Sustainable development requires a holistic perspective that integrates the different aspects of production and consumption and promotes the transition to a circular economy. This approach aims to balance the needs of the present and future generations, as well as the social, environmental, and economic dimensions of development. By producing products that are durable, recyclable, and reusable, and by minimizing the use of energy and materials, the environmental impact of production can be reduced while also generating economic benefits and enhancing social well-being. The article addresses the multicriteria sustainability of producing mortar modified with sand from recycled concrete rubble. The research explored the possibility of replacing natural sand with recycled sand in proportions from 10% to 100%. The consistency of mixtures, flexural and compressive strengths after 2, 28, and 90 days, as well as the carbon footprint and cost of the aggregate used were analyzed. The waste management index and sustainable use of natural resources were also considered. The research and analysis showed that recycled sand could be successfully used as an alternative for natural aggregate, as there are clear environmental and economic advantages, and the basic technical characteristics do not differ significantly statistically from the unmodified composite.