Alternative processing procedures for recycled aggregates in structural concrete

Pepe, Marco; Filho, Romildo Dias Toledo; Koenders, Eduardus; Martinelli, Enzo

doi:10.1016/j.conbuildmat.2014.06.084

Cited by 221 publications

(104 citation statements)

References 16 publications

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“…This method makes use the difference in the electromagnetic properties of the adhered mortar and natural aggregates. Pepe et al [6] used a rotating mill drum to process RCA. Aggregates collide each other while removing pieces of adhered mortar.…”

Section: Fig -1:typical Recycling Concrete Processmentioning

confidence: 99%

Assessment of Recycled Concrete Aggregate (Rca) Usage in Concrete

Ntaryamira¹,

Quansah²,

Yun-lian³

2017

IJRET

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Section: Fig -1:typical Recycling Concrete Processmentioning

confidence: 99%

Assessment of Recycled Concrete Aggregate (Rca) Usage in Concrete

Ntaryamira¹,

Quansah²,

Yun-lian³

2017

IJRET

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“…Various studies has been undertaken around the world to compare potential admixtures of recycled aggregate concrete (RAC) and their properties with natural aggregate concrete (NAC), for example [25], [26], [66] (Germany), [30] (UK), [34] (United Arab Emirates), [63] (Spain), [67] (Brazil), [68] (USA), [69] (India), [70] (China), [71] (Israel), [72] (Egypt), [73] (Portugal), [74] (Serbia), [75] (Finland) and [76] RA is the basic term, designating aggregate that contains varying proportions of RCA and RMA (RA = RCA + RMA). EU standards and related national specifications are oriented on these categories3 (see [75], [77], [78], [58]).…”

Section: Admixturementioning

confidence: 99%

Quantification of anthropogenic metabolism using spatially differentiated continuous MFA

Schiller¹,

Gruhler²,

Ortlepp³

2017

Change and Adaptation in Socio-Ecological Systems

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Coefficient-based, bottom-up material flow analysis is a suitable tool to quantify inflows, outflows and stock dynamics of materials used by societies, and thus can deliver strategic knowledge needed to develop circular economy policies. Anthropogenic stocks and flows are mostly of bulk nonmetallic mineral materials related to the construction, operation and demolition of buildings and infrastructures. Consequently, it is important to be able to quantify circulating construction materials to help estimate the mass of secondary materials which can be recovered such as recycled aggregates (RA) for fresh concrete in new buildings. Yet as such bulk materials are high volume but of low unit value, they are generally produced and consumed within a region. Loops are thus bounded not only by qualitative and technical restrictions but also spatially to within regions. This paper presents a regionalized continuous MFA (C-MFA) approach taking account of these restrictions of local consumption, quality standards and technical limitations, illustrated using the example of Germany. Outflows and inflows of stocks are quantified at county level and generalized by regional type, considering demand and supply for recycled materials. Qualitative and technical potentials of recycling loops are operationalized by defining coefficients to reflect waste management technologies and engineering standards. Results show that 48% of outflows of concrete and bricks are suitable for high-quality recycling, while 52% of outflows do not fulfill the quality requirement and must be recovered or disposed of elsewhere. The achievable inflow to RA is limited by the building activity as well as the requirements of the construction industry, e.g. the RA fraction of fresh concrete must not exceed 32%. In addition, there exist spatial disparities in construction across the country. In Germany, such disparities mean that there will be a shortfall in RA of 6.3 Gt by the year 2020, while the technically available but unusable RA (due to a regional mismatch of potential supply and demand) will total 3.2 Gt. Comprehensive recycling strategies have to combine high-quality recycling with other lower-grade applications for secondary raw materials. Particularly in the case of building materials, essential constraints are not only technical but also local conditions of construction and demolition. These interrelations should be identified and integrated into a comprehensive system to manage the social metabolism of materials in support of circular economy policies.

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“…However, during mechanical grinding recycled concrete aggregate could be damaged (micro -cracks by grinding). Autogenous cleaning [2] -with this process RCAs are placed in a rotating mill drum and collide against each other while removing pieces of attached mortar. The mill drum, 30 cm in diameter and 50 cm in depth (Figure 2), was filled up to 33% with ''raw'' recycled aggregates and the rotation rate was imposed to 60 rotations for minute.…”

Section: Mechanical Grindingmentioning

confidence: 99%

“…The European Directive n.98 of 19/11/2008 [1] calls on member states to take ''the necessary measures to promote the reuse of products and the preparing measures for re-use activities, particularly by promoting the establishment of economic tools and criteria about tenders, quantitative targets or other measures''. Particularly, it specifies that preparations for re-use, recycling and other types of recovery of material, including construction and demolition waste, shall be increased up to at least 70% (by weight) by 2020 [2]. Recycled Concrete Aggregate (RCA), derived from Concrete & Demolition waste generally consists of natural coarse aggregate and adhered mortar which makes it porous due to high mortar content, inhomogeneous and less dense [3,4].…”

Section: Introductionmentioning

confidence: 99%

Načini Poboljšanja Recikliranog Agregata – Pregledni Rad

Despotović¹

2016

Zbornik GFS

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Alternative processing procedures for recycled aggregates in structural concrete

Cited by 221 publications

References 16 publications

Assessment of Recycled Concrete Aggregate (Rca) Usage in Concrete

Assessment of Recycled Concrete Aggregate (Rca) Usage in Concrete

Quantification of anthropogenic metabolism using spatially differentiated continuous MFA

Načini Poboljšanja Recikliranog Agregata – Pregledni Rad

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