Characterization and influence of fine recycled aggregates on masonry mortars properties

Abstract

This research aims to study mechanical behaviour and relevant properties of masonry mortars fabricated using fine recycled aggregate in different mixture proportions. Fine recycled aggregates samples originated from the ceramic and concrete recycling process and coming from two recycling plants of Madrid region have been used. Tests were performed using 1:3:0.5 volumetric cement-to-aggregate-to-water ratio. Standardized sand with fine recycled aggregate replacement percentages were: 10%, 15%, 25%, 35% and 45%.A continuous size distribution curve can be observed and the main crystalline phases determined have been quartz, calcite and gypsum. Compressive strength, shrinkage and bond strength tests revealed poorer performance of recycled mortars compared to the conventional mortars; however, specific values are within the limits established by the manufacturers and standards. This study shows that cement-based mortars prepared with volumetric ratio 1:3:0.5 may contain up to 45% of fine recycled aggregates, without their properties being affected and without presenting significant losses. RESUMEN: Caracterización e influencia del arido reciclado fino en las propiedades de los morteros de albañilería.Esta investigación estudia el comportamiento mecánico y las propiedades más relevantes de los morteros de albañilería fabricados usando arenas recicladas en diferentes proporciones. Muestras pertenecientes a la línea de reciclaje cerámica y de hormigón proceden de dos centrales de reciclaje de la Comunidad de Madrid. Los ensayos se realizaron con una dosificación 1:3:0,5. Los porcentajes de arena reciclada fueron: 10%, 15%, 25%, 35% y 45%.Se observa una línea granulométrica continua y las principales fases cristalinas encontradas son cuarzo, calcita y yeso. Los ensayos de resistencia a compresión, retracción y adherencia muestran un peor comportamiento en los morteros reciclados frente a los morteros elaborados con arena normalizada, aunque dentro de los límites establecidos por normativas y fabricantes. Se deduce que, los morteros de albañilería base cemento, pueden incorporar un 45% de arena reciclada con una dosificación 1:3:0,5 sin que las propiedades ensayadas se vean afectadas con pérdidas significativas de prestaciones.

Study of recycled concrete aggregate quality and its relationship with recycled concrete compressive strength using database analysis

“…With regards to original waste, a high quantity of impurities (especially ceramic material) will increase water absorption (179). However, once again, the influence of the original concrete is not clear, with some researchers indicating that high grade original concrete can make water absorption lower (64,105) while others (26,108) state that the water absorption of recycled aggregates increases as the original concrete strength increases.…”

Study of potential advantages of pre-soaking on the properties of pre-cast concrete made with recycled coarse aggregate

“…The water absorption values of concrete made with RCA using different pre-soaking methods (Series [1][2][3][4][5] show that the values of all samples tested are within limits, and there are no significant differences between the different pre-soaking methods (Figures 2 and 7). However, differences are observed when the water absorption values of the series manufactured with NCA (Series C) and with RCA (Series 0-5) are compared, as discussed below (Table 5).…”

“…However, C&DW can be treated in appropriate industrial facilities to produce recycled aggregate (RA) that can be used to replace natural aggregate (NA) (2). For example, road construction (3), masonry mortar (4,5), structural and non-structural concrete (6,7), and even in pre-cast concrete products such as paving blocks (8), paving flags (9), kerbs (10) or partition wall blocks (11).…”

Uso de agregado miúdo reciclado em matrizes cimentícias para compósitos reforçados com fibras de sisal

“…A maior quantidade de finos, maior absorção e uma superfície mais rugosa do grão estão entre as principais características do agregado reciclado, em comparação com o agregado natural, que afetam a reologia da argamassa no estado fresco [14] e reduzem a sua consistên-cia. Saiz-Martínez et al [27] indica que o aumento do teor de superplastificante ou o ajuste do teor de água da mistura podem contribuir para a obtenção de uma trabalhabilidade adequada. O aumento do teor de aditivo, para 30,86 kg/m3, foi usado na matriz com 20% de agregado reciclado, como mostra a Tabela 2, para que todas as matrizes atingissem o espalhamento desejado.…”