Production of the recycled coarse aggregate from concrete scraps

Aoki, Takahiro; Araki, J.; Maeda, S.; Iizasa, S.; Wang, D.; Shigeishi, Mitsuhiro; Namihira, T.; Ohtsu, Masayasu; Akiyama, H.

doi:10.1049/cp.2009.1640

Cited by 3 publications

(4 citation statements)

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“…and 31.5 -37.5 mm (data not shown). Based on the experimental fact that the gap distance plays a vital role on the percentages of energy transferred to particles (Aoki et al, 2009), it can be concluded that the varying gap distance within a particular size fraction (see Figure 4.1) will undoubtedly result in varying energy inputs to different particles. As a consequence, all SP tests were conducted based on varying gaps in this study, with each gap distance setting as close to the smallest axis of particle as possible to ensure same energy loading into every single particle.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, environmental concerns are minimised as the fragmentation process was carried out in water and less fines were generated. HVP coarse liberation has also been applied for recycling coarse aggregate from concrete scraps (Akiyama et al, 2007;Aoki et al, 2009;Araki et al, 2009;Inoue et al, 2009;Narahara et al, 2007;Touzé et al, 2017). It was found that the concrete liberates along the aggregates boundary, and the mechanical strength of the aggregates is not comprised (see Figure 2.17).…”

Section: Liberationmentioning

confidence: 99%

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Selective breakage of mineralised particles by high voltage pulses

Li¹

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Section: Methodsmentioning

confidence: 99%

Section: Liberationmentioning

confidence: 99%

Selective breakage of mineralised particles by high voltage pulses

Li¹

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“…A number of studies which investigated the feasibility of liberating concrete with electrical comminution for the recycling purposes have been reported ( (Bluhm et al, 1997;Bluhm et al, 2000;Fujita et al, 2001a;Frey et al, 2002;Aoki et al, 2009;Araki et al, 2009;Inoue et al, 2009;Wang et al, 2009;Menard et al, 2011). This paper applies the same technique for a different purpose -to study the effect of electrical breakdown channel locality.…”

Section: Synthetic Samplesmentioning

confidence: 99%

“…In both of these two comminution methods, tensile stress is the component predominating in the disintegration process. As a result concrete grout can also be used to model rock like behaviour in electrical comminution.The applicability to disintegrate concrete particles with electrical comminution had also been confirmed by a series of studies which aims to investigate the feasibility to liberate concrete with electrical comminution for recycling purpose (Bluhm et al, 1997;Bluhm et al, 2000; Chapter 3 Experimental Details 44 2001a; Frey et al, 2002;Aoki et al, 2009;Araki et al, 2009;Inoue et al, 2009;Wang et al, 2009;Menard et al, 2011). …”

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confidence: 95%

A study of the applications and modelling of high voltage pulse comminution for mineral ores

Zuo¹

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The pre-treatment of ore particles by high voltage pulses (HVP) at low specific energy has a potential to reduce the energy consumption and operation costs. Nevertheless, the influencing factors and the behavior of HVP breakage of ore particles have not yet been fully understood. The overall objective of this thesis is to study the applications and modelling of HVP breakage by understanding the behaviour of ore particles subjected to pulse discharge. The three areas investigated are:1)The effects of mineral properties on HVP selective breakage and the application of this selective breakage in ore pre-concentration.2) The methods to evaluate and to characterize HVP breakage results. 3)Modelling ore particle behavior in HVP breakage.In this project, the selectivity of HVP breakage is studied using synthetic samples made of construction grout and pyrite grains. The result confirms that the breakage response of particles is dominated by the locality of electrical breakdown channel. The electrical breakdown channel locality is controlled by the grains of minerals with high conductivity/permittivity and their location in a particle. This understanding has led to the discovery of a novel technique for ore preconcentration using high voltage electrical pulses. The technique utilises metalliferous graininduced selective breakage, under a controlled pulse energy loading, and size-based screening to separate the feed ore into two products for splitting of ores by grade.To evaluate HVP breakage results, a t 10 -based model was developed to predict the degree of impact breakage, t 10 , of pulse-treated particles from that of untreated particles. This model incorporates only one parameter, C Ab , which is equivalent to percentage change of A×b values. The t 10 -based model can be used to assess energy reduction due to the pre-weakening effect in the downstream mechanical comminution process. A Wide-size JKRBT characterisation method was created, initially for quick determination of breakage characteristics of the HVP product; ultimately for use as an express ore breakage characterisation method. In this method, particles in wide size range are tested as one size class in the JKRBT by single-particle breakage mode, significantly simplifying the feed particles preparing and product sizing procedures. A conceptual design of an on-line ore ii competence measuring system based on this principle is proposed. Both the t10-based model and the Wide-size JKRBT method utilise a size-dependent breakage model previously developed by the JKMRC.Behaviour of ore particles in HVP breakage was investigated with a pilot scale and a laboratory scale HVP breakage devices. The effects of specific energy, pulse voltage, cumulative discharges, feed particle size and ore particle breakage pattern (body breakage or surface breakage) were investigated. Based on the data, a model structure for HVP breakage was developed, which incorporates four sub-models using the similar structure to predict four HVP breakage indices: body breakage probability...

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