Recycled concrete with coarse recycled aggregate. An overview and analysis

Abstract

ABSTRACT:The construction field has contributed to environmental degradation, producing a high amount of construction and demolition waste (C&D waste) and consuming large volumes of natural resources. In this context, recycled concrete (RC) has been recognised as a means to preserve natural resources and reduce space for waste storage. During the last decades, many researchers have developed works studying different recycled concrete properties.This review focuses on structural RC made with coarse recycled aggregate from concrete waste. The main objective is to provide a state of the art report on RC's properties and an analysis on how to predict them taking into account relevant research works. Moreover, the study tries to collect and update RC findings, proposing equations to define RC's performance, in terms of mechanical strength, modulus of elasticity, stress-strain, creep and shrinkage. RESUMEN:Hormigón reciclado con árido grueso reciclado. Una visión general y análisis. El campo de la construcción ha contribuido a la degradación del medio ambiente, produciendo gran cantidad de residuos de construcción y demolición y consumiendo grandes volúmenes de recursos naturales. En este contexto, el hormigón reciclado se ha presentado como una opción para preservar los recursos naturales y reducir el espacio destinado a vertedero. Así, durante las últimas décadas, muchos investigadores han desarrollado trabajos para estudiar las propiedades del hormigón reciclado.Este artículo se centra en el hormigón estructural fabricado con árido reciclado grueso procedente de residuos de hormigón. El principal objetivo es desarrollar un estado del arte que recoja las principales propiedades del hormigón reciclado y un análisis de cómo calcularlas teniendo en cuenta un gran número de trabajos relevantes en este ámbito. Adicionalmente, el estudio recopila y actualiza el conocimiento sobre estos hormigones, proponiendo ecuaciones que permitan definir sus resistencias mecánicas, módulo de elasticidad, tensión-deformación, fluencia y retracción.

Base force element method based on the complementary energy principle for the damage analysis of recycled aggregate concrete

“…Previous studies have indicated that with an increasing replacement ratio the peak strain increases, and the ultimate strain may decrease or increase. According to References the peak strain and ultimate strain corresponded to a strain in the maximum stress ( f c ) and 0.6 f c in the descending part, respectively, as shown in Table .…”

“…Therefore, using recycled aggregate instead of natural aggregate has a positive influence on saving natural resources and protecting the environment. In recent years, recycled aggregate concrete (RAC), which is mixed with natural aggregate and recycled aggregate, has become a new topic of great concern in many countries . In this case, investigating and understanding the mechanical properties of RAC are critical to ensuring its successful application.…”

“…In addition to aggregates, new cement mortars, and new interfacial transition zones (New ITZs) between them, the RAC has two more mesophases compared with that of NAC: one is the old adhered mortar intrinsically clinging to the surfaces of recycled aggregates, and the second is the old ITZs between the old adhered mortars and the recycled aggregates. According to the macroscopic experimental and numerical simulation investigations, it is now accepted that under the same situations the mechanical properties of RAC are worse when compared with the NAC . The two major reasons for this are due to the effects by Equation (1) the recycled aggregate replacement ratios, and Equation (2) the thickness and properties of the old adhering mortar.…”

“…In recent years, recycled aggregate concrete (RAC), [42][43][44] which is mixed with natural aggregate and recycled aggregate, has become a new topic of great concern in many countries. 42,[45][46][47] In this case, investigating and understanding the mechanical properties of RAC are critical to ensuring its successful application.…”

“…According to the macroscopic experimental and numerical simulation investigations, it is now accepted that under the same situations the mechanical properties of RAC are worse when compared with the NAC. 41,42,45,50,51 The two major reasons for this are due to the effects by Equation (1) the recycled aggregate replacement ratios, and Equation (2) the thickness and properties of the old adhering mortar.…”