evaluating quality measures, pay adjustments, and risks.
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Appendix A 131 profilers are limited in that most are set up to only measure a single wheel path and require at least two carefully coordinated runs to obtain complete profile data for one lane. The FHWA Highway Performance Monitoring System (HPMS)
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132 performance-Related Specifications for pavement preservation Treatments 7. Select and Evaluate Quality Measurement Methods As discussed in Chapter 5, the quality measure will be DPWL.
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Appendix A 133 relationships developed. Subsequently, these results were used to develop a relationship between SLE due to thin overlay and DPWL.
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134 performance-Related Specifications for pavement preservation Treatments ( )
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Appendix A 135 level below that will receive no pay. Simultaneously, the agency is also deciding that any quality between AQL of 20.5 DPWL and RQL of 5 DPWL will be accepted, but will receive reduced pay or a disincentive.
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136 performance-Related Specifications for pavement preservation Treatments award pay factor greater than 1 has a probability of 50% that the contractor will receive pay greater than 100% (pay for above AQL) half the time and receive pay less than 100% (pay for below AQL)
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Appendix A 137 is applied on an existing pavement surface primarily to seal low-severity cracks and rutting and to mitigate raveling and asphalt oxidation (Peshkin et al.
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138 performance-Related Specifications for pavement preservation Treatments Equation 6-2 was used to estimate the friction number (FN) for given MPD values in Table A-14.
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Appendix A 139 To translate the above AQC for measuring construction quality for a preservation treatment, a change in the AQC before and after microsurfacing must be measured. Therefore, measuring the magnitude of MPD before and after treatment can quantify the effectiveness of microsurfacing.
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140 performance-Related Specifications for pavement preservation Treatments relationship is established only as an example for illustration and not as a standard specification. An agency can adopt this procedure using measured DMPD data to establish such relationships to develop PRS guidelines for microsurfacing.
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Appendix A 141 5. Specify Test Methods to Measure AQC Established standards, such as ASTM E2157, can be used for measuring and evaluating surface texture.
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142 performance-Related Specifications for pavement preservation Treatments 8. Develop Pay Adjustment Factors for Incentives and Disincentives The relevant expected pay (EP)
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Appendix A 143 where PF = pay adjustment factor for treatment (same units as C) C = present total cost of treatment, use C = 1 for PF D = design life of pavement or initial overlay E = expected life of pavement or overlay O = expected life of successive overlays R = (1 + INF)
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144 performance-Related Specifications for pavement preservation Treatments payment that correctly corresponds to the level of quality sampled. Figure A-33 shows these OC curves.
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Appendix A 145 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 020406080100 Pr ob ab ili ty o f r ec ei vi ng a p ay fa ct or 1 n=3 5 10 20 30 30.3 AQL = PWL of 30.3 PWL Figure A-33. Predicted OC curves for microsurfacing.
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146 performance-Related Specifications for pavement preservation Treatments Henry, J
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Abbreviations and acronyms used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FAST Fixing America's Surface Transportation Act (2015) FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012)
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TRA N SPO RTATIO N RESEA RCH BO A RD 500 Fifth Street, N W W ashington, D C 20001 A D D RESS SERV ICE REQ U ESTED ISBN 978-0-309-44661-7 9 7 8 0 3 0 9 4 4 6 6 1 7 9 0 0 0 0 N O N -PR O FIT O R G .
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