The rapidly growing volume of construction and demolition (C&D) waste produced by construction industry has led tremendous pressure on environmental protection. This study focuses on the improvement of the use of C&D waste as recycled fine aggregates (RFA) in cement composites by adding graphene oxide (GO), which is desirable to promote the application of recycled aggregates, decrease the exploitation of natural aggregates (NA) and alleviate environmental burden. In order to investigate the performance enhancement of RFA cement composites, the physico-chemical properties, microstructural performances, and environmental benefits of RFA mortars prepared with different GO contents (0.05 wt%, 0.1 wt%, and 0.2 wt%) have systematically examined. Electrochemical and mercury intrusive analysis revealed that the RFA mortars containing GO exhibited lower porosity and denser pore structure, compared to RFA mortars without any GO. The incorporated GO could further reduce ionic conductivity and thus improve the service life of RFA mortars. In addition, the interfacial transition zone (ITZ) between the RFA and cement paste was filled with hydration products when examined by scanning electron microscopy (SEM). Compared to those of RFA mortars without GO, the 28-day compressive and flexural strengths of RFA mortars with 0.2 wt% GO were increased by 19.2% and 47.5%, respectively. Finally, life cycle assessment (LCA) indicated that, compared to mortars with NA at the equivalent mechanical strengths, RFA mortars (containing 0.2 wt% GO) have better environmental performance (6.7% CO₂ emission reduction or 2.2% primary energy demand saving). Overall, the addition of GO could significantly improve the quality of RFA mortars, which could further apparently improve the recycling of C&D waste, and then promote the sustainable development of construction sector.

建筑业产生的拆建废物数量迅速增长，给环境保护带来了巨大压力。这项研究的重点是通过添加氧化石墨烯（GO）来改善C＆D废物在水泥复合材料中作为可回收细骨料（RFA）的用途，这对于促进可回收骨料的应用，减少对天然骨料（NA）的利用是理想的。并减轻环境负担。为了研究RFA水泥复合材料的性能增强，系统地研究了用不同GO含量（0.05 wt％，0.1 wt％和0.2 wt％）制备的RFA砂浆的理化性能，微观结构性能和环境效益。电化学和汞侵入分析表明，与不含GO的RFA砂浆相比，含GO的RFA砂浆显示出较低的孔隙率和较致密的孔结构。掺入的GO可以进一步降低离子电导率，从而提高RFA砂浆的使用寿命。此外，当通过扫描电子显微镜（SEM）检查时，RFA和水泥浆之间的界面过渡区（ITZ）充满了水合产物。与不使用GO的RFA砂浆相比，使用0.2 wt％GO的RFA砂浆的28天抗压强度和弯曲强度分别提高了19.2％和47.5％。最后，生命周期评估（LCA）表明，与具有相同机械强度的NA的砂浆相比，RFA砂浆（包含0.2 wt％的GO）具有更好的环保性能（6.7％的CO）掺入的GO可以进一步降低离子电导率，从而提高RFA砂浆的使用寿命。此外，当通过扫描电子显微镜（SEM）检查时，RFA和水泥浆之间的界面过渡区（ITZ）充满了水合产物。与不使用GO的RFA砂浆相比，使用0.2 wt％GO的RFA砂浆的28天抗压强度和弯曲强度分别提高了19.2％和47.5％。最后，生命周期评估（LCA）表明，与具有相同机械强度的NA的砂浆相比，RFA砂浆（包含0.2 wt％的GO）具有更好的环保性能（6.7％的CO）掺入的GO可以进一步降低离子电导率，从而提高RFA砂浆的使用寿命。此外，当通过扫描电子显微镜（SEM）检查时，RFA和水泥浆之间的界面过渡区（ITZ）充满了水合产物。与不使用GO的RFA砂浆相比，使用0.2 wt％GO的RFA砂浆的28天抗压强度和弯曲强度分别提高了19.2％和47.5％。最后，生命周期评估（LCA）表明，与具有相同机械强度的NA的砂浆相比，RFA砂浆（包含0.2 wt％的GO）具有更好的环保性能（6.7％的CO）当通过扫描电子显微镜（SEM）检查时，RFA和水泥浆之间的界面过渡区（ITZ）充满了水合产物。与不使用GO的RFA砂浆相比，使用0.2 wt％GO的RFA砂浆的28天抗压强度和弯曲强度分别提高了19.2％和47.5％。最后，生命周期评估（LCA）表明，与具有相同机械强度的NA的砂浆相比，RFA砂浆（包含0.2 wt％的GO）具有更好的环保性能（6.7％的CO）当通过扫描电子显微镜（SEM）检查时，RFA和水泥浆之间的界面过渡区（ITZ）充满了水合产物。与不使用GO的RFA砂浆相比，使用0.2 wt％GO的RFA砂浆的28天抗压强度和弯曲强度分别提高了19.2％和47.5％。最后，生命周期评估（LCA）表明，与具有相同机械强度的NA的砂浆相比，RFA砂浆（包含0.2 wt％的GO）具有更好的环保性能（6.7％的CO）₂减排或一次能源需求节省2.2％）。总体而言，添加GO可以显着改善RFA砂浆的质量，这可以进一步明显改善拆建废料的回收利用，从而促进建筑行业的可持续发展。