Incorporating recycled concrete aggregate (RCA) is one way of recycling and using demolished concrete waste. However, it is an established fact that recycled concrete aggregates used without surface treatment/beneficiation exhibit inferior properties in comparison...
The presence of mortar has been reported as the main factor causing the lower quality of recycled concrete aggregates (RCA) when compared to natural aggregates (NA). A novel microwave-assisted technique to increase the quality of RCA by partially removing the mortar adhering to RCA particles and breaking up the lumps of mortar present in RCA is ...
In this paper, a comprehensive literature review was conducted on the utilization of recycled concrete aggregate (RCA), which is the dominant construction …
Input keywords were: recycled aggregate, concrete (or mortar), and sustainable construction. Based on this, 1580 documents were obtained, as indicated in Figure 1. Open in a separate window. Figure 1. Bibliometrics analysis of concrete containing recycled aggregate for the years 2013–2022.
The use of recycled concrete aggregate (RCA) from construction and demolition (C&D) waste is a rational way towards better sustainability in the construction industry.
The studies undertaken at the University of Cape Town (UCT) investigated the physical, chemical, and mineralogical properties of fine recycled concrete aggregate (FRCA), targeting methods of utilising and optimising FRCA properties using minimal beneficiation, and use of supplementary cementitious materials.
This study was also intended to enhance the strength and durability properties of concrete by using chemically and mechanically beneficiated recycled …
Highlights • Thermo-mechanical beneficiation process for crushed concrete. • Quality parameters and acceptance criteria for optimizing recycling. • Tuning of beneficiation based on process efficiency and aggregate quality. • Yield of high-quality …
In this paper, a novel process for the thermomechanical beneficiation of waste concrete for recycling is proposed through directly heating concrete chunks to …
The literature on recycling demolished concrete as aggregates is reviewed here. In all classes of concrete, 30% substitution of natural aggregate with coarse recycled concrete aggregate had only a moderate effect on concrete performance. By decreasing the water-to-cement ratio, higher replacement levels might …
Semantic Scholar extracted view of "Carbonation treatment of recycled concrete aggregate: Effect on transport properties and steel corrosion of recycled aggregate concrete" by Baojian Zhan et al.
The capability of the microwave assisted beneficiation of recycled concrete aggregate is experimentally investigated by Akbarnezhad. Microwave heating leads to significantly improvements in the properties of recycled concrete aggregate compared with other conventional beneficiation methods [33].
Physical characteristics of the coarse recycled aggregates were improved by adopting three different beneficiation techniques i.e. chemical beneficiation, mechanical beneficiation and chemical-mechanical beneficiation.
Thermomechanical Beneficiation of Recycled Concrete Aggregates (RCA) Thermomechanical Beneficiation of Recycled Concrete Aggregates (RCA) Post by: admin; July 21, 2023; Comments off; Categories: Previous post. Next post. Address. Building Technology, Construction Materials and Management (BTCM) Group
The use of recycled concrete aggregate (RCA) from construction and demolition (C&D) waste is a rational way towards better sustainability in the construction industry.
Recycled concrete aggregates (RCA) are produced by reducing the size of concrete debris through multiple crushing stages. Depending on the size, the crushed concrete particle may comprise one or more particles of natural coarse aggregate held together and surrounded fully or partially by a layer of mortar (Fig. 1a and b). In
The geometry of the attached mortar present in recycled concrete aggregates influences the behaviour of recycled aggregate concrete, since this mortar is porous, rough and tends to increase the elongation of aggregate particles.
Using recycled aggregates from construction and demolition waste can preserve natural aggregate resources, reduce demand of landfill, and contribute to sustainable built environment. This study provides a comprehensive review on recycled aggregate (RA) and recycled aggregate concrete (RAC) regarding their history, …
To achieve a good comparison basis, the cost, energy use and emissions incurred at the various stages of concrete recycling (including the beneficiation process) shall be estimated and compared with those of other alternative sources of aggregates.
Compared with traditional aggregate recycling methods, microwave heating-assisted concrete aggregate recycling was proposed as a new green technology. The secondary environmental pollution and the degree of mechanical damage caused by microwave assisted concrete recycling are low [10,11].
Recycled concrete aggregates (RCAs) have low quality when compared with natural or conventional aggregates as the paste adhering to it is the key aspect that affects its functionality. Since the adhering cementitious …
Preliminary laboratory investigation of thermally treated recycled concrete aggregate for general use in concrete; A. Akbarnezhad et al. Microwave-assisted beneficiation of recycled concrete aggregates
Due to the presence of old mortar (OM) and interfacial transition zone (ITZ), recycled concrete aggregate (RCA) is inferior to natural aggregate (NA). The purpose of this paper was to study the effect of accelerated carbonation on the macro-properties and micro-properties of RCA under different pressure (0.05, 0.15, 0.30 MPa). The macro …
The use of recycled coarse aggregates (RA) in concrete is a sustainable alternative to non-renewable natural aggregate (NA) to fabricate concrete products using …
In this paper, a comprehensive literature review was conducted on the utilization of recycled concrete aggregate (RCA), which is the dominant construction and demolition waste material, in base and subbase layers and its comparison with natural aggregate (NA).
The technique takes advan-tage of the difference in the electromagnetic properties of the adhering mortar and natural aggregates to generate high thermal stresses within the …
Carbonation resistance is an important factor affecting the durability of concrete, and the carbonation behavior of structural concrete become more complex under loading. In order to investigate the feasibility of utilizing Recycled Fine Aggregate (RFA) in structural concrete under a coupling of bending load and carbonation, two …
During the demolition and recycling process the specific surface area per volume of concrete is significantly increased. As a result, the potential for CO 2 absorption by carbonation of the cement hydrates is enhanced. In this study, recycled concrete aggregates (RCA) with varying moisture contents are carbonated with CO 2 at …
Recycled concrete aggregates (RCA) are often produced by crushing demolished concrete rubble in different steps using jaw and impacts crushers. …
Crushing demolition waste concrete to produce recycled aggregates for production of new concrete is one common means for achieving a more environmentally friendly concrete. In this paper, durability properties such as drying shrinkage, carbonation and long-term...
The main problem in using recycled concrete aggregate (RCA) as a construction material is due to the weak adhered mortar which usually has higher porosity and water absorption.
Aiming to increase the recycling rate on concrete formulation, the use of high quality recycled aggregates during recycling off-site or on-site is suggested. In this stage of recycling, gravity concentration by jigs and sensor-based sorting are used to separate different particles (2/20 mm) as bricks, tiles, gypsum and glass, previously ...
In the present work, the effects of accelerated carbonation on the physical and microstructural properties of recycled concrete fines are systematically studied. The RCF was prepared by crushing a base CEM I concrete mixture made in laboratory with a water-to-cement ratio of 0.54 and seal-cured for 28 days. The effects of CO2 …
Microwave assisted concrete recycling is highlighted by a large number of research groups all over the world due to its potential for significant process benefit. In this paper, systematic experiments are established to study the microwave heating and aggregate recycling of dried and saturated concrete, respectively, investigating the …
The presence of adhering cementitious mortar has been reported to be one of the main factors lowering the performance of concrete mixtures made with recycled concrete aggregates (RCA) when compared to natural aggregates (NA).
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