High-Performance Mortar with Epoxy-Coated Lightweight Aggregates for Marine Structures

Due to the global growth of the construction industry, the use of concrete has increased rapidly. Consequently, the depletion of natural aggregates, which are essential components of concrete, has emerged as a critical issue. Simultaneously, the construction of marine structures has recently increased due to population growth and climate change. This trend highlights the growing demand for durable and sustainable construction materials in aggressive environments. To address the depletion of natural aggregates, extensive research has focused on artificial lightweight aggregates produced from industrial waste. However, the high porosity and low compressive strength of artificial lightweight aggregates have limited their effectiveness in ensuring the performance of sustainable marine structures. In this study, a high-performance mortar (HPM) incorporating artificial lightweight fine aggregates (ALWFAs) was developed to address the depletion of natural aggregates and to serve as a protective layer material in marine environments. To enhance the physical properties of ALWFAs, the aggregates were coated with epoxy-TiO₂ coatings applied to both their internal voids and external surfaces. The effectiveness of this enhancement was assessed by comparing the performance of mortars prepared with uncoated and coated ALWFAs. The HPM was evaluated for its porosity, compressive strength, split tensile strength, and chloride diffusion coefficient. The results showed that increases in the ALWFA replacement ratio led to a general reduction in performance. However, a comparison between uncoated and coated ALWFAs revealed that the coated aggregates led to improvements of up to 4.13%, 49.3%, 28.6%, and 52.0% in porosity, compressive strength, split tensile strength, and chloride diffusion coefficient, respectively. The study results are discussed in detail in the paper.