Physical and mechanical characterization of concrete blocks with the incorporation of sand aggregate from construction waste

ABSTRACT

Due to the environmental problems generated by inadequate waste disposal, this work seeks to find an alternative for recycling construction waste (RCW). Among the possible applications, the recycled fine aggregate of RCW can be used as an alternative component in total or partial replacement to artificial sand in the cement mixtures designed for the production of the concrete blocks. Thus, this work aims to analyze the technical feasibility of the physical and mechanical aspects of the use of recycled fine aggregates for the production of concrete blocks for vertical panel systems. The reference trace 1:19.19 (cement: aggregates, by mass) was used in the dosage study, in which the industrial fine aggregate sand was progressively replaced by recycled construction waste sand. Substitutions were tested at 25, 50, and 100% of residue replacement. The physical and mechanical characteristics of reference and replacement concrete traces were evaluated according to Brazilian NBR 12118:2013 regulation. By the dosage study, it was sought to identify the dosage that incorporated the largest amount of residues in the mixture, maintaining the performance within the limits established by the regulation. The dosage with 50% incorporation displayed the best performance, with a water absorption content of 14.30% and average compressive strength of 4.13MPa. The 15x40 family concrete blocks, with dimensions of 140x190x390mm, produced with this dosage by the use of a Vibro press machine, displayed compressive strength characteristic of 3.21MPa and 9.89% of water absorption content, being classified as Class C, without structural function. Therefore, the construction waste aggregates are technically feasible to be incorporated into cementitious matrices for concrete block production, corroborating with urban sustainability.

Keywords
Recycled aggregate; Fine aggregate; Urban sustainability; Concrete blocks