This paper presents ongoing research to measure the in situ response to airplane traffic of flexible pavement on a runway at Cagliari-Elmas Airport in Italy. Understanding how pavement materials respond to traffic and environmental loading is fundamental to designing pavements and assessing their performance. The pavement material behavior is affected by many factors (i.e., load magnitude, material properties, and environmental conditions). The influence of these factors can be simultaneously taken into account by measuring in situ stresses and strains using embedded instruments. The pavement layers of the Cagliari-Elmas runway were equipped with 149 instruments: 36 linear variable differential transformers, 36 pressure cells, four time domain reflectometers, 28 T-thermocouples, and 45 hot-mix asphalt strain gauges. The instrumented area, 55 m2, allows measuring the responses during three main loading maneuvers: taking off, landing, and taxiing. The preliminary data acquired during and after the runway's construction and before its opening to airplane traffic and its analysis show that the instrumentation process was a success. The instrument response testing includes falling weight deflectometer, truck, and airplane loading of various types, magnitudes, and speeds. The collected data were successfully compared with preliminary numerical simulations. Further data collection and research will be performed, particularly involving airplane traffic data. Data analysis will include the effect of the environmental data (i.e., moisture and temperature) and airplane configuration and speed. The collected data will be used to validate advanced pavement modeling and predict pavement runway performance. In addition, data resulting from this research have the potential to support and improve runway pavement design and to improve the evaluation process for new and existing runway pavement performance and damage prediction.

The objective of this paper is to analyze runway pavement responses under moving\ud aircraft tire loading using a developed three-dimensional (3-D) finite element (FE) model.\ud The instrumented runway at Cagliari-Elmas airport (Sardegna, Italy) was modeled in the\ud analysis, which consists of a 350-mm asphalt layer, a 400-mm granular base layer, and\ud subgrade. The FE model characterized the asphalt layer as a linear viscoelastic material,\ud and two interface bonding conditions between asphalt layers (full bonding and partial\ud debonding) were used in the analysis. The aircraft tire loading was simulated using a\ud nontraditional loading assumption that represents the non-uniform distribution of tire\ud contact stresses along contact length and width under five ribs of an aircraft tire. Analysis\ud results show that traditional loading assumption that assumes uniform contact stresses at\ud the tire-pavement interface underestimates the critical tensile and shear strains in the\ud asphalt layer. In particular, the relatively high contact stresses at tire edge ribs under\ud heavy aircraft loading cause significant shear stresses at the pavement near-surface. The\ud pavement responses under various loading conditions (aircraft type, wheel load, and\ud speed) were calculated, and the critical responses were identified. Good agreements were\ud achieved when the calculated pavement responses (vertical pressure and horizontal strain)\ud at various locations were compared to the measured responses from field instrumentation.\ud The model results show that partial debonding between asphalt layers causes much\ud greater tensile strains at the bottom of the whole asphalt layer

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The load-carrying capacity, is one of the indicators used to assess airfield pavement conditions. It could be estimated by evaluating the response of stationary dynamic loads, using a deflectometric device that simulates the stress inducted by an aircraft moving at moderate speed. This device is widely used because tests are nondestructive and rapid to execute and can be conducted for cyclic investigations, providing valuable support to maintenance and rehabilitation (M&R) decision makers through pavement management system (PMS). Pavement response is evaluated as a function of the deflection basin induced by the deflectometric device. It is well known that deflectometric measurements are influenced by external parameters such as weather conditions, especially temperature of upper layers or the percentage of water contained on unbounded layers. In this study the deflections basin response obtained for different load and weather conditions has been analyzed through the application of benchmarking values for immediately structural assessments. Tests were performed using the Heavy Weight Deflectometer (HWD) on 9 points along five longitudinal alignments from the centerline, 0.00 m, ± 3.00 m, and ± 5.20 m. The benchmarking methodology was used to evaluate and compare runway pavement performance under different weather conditions and testing loads. The applied benchmarking methodology resulted an easy and rapid assessment tool of pavement conditions at network-level.

The conditions of airport movement-area pavements play a primary role on safety and regularity of airport operations; for this reason, the aerodrome operator needs to periodically survey their condition and provide their maintenance and rehabilitation in order to ensure the required operational characteristics. To meet these needs efficiently and effectively, the Airport Pavement-Management System (APMS) has proved to be a strategic tool to support decisions, aimed at defining a technically and economically sustainable management plan. This paper aims to investigate the theoretical elements and structure of the APMS; the appropriate methodologies to guarantee a constant updating of the system in all its aspects are presented, focusing on the specific case study of a medium-dimension Italian airport. The article describes the methods and the equipment used for the high-performance surveys and the condition indexes used for collecting and analyzing the data implemented to populate the APMS of Cagliari airport. Two major survey campaigns were carried out: the first in 2016 and the second in 2019. Both surveys were carried out using the same subdivision into sample units, following the ASTM D5340-12 criteria, to correctly compare data collected in different years. In order to sufficiently populate the APMS database, the measured and back-calculated data were stored and integrated using daily acquired pavement reports since 2009 and stored with the specific intention to develop customized decay curves for Cagliari Airport pavements. Preliminary results on the sustainable use of the APMS were reported even with data collected in a limited period and successfully applied to runway flexible pavement.