The sustainability of the construction sector demands the reduction of CO₂ emissions. The optimization of the amount of cement in concrete can be achieved either by partially replacing it by additions or by reducing the binder content. The present work aims at optimizing the properties of concrete used in the production of reinforced concrete poles for electrical distribution lines, combining the maximization of compactness with the partial replacement of cement by fly ash, natural pozzolans, and electric furnace slags. Natural aggregates were also partially replaced by recycled ones in mixtures with fly ash. Two types of concrete were studied: a fresh molded one with a dry consistency and a formwork molded one with a plastic consistency. The following properties were characterized: mechanical properties (flexural, tensile splitting, and compressive strengths, as well as Young’s modulus) and durability properties (capillary water absorption, water penetration depth under pressure, resistance to carbonation, chloride migration, and concrete surface resistivity). The service life of structures was estimated, taking the deterioration of reinforcement induced by concrete carbonation or chloride attack into account. Results revealed that mixtures with fly ash exhibit higher mechanical performance and mixtures with fly ash or pozzolans reveal much higher durability results than the full Portland cement-based mixtures.

Forest waste is globally abundant and holds significant potential for valorisation in various sectors. This paper investigates its use in urban road infrastructures, utilising enzymatic lignin, a by-product from forest waste bioethanol production, as a bitumen extender for warm-mix asphalt. Since this asphalt concrete is produced at about 40 °C below the traditional hot-mix asphalt temperature, this study evaluates lignin’s ability to ensure the required mechanical performance of asphalt concrete in both aged and non-aged states. The TEAGE—TEcnico accelerated AGEing device—applied UV radiation and wet/dry cycles to virgin bitumen, a lignin blend, and compacted asphalt concrete specimens to replicate urban weathering. Cylindrical specimens underwent indirect tensile tests to assess water sensitivity, while beam samples underwent four-point bending tests to evaluate stiffness and fatigue resistance. The results indicate that this warm-mix asphalt, with lower atmospheric emissions during manufacturing and pavement construction, meets the mechanical demands of urban roads, particularly with respect to fatigue and water resistance. However, the findings also show that asphalt concrete containing lignin experiences excessive ageing of small specimens, and further testing on compacted slabs is needed to better simulate exposure to UV radiation in pavement layers. Overall, the study concludes that lignin lowers asphalt production temperatures and partially substitutes conventional binders, with promising applications in urban pavement technologies.