Ordinary concrete is an indispensable construction material of modern society which is used for everything from mundane road pavements to building structures. However, it is often used for non-load-bearing applications (for instance, insulating lightweight building units) where mechanical strength is not a priority. This leads to an avoidable depletion of natural aggregates which could instead be replaced by alternative waste materials capable of conferring to the material the desired performance while ensuring a “green” route for their disposal. Furthermore, the automation of production processes via 3D printing can further assist in the achievement of a more advanced and sustainable scenario in the construction sector. In this work, performance and environmental analyses were conducted on a 3D-printable cementitious mix engineered with ground waste tire rubber aggregates. The research proposed a comparative study between rubberized concrete mixes obtained by 3D printing and traditional mold-casting methods to achieve a comprehensive analysis in terms of the mix design and manufacturing process. To evaluate the environmental performance (global warming potential and cumulative energy demand) of the investigated samples, Life Cycle Assessment models were built by using the SimaPro software and the Ecoinvent database. The Empathetic Added Sustainability Index, which includes mechanical strength, durability, thermo-acoustic insulation, and environmental indicators, was defined to quantify the overall performance of the samples in relation to their engineering properties and eco-footprint.

To move toward eco-sustainable and circular composites, one of the most effective solutions is to create thermoplastic composites. The strong commitment of world organizations in the field of safeguarding the planet has directed the research of these materials toward production processes with a lower environmental impact and a strong propensity to recycle the polymeric part. Under its chemical properties, Nylon 6 is the polymer that best satisfies this specific trade-off. The most common production processes that use a thermosetting matrix are described. Subsequently, the work aimed at investigating the use of thermoplastics in the same processes to obtain comparable performances with the materials that are currently used. Particular attention was given to the in situ anionic polymerization process of Nylon 6, starting from the ε-caprolactam monomer. The dependencies of the process parameters, such as temperature, time, pressure, humidity, and concentration of initiators and activators, were therefore investigated with reference to the vacuum infusion technique, currently optimized only to produce thermosetting matrix composites, but promising for the realization of thermoplastic matrix composite; this is the reason why we chose to focus our attention on the vacuum infusion. Finally, three production processes of the polymeric matrix and glass fiber composites were compared in terms of carbon footprint and cumulative energy demand (CED) through life-cycle assessment (LCA).

This study evaluates the durability of Self-Compacting Sand Concrete (SCSC) incorporating Windshield Glass Aggregate (WGA) as a sustainable replacement for natural sand, utilizing Blast Furnace Slag (BFS) as a constant filler component. Eleven mixtures were investigated: a control mix and ten variants with WGA substitution levels ranging from 10% to 100% in 10% increments. The specimens were exposed to elevated temperatures of 200–800 °C and to 240 freeze–thaw cycles between −18 °C and +9 °C. Under heating, mass loss increased with temperature, but WGA-rich mixtures generally showed lower mass loss and higher residual mechanical performance than the control. At 400 °C, WGA100 reached about 96 MPa in compressive strength and 15 MPa in flexural strength, corresponding to residual values of approximately 110.34% and 166.7%, respectively. After freeze–thaw cycling, all mixtures showed limited surface deterioration and mass loss below 1%, decreasing from about 0.76% for the control mixture to about 0.05% for WGA100. The improved durability is mainly attributed to the physical effect of WGA replacement and the baseline matrix refinement associated with BFS.