Epoxy-based vitrimers represent a paradigm shift in material science, offering an unprecedented combination of mechanical robustness, environmental sustainability, and reconfigurability. These dynamic polymer systems utilize associative dynamic covalent bonds (DCBs) such as transesterification to blend the structural integrity of thermosets with the recyclability and self-healing properties of thermoplastics. This unique combination makes vitrimers ideal candidates for high-performance applications in industries such as civil engineering, where material durability, repairability, and environmental compatibility are critical. Epoxy-based vitrimers, in particular, exhibit exceptional self-healing capabilities, allowing them to autonomously repair microcracks and damage, restoring mechanical properties under appropriate stimuli such as heat or light. Their recyclability further aligns with global sustainability goals by reducing material waste and lifecycle costs. Recent advancements have also integrated bio-based feedstocks and scalable manufacturing methods, enhancing the feasibility of these materials for industrial applications. This review explores the underlying self-healing mechanisms, dynamic recycling processes, and the emerging role of epoxy-based vitrimers in civil engineering. Challenges related to scalability, mechanical optimization, and regulatory acceptance are also discussed, with a focus on their potential to drive sustainable innovation in infrastructure materials.

In this study, the effect of adding waste oyster shell powder (WOSP) on the strength and microstructure of cementitious composites was experimentally investigated. The test variables included the WOSP replacement ratios (0, 25, 50, and 75%) by weight of cement, the type of curing water (tap water and seawater), and the curing period (7, 28, 90, 180, and 365 d). The compressive strength, flexural strength, and initial and secondary sorptivity were measured at specific ages. Moreover, scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements were conducted, and their results were analyzed. Samples with WOSP replacement ratios greater than 25% exhibited a rapid reduction in measured strength values. The correlation between compressive strength and initial sorptivity tends to be slightly higher than that between flexural strength and initial sorptivity. The one-year investigation revealed that there was no significant effect of using different curing waters on strength development. The effect of the curing period was evident in enhancing the strength only in the early stages, with no significant increase in strength observed after 28 d. The XRD analysis revealed that most samples prepared with WOSP contained CaCO₃, and the peak of CaCO₃ tended to increase with an increasing WOSP replacement ratio. The SEM results revealed that a high replacement ratio of WOSP can have a negative influence on cement hydration and the pozzolanic effect. The limitations of this study and future work were also discussed.

In this study, chlorine-induced corrosion and blister formation on steel pipes (SPs) coated with modified polyethylene powder (MPP) were evaluated through various tests, including chlorine exposure, wet immersion, and temperature gradient experiments. The results confirmed that the extent of corrosion and iron leaching varied with the coating type as expected. In batch leaching tests, no corrosion was observed on modified polyethylene-coated steel pipes (MPCSPs) within a chlorine concentration range of 0 mg/L to 10 mg/L; similarly, there were no significant changes in specimen weight or iron levels. In contrast, the control group with uncoated SPs exhibited significant iron leaching and corrosion, a trend consistent in sequential leaching experiments. SEM analysis after a month of chlorine exposure revealed no significant corrosion on MPCSPs, and SEM-EDX confirmed no major changes in the carbon bond structure, indicating resistance to high chlorine concentrations. Comparative analysis of wet immersion and temperature gradient tests between MPCSP and conventional epoxy-coated SP (ECSP) specimens revealed that MPCSPs did not develop blisters even after 100 days of immersion, whereas ECSPs began showing blisters as early as 50 days. In temperature gradient tests, MPCSPs showed no blisters after 100 days, while ECSPs exhibited severe internal coating layer blisters.