Effect of wind turbine blade waste on cement hydration and gel structure: Competitive interaction of glass and polyester resin

: With the rapid expansion of wind energy infrastructure, managing wind turbine blade waste (WTBW) has become an increasing environmental concern. This study explores the potential use of WTBW as a partial cement replacement to understand its influence on the reaction process, reaction products, and gel structure of cementitious composites. The alkali dissolution behavior of WTBW was investigated under different pH conditions, while isothermal calorimetry was used to monitor early hydration. The gel structure was characterized using 29 Si and 27 Al Nuclear Magnetic Resonance (NMR), and the resulting pore morphology and microstructure was visualized using X-ray Computed Tomography (XCT). Results revealed a critical competing mechanism between the glass and resin components of waste. At 5 wt.% replacement, the glass content contributed to the release of Si(OH) 4 and Al(OH)– 4 species, promoting a more complex and extended C–(A)–S–H gel network and improved pore structure. However, the polyester resin in WTBW hindered early hydration beyond 5 wt.% by consuming hydroxide ions, reducing pore solution pH, and releasing inhibitory glycol and carboxylate salts. In contrast, the pozzolanic activity of glass promotes gel formation, potentially offsetting the negative effects of the resin and offering a long-term performance enhancement.