The construction of caisson breakwaters dates from ancient times (Brindisi battle and Caesarea Maritima, Roman Empire) of yore but has evolved with regards to technology and the materials available at all times (wood, gravel, and rubble mound). The growth in draught in vessels searching for deep water depths for berthing plus environmental problems have led to the 20th century facilitating the boom in vertical types and concrete caissons built in different ways (dry and floating techniques). Furthermore, structural criteria gave way to functional, environmental, and aesthetic criteria. The search for new, more efficient forms led to the construction of increasingly more complex elements including many that still require an economically viable construction system. To where will this search for new materials and forms take us? The use of composite materials could be considered, at the moment, as too expensive, but analyzing the cost with a wider approach, as Life Cycle Assessment, shows us that caissons in composite materials are cost effective and could be a solution. Furthermore, the possibility of using recyclable composites opens up big opportunities of using these materials at affordable costs. Caissons in composites or recycled composites are then a real alternative to concrete caissons. In Spain, two examples can be observed: a berthing area in Canary Island (Puerto del Rosario, South Atlantic Ocean) and a crown wall in Cartagena using polyester fiber bars (Mediterranean Sea). European policy in matters of sustainability promotes the circular economy, which means not only consider construction of caissons in recycled composites should be considered but also the comparison of all materials and construction procedures. Lastly, the calculation of the Environmental Product Declaration (EPD) should be promoted.

The 2030 Agenda and the Sustainable Development Goals are a necessity. A large number of public actions and activities in many countries go in this direction. Various indicators are used to quantitatively assess the impacts, all of which are included within product life cycle assessment. It is essential to study and assess infrastructure, as it is an important factor in emissions, as well as environmental and sustainable construction. In maritime works, the aggressiveness of seawater is an important factor that reduces the life of reinforced concrete structures, and it is necessary to search for solutions that reduce or eliminate maintenance. In this research paper, the aim is to quantitatively verify that the composite materials are viable from an environmental and resistant point of view. Concrete caissons and/or breakwater crowns for vertical breakwaters were constructed as the fundamental elements, calculating the life cycle in comparison with several contrasting examples. The first is the case of a conventional breakwater crown, built in Escombreras, southeast Spain, at the Mediterranean Sea, later simulating the impact with one reinforced with fiberglass bars. The results are encouraging and call for additional measures to further reduce maritime infrastructure indicators with much less polluting, more durable, and more sustainable solutions.

Abstract:The breakwater construction technique using floating concrete caissons is well-known nowadays as a widespread system. Yet do we really know its origin? Since Julius Caesar used this technology in Brindisi (Italy) up to the Normandy landings in June 1944, not only has this technology been developed, but it has been a key item in several moments in history. Its development has almost always been driven by military requirements. The greatest changes have not been conceptual but point occurring, backed by the materials used. Parallelisms can be clearly seen in each new stage: timber, opus caementitium (Roman concrete), iron and concrete . . . However, nowadays, achieving a more sustainable world constitutes a major challenge, to which the construction of caissons breakwaters must contribute as a field of application of new eco-friendly materials. This research work provides a general overview from the origins of caissons until our time. It will make better known the changes that took place in the system and their adaptation to new materials, and will help in clarifying the future in developing technology towards composite sustainable materials and special concrete. If we understand the past, it will be easier to define the future.