Long-term analysis of the physical properties of the mixed recycled aggregate and their effect on the properties of mortars Ruan L. S. Ferreira a,⇑ , Marcos A. S. Anjos b,⇑ , Cinthia Maia c , Licarion Pinto d , Afonso R. G. de Azevedo e,⇑ , Jorge de Brito c a Federal Institute of Education, Science and Technology of Pernambuco, Civil Construction Department, 55200-000 Pesqueira, Brazil b Federal Institute of Education, Science and Technology of Paraíba, Civil Construction Department, 58015-435, João Pessoa, Brazil, and PEC at the Federal University of Rio Grande do Norte, 59078-970, Brazil c CERIS, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1, 1049-001 Lisbon, Portugal d Department of Fundamental Chemistry, Federal University of Pernambuco, 50.740-56 Recife, PE, Brazil e UFF - Federal Fluminense University, TER - Department of Agricultural and Environment Engineering, Rua Passo da Pátria, 156, 26354-051, Niteroi, RJ, Brazil highlights  The use of MRA for the production of cementitious materials is still limited.  First phase showed that there were no statistically differences in the physical properties of MRA over a year.  Feasibility of using MRA for the production of cementitious materials is correlated to the quality control of CDW.  The use of CDW is possible in eco-friendly mortars in buildings. article info Article history: Received 13 July 2020 Received in revised form 10 November 2020 Accepted 20 November 2020 Available online xxxx Keywords: Rendering mortars Construction and demolition waste Fine recycled aggregates Reproducibility Statistical analysis abstract The use of mixed recycled aggregates (MRA) for the production of cementitious materials is still limited due to the high heterogeneity of the rubble sources and the lack of specific regulations, which contributes to maintaining the problems associated with the management of construction and demolition waste (CDW) in recycling plants. Therefore, this paper investigates the influence and effects of the use of MRA, collected over time, on the physical and mechanical properties of cement and lime-based mortars, based on a statistical modelling using Machine Learning algorithms. For this purpose, an extensive exper- imental programme with three stages was developed, intending to evaluate the variability of the MRA produced. The first phase consisted of the physical characterization tests of 36 samples of MRA. The sec- ond phase intended to perform technological tests to select the best volumetric ratio of cement: hydrated-lime: MRA (1:1:6, 1:1:7 or 1:2:9) to be used with 100% MRA (modified mortars). Finally, the third experimental phase investigated the physical and mechanical properties of the modified mortars produced with the volume ratio selected in the previous phase and using MRA collected at different peri- ods of time. The results obtained were analysed using a T hypothesis test, a joint analysis of all variables using a Robust Principal Components Analysis (ROBPCA) and a partner recognition model based on data driven and ROBPCA (Data Driven Soft Independent Modelling of Class Analogy - DD-SIMCA). From the results, it was noticed that MRA 1:1:6 mortars presented a better performance in terms of mechanical strengths and water absorption by capillary, due to the filler effect of the MRA. As a matter of fact, the statistical tests have proven that no statistically significant differences were found in the physical prop- erties of the 36 MRA samples and among the physical and mechanical properties of mortars in these peri- ods investigated, which demonstrates the potentially reproducibility of CDW. Therefore, it was found that a proper selection and processing of CDW, as well as a definition of efficient mixing ratios can minimize the effects from the high heterogeneity of these wastes and enable the effective use of MRA in mortars. Ó 2020 Elsevier Ltd. All rights reserved. 1. Introduction Concerns about the management of construction and demoli- tion waste (CDW) by the construction industry have increased. https://doi.org/10.1016/j.conbuildmat.2020.121796 0950-0618/Ó 2020 Elsevier Ltd. All rights reserved. ⇑ Corresponding authors. E-mail addresses: ruan_landolfo@hotmail.com (R. L. S. Ferreira), marcos. alyssandro@gmail.com (M. A. S. Anjos), afonso.garcez91@gmail.com (A. R. G. de Azevedo). Construction and Building Materials xxx (xxxx) xxx Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat Please cite this article as: R. L. S. Ferreira, M. A. S. Anjos, C. Maia et al., Long-term analysis of the physical properties of the mixed recycled aggregate and their effect on the properties of mortars, Construction and Building Materials, https://doi.org/10.1016/j.conbuildmat.2020.121796