• Collery, David J.
• Mckenna, Philip
• Paine, Kevin A.
• Dunne, David

Abstract

The recycling of construction, demolition and excavation waste (CDEW) makes it inevitable that a sand-like by-product is generated during the crushing and screening processes when producing coarse recycled aggregate. It is estimated that between 25 and 50% of initial CDEW after processing can be classified as fines, depending on the type, source and quality of the CDEW.Recycled aggregate fines (RAF) have an uncertain composition because of their sources, along with a potentially high clay and gypsum content.Given the possible multiple sources of RAF, it is vital to assess their suitability for use in concrete with respect to both engineering properties and environmental impact.However, as recycling technology continues to improve with a greater number of washing and recovery plants available along with improved site waste management plans, the potential for the use of RAF in concrete as sand replacement has increase significantly. This paper explores the use of RAF as a natural sand replacement in concrete.The paper aims to help increase the sustainable use of recycled aggregate fines within the construction industry by highlighting the benefits and constraints of using these materials. The paper will conclude with practical examples on the use of RAF in concrete applications. <br/>

Topics

• impedance spectroscopy
• strength
• washing
• gypsum