Logistic Simulations to Assess the Effect of Florida Department of Transportation’s Incentive and Disincentive Specifications on Long-Term Asphalt Pavement Performance

Abstract

The Florida Department of Transportation’s (FDOT’s) percent within limits (PWL) specification for acceptance and payment of asphalt materials was first implemented in 2002. The objective of this study was to determine the effect that FDOT’s PWL specification has on the long-term performance of asphalt pavements. In this study, multinomial logistic regression analysis (MLRA) was used to assess the effect of FDOT’s PWL specification on long-term asphalt pavements. The MLRA results were used to determine the probability of a pavement section showing a higher level of long-term distress as a function of the composite pay factor (CPF). This probability indicates that FDOT’s CPF is cost-effective (i.e., the higher the CPF, the lower the probability of distress). Moreover, it was shown that CPF has a profound effect on cracking and raveling of both dense and open graded mixtures. The results of additional logistic simulation for dense graded mixtures indicate that FDOT’s new CPF weightings, implemented in the 2019 specification, may result in improved mixture quality and significantly reduce the probability of long-term cracking and raveling, compared with the original weightings in the 2002 specification. For open graded mixtures, although FDOT’s CPF original weightings, implemented in 2002 (and still being used), are cost-effective, the results indicate that the probabilities of cracking and raveling may be reduced further by updating the weightings for percentage passing a 3/8-in. sieve and percentage passing a No. 8 sieve.