Advanced comminution of concretes with limestone filler to improve circularity of recycled aggregates

• Grant number: 23/08124-2
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: December 01, 2023
• End date: November 30, 2024
• Field of knowledge: Engineering - Civil Engineering - Construction Industry
• Principal Investigator: Sérgio Cirelli Angulo
• Grantee: Tatiane Isabel Hentges
• Supervisor: Holger Lieberwirth
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Technische Universität Bergakademie Freiberg (TU Bergakademie Freiberg), Germany
• Associated to the scholarship: 21/01351-8 - Formulation of concrete to remove adhered cement paste from recycled aggregate by comminution, BP.DR

Abstract

The concrete recycling methods produce recycled concrete aggregate (RCA) composed of an adhered cement paste, which elevates the aggregate's porosity and harms its use in new concretes. One strategy to increase RCA quality, or the complete recover (circularity) of cement and aggregates, is the adoption of limestone filler addition in cement matrix and test different comminution methodologies. High aggregate liberation has been obtained applying innovative comminution techniques in concrete waste, such as high voltage electric impulses. Next to this, the initial concrete formulation can also contribute to its recyclability. The presence of limestone filler, for example, tends to wider the strain, indicating changes in the fracture process zone of the material. In this way, this study proposes the use of the electric impulse and impact crush to recycle concretes with and without limestone filler, intending to obtain a recycled aggregate free of adhered cement mortar. The experimental program proposed is to analyze the recycled aggregates obtained from concretes with and without limestone filler after comminution. Two types of comminutions will be tested: electric impulse test rig and impact crusher. Then, the particles produced from the comminution will be analyzed by point load test. As a result, correlations will be made on concrete composition and type of comminution, particle size distribution, aggregate liberation, and mechanical properties of aggregate particles. At the end of this work, conclusions on the strategies to obtain a better-recycled aggregate will be made. (AU)