E-type Glass Fiber-Reinforced Polymer (GFRP) incorporated to concrete can degrade under alkaline environments. The alkali resistance of concrete containing 10% by volume of different fractions of wind turbine Blade Waste (BW), mainly composed of E-type GFRP, is therefore evaluated. For that, concrete mixes were immersed in a 1 N NaOH solution at temperatures of 80 °C and 300 °C, their variations in length and mechanical strength being assessed. Results revealed that BW promoted concrete expansion, although always within regulatory limits, as the maximum expansion was 0.0331% when adding BW sized lower than 1 mm. Alkali exposition also reduced strength by 10% on average. 1–2 mm BW provided the highest strength after alkali exposure, while BW larger than 2 mm provided load-bearing capacity. Scanning electron microscopy showed surface damage of BW components, which may be linked to such results. Overall, concrete containing BW showed limited expansion under alkali environments while providing proper mechanical performance.
