Análise mecânico-estrutural de blocos cimentícios de RCD: avaliação comparativa do impacto da variação dos traços de cimento

Abstract

The incorporation of Construction and Demolition Waste (CDW) into cementitious components is an alternative for reducing the consumption of natural raw materials and increasing the recovery of construction waste. This study evaluated the influence of volumetric cement content on the compressive strength of CDW cementitious blocks. Five experimental groups were produced with cement contents of 8.3%, 10.0%, 12.5%, 16.7%, and 20.83%, while the operating conditions of a semi-automatic press were kept constant. After 28 days of curing, prisms composed of four units were subjected to compression testing. The results were assessed through descriptive statistics, analysis of variance, and Tukey's test at a 5% significance level. The highest mean strength was obtained at 12.5% cement, reaching 1.10 MPa, followed by 16.7% and 10.0%, with 1.01 MPa and 0.96 MPa, respectively. The analysis of variance indicated a significant effect of cement content (p = 0.0088), and Tukey's test identified differences between the 8.3% group and the 12.5% and 16.7% groups. Increasing the cement content to 20.83% did not provide an additional strength gain. None of the formulations reached the mean limit of 2.0 MPa adopted as a reference for non-load-bearing soil-cement bricks. Under the evaluated conditions, the 12.5% content showed the best performance, while the findings demonstrated the need to improve particle packing and increase compaction energy before considering a structural application.