‘Sustainability’, ‘circular economy’, ‘circular construction’ have received increasing attention in the last decade. However, their interpretation is often unclear, as is the way a certain study fits into these research fields. In this paper, therefore, first a definition of both ‘sustainability’ and ‘circular economy’ is proposed. It is concluded that sustainability is the goal, while the circular economy is a means to achieve a more sustainable economy. Subsequently, the application of the circular economy in the construction industry is investigated, with a special focus on bridge construction. Reason is that, for instance, many concrete pedestrian bridges currently find themselves in the end-of-life phase, are demolished and often merely rebuilt, with a lot of material and energy loss as a consequence. An investigation of the available circular construction principles is therefore performed in order to determine certain limitations and gaps for future research and to stipulate the path to be followed towards circular bridge construction. This is necessary in order to prevent the same cycle of demolition and replacement from being run through again in a few decades. It is concluded that the meso-scale, the construction in general, is rarely discussed. Yet, an in-depth investigation is necessary in order to develop specific design strategies for circular bridges. A certain standardisation scheme to facilitate circularity, needs to be developed. This scheme should, however, still allow enough architectural freedom. Additionally, this scheme needs to be accompanied by, to be developed, meso-scale circularity indicators to effectively assess the eventual circularity of a bridge.

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Translating the circular economy to bridge construction: Lessons learnt from a critical literature review

Greener, cheaper, or more sustainable: Reviewing sustainability assessments of maintenance strategies of concrete structures

Sustainable design of infrastructures has become a major matter of study since the recent establishment of the Agenda 2030. This paper provides a systematic literature review on the use of multi-criteria decision making techniques used so far for the sustainable design of bridges. Special attention is put as well on how the reviewed studies assess the sustainable performance of bridge designs along their life cycle from the economic, the environmental and the social perspective. Although SAW and AHP are recurrently used in the sustainable assessment of bridges, the analysis of the most recent articles show that the application of TOPSIS and PROMETHEE techniques are gaining increasing relevance for such purpose. Most of the studies focus on the research of the construction and the maintenance stage of bridges. However, a need for further analysis is identified when it comes to the assessment of the impacts resulting from the End of Life cycle stage of bridges from a sustainable point of view. The use of intuitionistic and neutrosophic logic have been detected as emerging alternatives to the fuzzy approach of decision making problems.

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Life cycle sustainability assessment for multi-criteria decision making in bridge design: a review

On the fracture behaviour of fibre-reinforced gypsum using micro and macro polymer fibres

Fibre-reinforced concrete (FRC) allows reduction in, or substitution of, steel-bars to reinforce concrete and led to the commonly named structural FRC, with steel fibres being the most widespread. Macro-polymer fibres are an alternative to steel fibres, being the main benefits: chemical stability and lower weight for analogous residual strengths of polyolefin-fibre-reinforced concrete (PFRC). Furthermore, polyolefin fibres offer additional advantages such as safe-handling, low pump-wear, light weight in transport and storage, and an absence of corrosion. Other studies have also revealed environmental benefits. After 30 years of research and practice, there remains a need to review the opportunities that such a type of fibre may provide for structural FRC. This study seeks to show the advances and future challenges of use of these polyolefin fibres and summarise the main properties obtained in both fresh and hardened states of PFRC, focussing on the residual strengths obtained from flexural tensile tests.

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Recent advances in structural fibre-reinforced concrete focused on polyolefin-based macro-synthetic fibres

The use of polyolefin fibre reinforced concrete (PFRC) as an alternative for reducing the reinforcing steel bars employed in reinforced concrete has become real in the past years. This contribution analyses the improvements in sustainability that a change in the aforementioned reinforcement configuration might provide in a flyover bridge. Economic, environmental and social parameters of both possibilities were studied by means of the integrated value model for sustainable assessment. Such model, which acronym is MIVES (Modelo Integrado de Valor para una Evaluacion Sostenible, MIVES), is a multi-criteria decision-making method based on the value function concept and the seminars delivered by experts. The results of the MIVES method showed that the use of PFRC in combination with reinforced concrete (RC) has a sustainability index 22% higher. An analysis of the parameters that form this evaluation shows that there are no remarkable differences in the financial costs between the two possibilities studied. Nevertheless, social and environmental aspects provide with a better qualification the option of building a bridge by using PFRC combined with RC.

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Marino Rivera

Papers

Can Polyolefin Fibre Reinforced Concrete Improve the Sustainability of a Flyover Bridge