The number of port, airport and coastal structures that have been used for a long time is increasing, and yet financial resources and the number of technicians for facility maintenance and management are limited. Important port, airport, and coastal infrastructure functions should be maintained, and so the strategic maintenance, renewal, and other approaches for such functions are strongly required.

Therefore, we will establish design methods for port structures and materials which are excellent in terms of maintenance, and will develop techniques regarding various countermeasures in the maintenance phase.

Regarding various construction materials in marine environments, we will conduct research on the following: evaluation of long-term durability, understanding of deterioration mechanisms, and investigation of the prevention effects of protective methods for steel structures. Especially, assuming that infrastructure is used overseas and on remote islands in Japan, we will improve material characteristics and durability under severe environments and under conditions in which low-quality material is used, and will investigate environmental-burden reduction, durability improvement, and environmental coexistence. In addition, regarding airport runways, we will improve methods to detect the separation of asphalt from aggregates, countermeasures against such separation, and the load-bearing characteristics of airport pavement. We will also investigate rapid repair techniques.

We will research and develop the following: inspection and diagnosing techniques using nondestructive inspection methods and sensors, unmanned investigation devices including ROVs, Non-contact ultrasonic thickness gauging system, and others. Especially, we will suggest a health-monitoring system which uses nondestructive inspection methods and monitoring methods for each type of structure. In addition, for open-type wharves, we will establish a system for selecting inspection and diagnosing methods according to the performance of structures to be evaluated and the accuracy of expected output.

We will conduct accelerated-deterioration tests of members of port structures, investigate performance-deterioration models which cover the entire lifecycle of structures, and validate such models through exposure tests in actual environments and through on-site investigation. We will also take into account the required properties and utilization of individual structures, budgets, and various limitations, and then suggest strategies of maintenance and management of district-based groups of port structures. 

We will use facilities with long-term exposure to predict chloride-induced concrete deterioration, and collect data on the durability of various wood materials.

Regarding the anticorrosion effects of cathodic protection methods on steel materials in actual environments, we compiled the results for many test pieces.

With the target of establishing methods for predicting the deterioration of protective coating methods, we analyzed samples from port structures which have actually been used for a long time. We also conducted accelerated-deterioration trials to determine the deterioration mechanisms of petrolatum coating construction methods.

We evaluated the durability of concrete which had been made with low-quality aggregates (coral) and seawater as mixing water and also started exposure trials to develop concrete curing techniques with seawater. In addition, we studied exposed specimens to evaluate the durability of highly-resistant reinforcing steel (including stainless reinforcing steel).

We answered inquiries from many regional developmental bureaus and bureau managers regarding maintenance techniques.

We conducted trials to evaluate the separation tolerability at the design phase of newly-paved asphalt pavement, organized separation-prevention methods, and then compiled the results.

We studied and organized the following: the required performance of aggregate gradation and warm mix asphalt when used in airport-asphalt pavement, and methods for testing and evaluating their performance. Then, we conducted pilot studies.

We collected cases of structural types and details to reduce maintenance work and then extracted and organized points to be considered for maintenance at both design and construction stages.

We investigated the following: multicopter drone utilization; development of sensors to confirm anticorrosion effects; inspection and diagnosing systems for port structures; corrosion monitoring to investigate the appropriate arrangement of sensors for RC materials; applicability of spatial statistics for streamlining maintenance; corrosion diagnostic technique for tie rods; development of corrosion sensors for steel material embedded in concrete; and others.

We refined an ROV for inspecting pier superstructures and noncontact thickness measuring equipment, conducted onsite trials, and identified the challenges and other matters.

We organized the following: reconstruction of performance degradation chains at mooring facilities; methods for evaluating the soundness of apron pavement with cavities; evaluation and prediction of durability of concrete structures; challenges to studying life extension and improvement of existing facilities; maintenance scenarios and LCC of pier superstructures; flow of selecting pier countermeasure methods; methods of correcting maintenance plans for port facilities; and other matters.