Demolished concretes recycling by the use of pneumatic jigs

Sampaio, Carlos Hoffmann; Cazacliu, Bogdan; Ambrós, Weslei Monteiro; Kronbauer, Márcio André; Tubino, Rejane Maria Candiota; Molin, Denise C. Dal; Oliva, Josep; Miltzarek, Gerson Luis; Waskow, Régis Pereira; Santos, Viviane Lg dos

doi:10.1177/0734242x20902835

Cited by 4 publications

(3 citation statements)

References 21 publications

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“…The jig presented three products: top layer (light particles), middle layer (mixture of light and dense particles), and bottom layer (denser particles). The results were published by Sampaio et al [30] and present the following results.…”

Section: Concentration In Water Jigssupporting

confidence: 54%

Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

et al. 2021

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This paper presents a physical characterization for the recycling into new concretes of three comminuted concretes: C16/20 (“ordinary concrete”), C50/60 (“high strength concrete”), and C70/85 (“very high strength concrete”). The top size of the crushed concretes was 19.1 mm and the size range was 4.75 to 19.1 mm. The characterization was carried out with coarse aggregate liberation, to be prepared and concentrated in a gravity concentration process. The density distribution of the coarse aggregate, cement paste, and sand was carried out in different size ranges (4.75/19.1 mm; 4.75/8.0 mm; 8.0/12.5 mm; and 12.5/19.1 mm) for the three concretes studied. The form factor of the samples, as well as the porosity determination of particles in different density ranges, are presented. The obtained results indicate that the coarse aggregate liberation was more intensive for the low resistance concrete (C16/20), but a reasonable coarse aggregate recovery is possible for all concretes.

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Section: Concentration In Water Jigssupporting

confidence: 54%

Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

et al. 2021

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“…The compressive strength of EPUC is 58.5 MPa~61.2 MPa, while the average density is 1768.5 kg/m 3 and the average compressive strength is 59.7 MPa. By comparison, it is found that, while EPUC meets the strength level of C50 concrete, its density is only 70% [26]. The average compressive strength of the six groups of specimens was taken to draw the stress-strain curve, as shown in Figure 9.…”

Section: Mechanical Properties (1) Compression Propertiesmentioning

confidence: 99%

Preparation and Mechanical-Fatigue Properties of Elastic Polyurethane Concrete Composites

Jia

Sun

et al. 2021

Materials

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In order to solve issues related to bridge girders, expansion devices and road surfaces, as well as other structures that are prone to fatigue failure, a kind of fatigue-resistant elastic polyurethane concrete (EPUC) was obtained by adding waste rubber particles (40 mesh with 10% fine aggregate volume replacement rate) to conventional engineering polyurethane concrete (PUC). Based on the preparation and properties of EPUC, its constitutive relation was proposed through compression and tensile tests; then, a scanning electron microscope (SEM), an atomic force microscope (AFM) and a 3D non-contact surface profilometer were used to study the failure morphology and micromechanisms of EPUC. On this basis, four-point bending fatigue tests of EPUC were carried out at different temperature levels (−20 °C, 0 °C, 20 °C) and different strain levels (400 με~1200 με). These were used to analyze the stiffness modulus, hysteresis angle and dissipated energy of EPUC, and our results outline the fatigue life prediction models of EPUC at different temperatures. The results show that the addition of rubber particles fills the interior of EPUC with tiny elastic structures and effectively optimizes the interface bonding between aggregate and polyurethane. In addition, EPUC has good mechanical properties and excellent fatigue resistance; the fatigue life of EPUC at a room temperature of 600 με can grow by more than two million times, and it also has a longer service life and reduced disease frequency, as well as fewer maintenance requirements. This paper will provide a theoretical and design basis for the fatigue resistance design and engineering application of building materials. Meanwhile, the new EPUC material has broad application potential in terms of roads, bridges and green buildings.

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“…Hence, the operational and maintenance expenses associated with dust removal (alongside the necessary accessories for dry jigging systems) can become the most significant costs in a CDW recycling facility [113]. Secondly, the efficiency constraints associated with density separation in air (as discussed in Section 3) typically restrict the effectiveness of dry jigging when undertaking more precise processing tasks, such as separating recycled concretes based on their attached mortar content or their strength classes [123].…”

Section: Construction and Demolition Wastes (Cdw)mentioning

confidence: 99%

Gravity Concentration in Urban Mining Applications—A Review

Ambrós

2023

Recycling

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Urban mining has emerged as a concept that goes beyond conventional recycling, as it aims to tackle both the challenges of solid waste generation and management, as well as the scarcity of primary resources. Gravity concentration has gained increasing attention as a promising method for addressing crucial challenges in urban mining applications. In this sense, this review provides a comprehensive and up-to-date overview of gravity concentration in urban mining processes, covering principles, techniques, current applications, recent advancements, challenges, and opportunities. Emphasis was placed on shifting from the commonly found literature focus on ore processing to solid waste processing. Three types of solid waste, namely plastics, construction and demolition waste (CDW), and waste from electrical and electronic equipment (WEEE), were chosen for a more in-depth examination due to their massive production and widespread generation. Discussions also considered the potential of gravity concentration to address the unique challenges in their processing and explored possibilities for future developments.

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Demolished concretes recycling by the use of pneumatic jigs

Cited by 4 publications

References 21 publications

Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

Characterization of Demolished Concretes with Three Different Strengths for Recycling as Coarse Aggregate

Preparation and Mechanical-Fatigue Properties of Elastic Polyurethane Concrete Composites

Gravity Concentration in Urban Mining Applications—A Review

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