Most of italian road superstructures are of semi-rigid and flexible type. Despite their widespread use, hot mix asphalt construction specifications and quality control / quality assurance testing plans, when employed, are still based on an empirical approach. Bituminous mixes not complying with specification are rejected or accepted with a price reduction (penalty) that is not based on the real performance and therefore it does not allow a rigorous life cycle cost analysis. In this paper a new methodology for the evaluation of pavement pay factor evaluation is presented. The methodology is based on a performance related approach. The core of the methodology is represented by a mechanistic empirical pavement design procedure that is employed in order to estimate pavement performance both in the “as design” and in “as built” condition. The pavement design procedure allows to evaluate pavement fatigue life and maximum rut depth as a function of bituminous mix properties, pavement layout, on site prevailing traffic and climatic conditions. Because of variability of bituminous mix properties due to, on one hand, the acceptance ranges reported in hot mix asphalt specifications and, on the other hand, in-situ mix production and laying operating conditions, a constrained Monte Carlo simulation, by means of an Latin Hypercube Algorithm, has been carried out in order to evaluate pavement performance. Following this stage, a criterion based on a Life Cycle Cost Analysis (LCCA) concept has been employed in order to evaluate the Payment Adjustment Factor (PF) to be applied to the Contractor as a function of the pavement performance in the as-built scenario as compared with that pertaining the as-design scenario. Basing on a typical pavement specification framework adopted in Italy, a case study has been examined and a regression model has been developed on data generated in the Monte Carlo simulation, in order to derive a Pay Factor prediction expression as a function of the normal deviates of relevant asphalt concrete properties affecting pavement performance. Preliminary results seem to indicate that this approach may be useful both in the design stage, in order to take into account the pavement performance reliability, and in the construction stage, as a reference for the contractor to allow the production and the laying of high quality bituminous mixtures.
Nicolosi, V., D'Apuzzo, M., Mattarocci, M. (2005). A rational approach for the evaluation of pavement pay factor. In People, land environment and trasport infrastructures – releability and development. Bari.
A rational approach for the evaluation of pavement pay factor
NICOLOSI, VITTORIO;
2005-09-01
Abstract
Most of italian road superstructures are of semi-rigid and flexible type. Despite their widespread use, hot mix asphalt construction specifications and quality control / quality assurance testing plans, when employed, are still based on an empirical approach. Bituminous mixes not complying with specification are rejected or accepted with a price reduction (penalty) that is not based on the real performance and therefore it does not allow a rigorous life cycle cost analysis. In this paper a new methodology for the evaluation of pavement pay factor evaluation is presented. The methodology is based on a performance related approach. The core of the methodology is represented by a mechanistic empirical pavement design procedure that is employed in order to estimate pavement performance both in the “as design” and in “as built” condition. The pavement design procedure allows to evaluate pavement fatigue life and maximum rut depth as a function of bituminous mix properties, pavement layout, on site prevailing traffic and climatic conditions. Because of variability of bituminous mix properties due to, on one hand, the acceptance ranges reported in hot mix asphalt specifications and, on the other hand, in-situ mix production and laying operating conditions, a constrained Monte Carlo simulation, by means of an Latin Hypercube Algorithm, has been carried out in order to evaluate pavement performance. Following this stage, a criterion based on a Life Cycle Cost Analysis (LCCA) concept has been employed in order to evaluate the Payment Adjustment Factor (PF) to be applied to the Contractor as a function of the pavement performance in the as-built scenario as compared with that pertaining the as-design scenario. Basing on a typical pavement specification framework adopted in Italy, a case study has been examined and a regression model has been developed on data generated in the Monte Carlo simulation, in order to derive a Pay Factor prediction expression as a function of the normal deviates of relevant asphalt concrete properties affecting pavement performance. Preliminary results seem to indicate that this approach may be useful both in the design stage, in order to take into account the pavement performance reliability, and in the construction stage, as a reference for the contractor to allow the production and the laying of high quality bituminous mixtures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
