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

Abstract

This work studies the physical and mechanical properties of recycled concrete aggregate (recycled aggregate from concrete waste) and their influence in structural recycled concrete compressive strength. For said purpose, a database has been developed with the experimental results of 152 works selected from over 250 international references.The processed database results indicate that the most sensitive properties of recycled aggregate quality are density and absorption. Moreover, the study analyses how the recycled aggregate (both percentage and quality) and the mixing procedure (pre-soaking or adding extra water) influence the recycled concrete strength of different categories (high or low water to cement ratios). When recycled aggregate absorption is low (under 5%), pre-soaking or adding extra water to avoid loss in workability will negatively affect concrete strength (due to the bleeding effect), whereas with high water absorption this does not occur and both of the aforementioned correcting methods can be accurately employed. RESUMEN: Estudio de la calidad del árido reciclado y su relación con la resistencia a compresión del hormigón reciclado utilizando una base de datos.El estudio analiza las propiedades físico-mecánicas de los áridos reciclados de hormigón (procedentes de residuos de hormigón) y su influencia en la resistencia a compresión del hormigón reciclado estructural. Para ello se ha desarrollado una base de datos con resultados de 152 trabajos seleccionados a partir de más de 250 referencias internacionales.Los resultados del tratamiento de la base indican que densidad y absorción son las propiedades más sensibles a la calidad del árido reciclado. Además, este estudio analiza cómo el árido reciclado (porcentaje y calidad) y el procedimiento de mezcla (presaturación o adición de agua extra) influyen en la resistencia del hormigón reciclado de diferentes categorías (alta o baja relación agua-cemento). Cuando la absorción es baja (inferior al 5%) presaturar o añadir agua para evitar pérdidas de trabajabilidad afectan negativamente a la resistencia (debido al bleeding), mientras que cuando es alta esto no sucede y ambos métodos son adecuados.

Evaluación del comportamiento mecánico de capas bituminosas ultra delgadas como una adecuada estrategia para la rehabilitación de pavimentos urbanos

“…Thus, the cumulative RDEC (Ratio of Dissipated Energy Change, Equation [1]) is used to analyze the development of the damage produced in the specimen, and the Mean Damage Parameter (γ) [2] is a value used to establish a reference for the resistance to fatigue cracking of the pavement (22). Where ω n is the energy dissipation produced in loading cycle n (in J/m 3 ); and ω n+1 is the energy dissipation in loading cycle n+1 (in J/m 3 ).…”

“…Over the last three decades, the volume of traffic in highway networks has notably increased (1). Nonetheless, in the field of construction engineering, sustainability issues have been of increasing concern (2). Therefore, the optimization of the maintenance activity of highway and road networks can be considered as a critical aspect to be solved.…”

Recycled concrete with coarse recycled aggregate. An overview and analysis

“…In order to produce RC, it is necessary to know the influence of the recycled aggregate's content and quality, which is usually determined by the aggregate's composition, water absorption capacity and attached mortar content (made of the source concrete) (9)(10)(11)(12)(13)(14)(15). These parameters lead to different sorts of recycled aggregates: recycled concrete aggregates (RCA), recycled ceramic aggregates or mixed recycled aggregates.…”

Influence of bagasse ash and recycled concrete aggregate on hardened properties of high-strength concrete

“…In addition, many researchers suggested that the using of RCA to replace NA had a negative effect on the durability of concrete (6)(7)(8)(9). As reported in the literature, the weakness and high porosity of recycled aggregate, which is poorer than crushed limestone (10)(11)(12), results in a lower quality concrete. However, recycled concrete can also be used as the aggregate for new concrete if its quality is been improved (12,13).…”

“…Many researchers have reported that the old cement paste and mortar attached to the surface of the original crushed aggregate greatly influence on the quality of RCA (10)(11)(12). Table 3 shows the physical properties for the crushed limestone and the RCA used in the research.…”