Fecha de publicación: -- Fuente: Materials The construction sector must simultaneously satisfy growing housing needs and lower its environmental impact. Compressed earth blocks (CEB) represent a promising low-carbon solution, but stabilization is typically required to ensure adequate strength and durability. This study evaluates recycled cement (RC), recovered from the cementitious fraction of construction and demolition waste (CDW), as a sustainable stabilizer for CEB, in comparison to ordinary Portland cement (OPC). Two cementitious fraction sources of RC were evaluated: pure cement paste (RCP) and concrete (RCC). Although the formulation with RC required more mixing water than the one with OPC, and consequently slightly reduced the CEB compactness, compressive strength losses remained below 30%. Microstructural analysis revealed that stabilization led to well-dispersed earth particles interposed with hydration products, with RC further refining the microstructure. Moreover, RC stabilized CEB achieved compressive and flexural strengths up to 2.7 and 3.2 times higher than unstabilized CEB. Water resistance tests confirmed that RC-added CEB withstood immersion, light rain and severe rainfall equivalent to centuries of natural exposure. The addition of RCC performed comparably to RCP since the aggregate content was properly accounted for, validating the separation process for industrial-scale use. These findings demonstrate that RC is a viable and eco-efficient alternative to OPC for CEB production, simultaneously promoting CDW valorization and the development of more sustainable and resilient building products.