Title: New Views on Effect of Recycled Aggregates on Concrete Compressive Strength

Author(s): Vivian A. Ulloa, Emili García-Taengua, María-José Pelufo, Alberto Domingo, and Pedro Serna

Publication: Materials Journal

Volume: 110

Issue: 6

Appears on pages(s): 687-696

Keywords: compressive strength; mid-term evolution; recycled aggregates; variability

DOI: 10.14359/51686336

Date: 11/1/2013

Abstract:
This paper presents an in-depth study on the effect that composition and properties of recycled coarse aggregates from previous concrete structures, together with water/cement ratio (w/c) and a replacement ratio of coarse aggregate, have on compressive strength, its evolution through time, and its variability. A rigorous approach through statistical inference based on multiple linear regression has identified the key factors. A predictive equation is given for compressive strength when recycled coarse aggregates are used. The w/c and replacement ratio are the capital factors affecting concrete compressive strength. Their effect is significantly modified by the properties and composition of the recycled aggregates used. An equation that accurately predicts concrete compressive strength in terms of these parameters is presented. Particular attention has been paid to the complex effect that old concrete and adhered mortar have on concrete compressive strength and its mid-term evolution. It has been confirmed that the presence of contaminants tends to increase variability of compressive strength values.