Concrete has played a pivotal role in shaping the modern world’s infrastructure and the built environment. Its unparalleled versatility, durability, and structural integrity have made it indispensable in the construction industry. From skyscrapers to long-span bridges, water reservoirs, dams, and highways, the ubiquitous presence of concrete in modern society underscores its significance in global development. As we stand at the crossroads of environmental awareness and the imperative to advance our societies, the sustainability of concrete production and utilization is becoming a new engineering paradigm. The immense demand for concrete, driven by urbanization and infrastructure development, has prompted a critical examination of its environmental impact. One of the most pressing concerns is the substantial carbon footprint associated with traditional concrete production. The production of cement, a key ingredient in concrete, is a notably energy-intensive process that releases a significant amount of carbon dioxide (CO2) into the atmosphere. As concrete remains unparalleled in its ability to provide structural functionality, disaster resilience, and containment of hazardous materials, the demand for concrete production is increasing, while at the same time, the industry is facing the urgency to mitigate its ecological consequences. This special publication investigates the multi-faceted realm of concrete sustainability, exploring the interplay between its engineering properties, environmental implications, and novel solutions, striving to provide an innovative and holistic perspective. In recent years, the concrete industry has witnessed a surge of innovation and research aimed at revolutionizing its sustainability. An array of cutting-edge technologies and methodologies has emerged, each offering promise in mitigating the environmental footprint of concrete. Notably, the integration of supplementary cementitious materials, such as calcined clays and other industrial byproducts, has gained traction to reduce cement content while enhancing concrete performance. Mix design optimization, coupled with advanced admixtures, further elevates the potential for creating durable, strong, and eco-friendly concrete mixtures. Concrete practitioners will gain an advanced understanding of a wide variety of strategies that are readily implementable and oftentimes associated with economic savings and durability enhancement from reading these manuscripts. The incorporation of recycled materials, such as crushed concrete and reclaimed aggregates, not only reduces waste but also lessens the demand for virgin resources. Furthermore, the adoption of efficient production techniques, along with the exploration of carbon capture and utilization technologies, presents an optimistic path forward for the industry. This special publication aspires to contribute to the ongoing discourse on concrete sustainability, offering insights, perspectives, and actionable pathways toward a more environmentally conscious future.

Due to a dynamic development of infrastructure, engineers around the world are looking for new materials and structural solutions, which could be more durable, cheaper in the life cycle management, and built quickly. One of prospective solutions for building small-span bridges can be precast lightweight concrete reinforced with glass fiber-reinforced polymer (GFRP) rebars. Thanks to prefabrication, it is possible to shorten the construction time. Using lightweight concrete affects structure weight as well as transportation costs. GFRP rebars can make the structure more durable and also cheaper in terms of life cycle management costs. The paper focuses on the fatigue performance of a real-scale arch (10.0 m (33 ft) long, 1.0 m (3.3 ft) wide, and 2.4 m (7.9 ft) high) made of lightweight concrete and GFRP rebars (LWC/GFRP) in comparison with an arch made of normal weight concrete and typical steel reinforcement (NWC/steel). The fatigue loads ranging from 12 to 120 kN (2.7 to 27 kip) were applied in a sinusoidal variable manner with a frequency of 1.5 Hz. This research revealed that the NWC/steel arch exhibited significantly better fatigue resistance when compared to the LWC/GFRP arch. Differences in the behavior of the NWC/steel and LWC/GFRP models under fatigue load were visible from the beginning of the research. The LWC/GFRP model was exposed to fatigue loads, resulting in gradual deterioration at an early stage. This degradation was evident through stiffness being progressively reduced, leading to increased displacements and strains as the number of load cycles increased. The model did not withstand the fatigue load and was destroyed after approximately 390 thousand load cycles, in contrast to the NWC/steel model, which withstood all 2 million load cycles without significant damages or the stiffness being decreased. However, the prefabricated lightweight concrete arches with composite reinforcement seem to be an interesting alternative of load-bearing elements in infrastructure construction.

Recent seismic events demonstrated the high vulnerability of existing reinforced concrete (RC) buildings. Lack of proper seismic details resulted in significant damage to structural components with many collapses and number of fatalities. The destruction of entire cities shield lights on the need of effective strengthening solutions that can be applicable at metropolitan/regional scale. They should be effective increasing significantly the seismic performance, affordable in the cost, fast to apply and with a low level of disruption to the occupants. This research work presents and discusses the preliminary results of an experimental programme on full-scale RC beam-column joints with reinforcement details typical of the existing buildings in the Mediterranean area. After assessing the response of the as-built specimen under a constant axial load and increasing cyclic displacement, a novel FRP-based strengthening system is presented. It combines the use of a quadriaxial CFRP fabric applied on the joint panel with CFRP spikes installed at the end of the beam and columns to improve the bond. The preliminary results pointed out the effectives of this strengthening solution in avoiding the joint panel shear failure and promoting a more ductile failure mode.

The seismic performance of reinforced concrete (RC) bridge columns subjected to multidirectional ground motions is a critical issue, as these columns can experience axial compression, bending, and torsional loading. Moreover, steel corrosion is a significant concern in existing bridges, leading to deficiencies in steel-RC structural members. The use of glass fiber-reinforced polymer (GFRP) reinforcement has been established as a practical and effective solution to mitigate the corrosion-related issues associated with traditional steel reinforcement in concrete structures. However, the dissimilar mechanical properties of GFRP and steel have raised apprehensions regarding its feasibility in seismic-resistant structures. The current study involves conducting an experimental investigation to assess the feasibility of utilizing GFRP reinforcement as a substitute for conventional steel reinforcement in circular RC bridge columns subjected to cyclic lateral loading, which induces shear, bending, and torsion. One column was reinforced with GFRP bars and stirrups, while the other column, served as a control and was reinforced with conventional steel reinforcement. The aim of this investigation was to analyze the lateral displacement deformability and energy dissipation characteristics of the GFRP-RC column. The results showed that GFRP-RC column exhibited stable post-peak behavior and high levels of deformability under the applied combined loading. Additionally, with a torsion-to-bending moment ratio of 0.2, both columns reached similar lateral load and torsional moment capacities and were able to attain lateral-drift capacities exceeding the minimum requirements of North American design codes and guidelines.

Fiber-reinforced polymer-reinforced concrete (FRP-RC) structures have won researchers’ attention for decades as a considerable substitute due to their superb mechanical and non-mechanical properties. Despite the promising potential of concrete structures with glass FRP and basalt FRP that were shown by previous research, there are few specifications for the seismic design of FRP-RC structures to date due to limited research data on their seismic behavior. This paper focuses on the seismic performance of concrete columns with carbon fiber-reinforced polymer (CFRP) reinforcement by finite element modeling. The effect of longitudinal reinforcement type and ratio, stirrup spacing, concrete strength and axial load ratio are included in the parametric analysis in VecTor2. Properly designed CFRP-RC columns with good confinement generally reach high load-carrying capacity and deformation level, while high axial load could induce relatively severe damage. To verify these conclusions, seven full-scale columns are under construction and will be tested under combined lateral reversed cyclic loading and constant axial loading.