Recycling fresh concrete waste: A review

Wang, Ruixuan; Zhang, Y. X.

doi:10.1002/suco.201800057

Cited by 33 publications

(18 citation statements)

References 48 publications

(182 reference statements)

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“…In recent years, a trend has been emerged to use concrete waste instead of natural resources in the production of concrete with the increase in consumption . The research results showed that the mechanical properties of recycled aggregate concrete (RAC) are generally lower than that of normal concrete (NC), but they are still sufficient for some practical applications in Civil Engineering …”

Section: Introductionmentioning

confidence: 99%

Mesomechanical properties of concrete with different shapes and replacement ratios of recycled aggregate based on base force element method

Wang

Peng

Kamel

2019

Structural Concrete

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In order to study the mesomechanical properties of recycled aggregate concrete (RAC) under uniaxial tension, a numerical model of RAC with two different aggregate shapes (circular and convex) and five different replacement ratios of recycled aggregate (0, 30, 50, 70, and 100%) was established. A new finite element method-base force element method (BFEM) was used to derive the element strain and the element stiffness matrix with an explicit expression without Gauss integral. The two-dimensional numerical model of the RAC was simulated to study the effect of aggregate shape, replacement ratio of recycled aggregate, aggregate distribution and interfacial transition zone (ITZ) properties on mesomechanical properties of RAC. Simulation results demonstrated that once the first crack appeared, the peak stress and peak strain were reached. The first crack appeared in old ITZ, which was located in whether the upper part or the lower part of the large-size recycled aggregate. The continuous cracks were mainly around the recycled aggregate and the aggregate concentrated area. Comparing with natural concrete, when the replacement ratio of recycled aggregate was 100%, the elastic modulus decreased by 16~25%, the peak stress decreased by 12~15%, and the peak strain changed slightly. The ITZ had a significant influence on the mechanical properties of RAC and must be considered in the analysis.

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Section: Introductionmentioning

confidence: 99%

Mesomechanical properties of concrete with different shapes and replacement ratios of recycled aggregate based on base force element method

Wang

Peng

Kamel

2019

Structural Concrete

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“…This recycled aggregate was used in concrete, with up to 30% replacement of the natural aggregates. However, this technique is significantly different from the other fresh concrete waste recycling techniques commonly reported in the literature [40][41][42].…”

Section: Introductionmentioning

confidence: 85%

Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate

et al. 2020

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Quarry aggregate reserves are depleting rapidly within Australia and the rest of the world due to an increasing demand for aggregates driven by expansion in construction. The annual production of premix concrete in Australia is approximately 30 million cubic meters, while 3–5% of concrete delivered to site remains unused and is disposed of in landfill or crushing plants. The production of coarse aggregates using this waste concrete is potentially a sustainable approach to reduce environmental and economic impact. A testing program has been conducted to investigate mechanical performance and permeation characteristics of concrete produced using a novel manufactured coarse aggregate recycled directly from fresh premix concrete. The recycled coarse aggregate (RCA) concrete satisfied the specified 28-day design strength of 25 MPa and 40 MPa at 28 days and a mean compressive strength of 60 MPa at 90 days. Aggregate grading was observed to determine strength development, while low water absorption, low drying shrinkage, and higher packing density indicate that the RCA concrete is a high-quality material with a dense pore structure. The rough fracture surface of the aggregate increased the bond between C-S-H gel matrix and RCA at the interfacial transition zone. Furthermore, a good correlation was observed between compressive strength and all other mechanical properties displayed by the quarried aggregate concrete. The application of design equations as stated in Australian standards were observed to provide a conservative design for RCA concrete structures based on the mechanical properties.

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“…Marco [13] found that the compressive strength of concrete mixed with waste slurry is slightly lower than that of concrete without waste slurry. Li, Xiao and others provided even more experimental results [14][15][16][17][18][19].…”

Section: Effects Of Waste Slurry On Mechanical Propertiesmentioning

confidence: 99%

“…The waste slurry is strongly alkaline, which gives play to the later activity of slag powder and produces stable hydration products. Many scholars [18][19][20][21] held that the concrete mixed with waste slurry is stronger than that mixed with tap water.…”

Section: Effects Of Waste Slurry On Microstructurementioning

confidence: 99%

Influence of Waste Slurry as Mixing Water on the Properties of C80 Concrete with Different Mineral Admixtures

Chen¹,

Tang²,

Zhuang³

2020

ACSM

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This paper mainly explores how waste slurry as mixing water affects the properties of C80 concrete. The waste slurry was collected from a mixing station. Two types of C80 concrete were prepared with different mineral admixtures: type I concrete mixed from 15% fly ash and 20% slag powder, and type II concrete mixed from 20% fly ash and 10% silica fume. The properties of the two types of concrete were evaluated in terms of working performance, mechanical properties, and durability. In addition, the influence of waste slurry on microstructure of concrete was analyzed through X-ray diffraction (XRD). The results show that, with the growing content of waste slurry, slump and expansion were declining; the initial and final setting times gradually increased, but the increments were not significant; with the growing content of waste slurry, the 7d compressive strength of type I concrete stayed below that of reference concrete, and gradually decreased, but the later compressive strengths increased rapidly; the 7d compressive strength of type II mineral admixture concrete gradually increased, while the later compressive strengths increased first and then decreased. Besides, the addition of waste slurry enhanced the resistance to chloride ion penetration (CIP), and increased the carbonization depth of concrete. The 7d XRD peak of using tap water as mixing water was slightly higher than that of using waste slurry as mixing water; the 28d XRD peak of the former was slightly lower than that of the latter. The research provides reference for applying waste slurry in concrete production.

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Recycling fresh concrete waste: A review

Cited by 33 publications

References 48 publications

Mesomechanical properties of concrete with different shapes and replacement ratios of recycled aggregate based on base force element method

Mesomechanical properties of concrete with different shapes and replacement ratios of recycled aggregate based on base force element method

Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate

Influence of Waste Slurry as Mixing Water on the Properties of C80 Concrete with Different Mineral Admixtures

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