NDT application in Transport Asset Management. QA/QC performance specifications in pavement construction and maintenance

Abstract

Nowadays, in Transport Asset Management, there is the need to identify measures to guarantee high levels of performance over time. The application of Non-Destructive Techniques, through high-efficiency equipment, turns out to be an optimal solution to ensure the quality of transport infrastructures. Asset Management take into account the importance of monitoring the performance characteristics of the transport infrastructures and QA/QC performance-based contracts specifications in order to guarantee the preservation of environmental, social and economic resources, as well. This study consists of two parts of research activity: in field tests and numerical simulations. The first part consists of in situ experimental activities to investigate both road and rail transport infrastructures. The tests have shown the versatility of high-performance instruments, such as FWD, LWD, GPR and ARAN, in railway monitoring, in the evaluation of ballast conditions and sleeper/ballast interaction, and also in the reuse of volcanic ashes that after stabilization can be used in road subbase layers. The high-efficiency equipment allow a faster execution of the tests with the possibility of a higher number of measurements, the combination of several instruments at the same time with a continuous mapping of the infrastructures, performance measures and a significant cost reduction. In the second part, the study focuses more specifically on road pavements. Considering several flexible pavements pulled out from the Italian Catalog, numerical simulations of FWD tests were carried out in the hypothesis of multilayer elastic theory with the aim to develop performance-based criteria and specifications for QC of pavement construction work. The results allow to estimate effects of structural deficits in the perspective of future performance and Life Cycle Cost Analysis in order to quantify penalties to restore expected higher maintenance costs.