The RODECO Group has been commissioned by ROADGRIP Ltd to perform a series of high-performance surveys on 10 Cuban airports, managed by ECASA, in order to be able to determine the current state of the pavements, with a view to future expansion of the airports due to the increase of passengers on the island, and consequently of flights.
For the above airports, the following high-performance surveys were carried out:
Bearing capacity tests using HWD (Hevy Falling Weight Deflectometer), in order to determine the structural health of pavements, both rigid and flexible;
Longitudinal roughness surveys using a laser profilometer, in order to obtain the IRI (International Roughness Index) and BBI (Boeing Bump Index) indices, to determine the health status from the functional point of view of the pavements;
Friction tests using GripTester on the Runways, to detect the skid resistance of the pavement surface, in order to determine the necessity of rubber removal.
The survey campaign was carried out in the months of February-March 2019, a winter period which however recorded high temperatures for the pavements. Despite this, the surveys also took place during the daytime, especially in those airports where air traffic was less.
As previously reported, one of ECASA’s aims was to verify the current state of their infrastructures, requesting to also analyze military areas that have been abandoned for years, with the aim of reusing them to develop the airport areas making them suitable to accommodate the growth of the aicraft movements, even large ones. In fact, among the aircraft that mostly use these pavements there are Airbus class A330 and A340, and Boeing 747-767-777. It’s therefore possible to deduct that the pavements are subjected to heavy loads, with important traffic flows continuously increasing.
The surveys made by the undersigned are intended only as a first step, to be framed within a global pavement management system, aimed at determining which are the most suitable maintenance strategies both in economic terms and performance effectiveness. ECASA plans in the future to acquire these software, which can facilitate maintenance planning.
The bearing capacity tests have been carried out at network level on all the pavements of the detected airports, in order to know the whole condition of the infrastructures and highlight the areas having lack of bearing capacity, to plan rehabilitation or reconstruction maintenance in the next years.
The tests were therefore performed, as reported in the FAA AC regulation n.150 / 5370-11b “Use of Nondestructive Testing in the Evaluation of Airport Pavements” on the following alignments:
+ 3 m from the centerline;
– 3 m from the centerline.
The results of the HWD tests were reported in tabular, graphical and KML format, for easy viewing by the customer.
As can be seen, at each point, which is characterized by a geographical coordinate in the WGS84 coordinate system acquired at the time of the test, the results coming from the backanalysis were associated: by clicking on the point itself, the table of results opens. For the latter format, the results have also been reported in a histogram graphs, easy to visualize, in a color scale from red to green, in order to immediately determine which areas have bearing capacity problems.
Laser Profilometer surveys and friction tests have been carried out only on the Runways, because it’s the most important area of an airport.
The Laser profilometer survey, for the detection of the IRI and BBI (Boeing Bump Index) indices, have been carried out following the FAA AC n.150/5380-9 “Guidelines and Procedures for Measuring Airfield Pavement Roughness” on the alignements:
± 3 m to the centerline;
± 6 m to the centerline.
The results of the roughness tests were returned in tabular and graphical format, for easy viewing by the customer.
In the KML format, the results were reported in line graphics, easy to visualize, on a red – green scale, in order to immediately determine which areas present roughness problems.
The skid resistance surveys hase been conducted only on the Runways because they are the only areas where there is the aircraft rubber deposit, able to reduce the friction in the touch-down zone.
The tests were performed with the GripTester equipment, following the recommendations provided by ICAO Annex 14 regarding the execution of the tests on the following alignments (and at predefined speeds):
± 3 m at 65 Km/h;
± 6 m at 65 Km/h;
± 3 m at 95 Km/h;
± 6 m at 95 Km/h.
The results are ready at the end of the test, for immediate feedback of any critical issues on the flooring. Here is an example of the result obtained, for a detected alignment.
In the picture above the touch-down zone was highlighted in blue: it has presents evident deficiencies in terms of friction: one of the most encountered problems in Cuban airports was the accumulation of rubbery deposit that needed removal in order to restore friction lacking.
The RODECO Group, in addition to checking the current state of the pavements, also suggested various types of maintenance interventions to be applied in the medium/short term in order to restore those critical issues highlighted at the end of the surveys.
Many pavements had reduced thickness of the asphalt layer, applied on rock bed or extremely rigid subgrade. In these extreme conditions, only the asphalt layer that is affected by the stresses due to the applied loads, because they cannot propagate in depth due to the stiffness of the subgrade. Partial rehabilitation interventions have therefore been suggested, through the application of special glass fiber geogrids, able of absorbing the tensile stresses at the bottom of the asphalt. These treatments are also aimed at restoring the longitudinal roughness deficiencies highlighted in many of the detected airports.
Other suggested applications were mainly preventive maintenance, among which:
– Waterblasting removal of rubber deposit on the touch-down zone, able to don’t damage the pavement surface restoring friction and macrotexture;
– Crack sealing on asphalt pavements, in areas with good results of bearing capacity and roughness, but having some problems about surface distress
– On the rigid pavement: joint&crack sealing, partial-depth patching, in the areas where there are corner break and spalling joints.