Limestone waste recycling for low-carbon high-performance concrete

Abstract

Large volumes of Construction and Demolition Waste, Excavated Waste limestone, Quarry Waste generated in the construction industry, present significant challenges in disposal with environmental impacts. Recycling presents opportunities in reducing the disposal of waste material and also resulting in lower demands on the extraction of new resources. However lowquality inert waste, which is generated in construction activities, presents limited opportunity in recycling, resulting in large volume of waste disposal. The project refers to the recycling of large volumes of excavation waste consisting primarily of lower quality limestone and other materials, normally considered inadequate if used as aggregate in civil engineering applications, primarily due to low mechanical characteristics and impurities. The Environment & Resources Authority reports that Malta alone generates about 1.5 million tonnes of C&D waste annually, which occupies almost 80% of the total waste generated in Malta (Environment & Resources Authority, 2021). Furthermore, cement as binder in concrete contributes significantly to greenhouse gases, responsible for approximately 8% of global CO2 emissions. [excerpt]