Performance analysis of mortars with mixed recycled aggregates from demolition waste

Análise de desempenho de argamassas com agregados reciclados mistos de resíduos de demolição

Given the generation of solid waste in the construction industry and its environmental impact, especially construction and demolition waste (CDW), it is necessary to seek sustainable alternatives for the sector. This study aims to analyze the performance of masonry and rendering mortars produced with mixed recycled aggregates from demolition waste, with the addition of lime and a plasticizing admixture. Ten mortar compositions were developed with different cement contents: 5 with lime, in the proportion 1:2:9 (cement: lime: sand), and 5 with plasticizing admixture (PA), in the proportion 1:3 (cement: sand). The tests of consistency index, specific mass, water absorption, tensile and compressive strength were the main tests performed as a basis for comparison. The results showed that mortars with recycled aggregates, especially when combined with PA and lower w/c ratios, presented better mechanical performance compared to the other compositions. In particular, the mortar composed entirely of recycled aggregate and PA exhibited higher mechanical strengths compared to compositions with natural aggregates, with increases in tensile strength ranging from 84% to 154%, and from 52% to 122% in compressive strength.

Keywords
Construction and demolition waste; Plasticizing admixture; Lime; Mortar