Corrigendum to “Influence of untreated coal and recycled aggregates on the mechanical properties of green concrete” [276 (2020) 124291]

Concrete made with large-size recycled aggregates is a new kind of recycled concrete, where the size of the recycled aggregate used is 25–80 mm, which is generally three times that of conventional aggregate. Thus, its composition and mechanical properties are different from that of conventional recycled concrete and can be applied in large-volume structures. In this study, recycled aggregate generated in two stages with randomly distributed gravels and mortar was used to replace the conventional recycled aggregate model, to observe the internal stress state and cracking of the large-size recycled aggregate. This paper also investigated the mechanical properties, such as the compressive strength, crack morphology, and stress–strain curve, of concrete with large-size recycled aggregates under different confining pressures and recycled aggregate incorporation ratios. Through this research, it was found that when compared with conventional concrete, under the confining pressure, the strength of large-size recycled aggregate concrete did not decrease significantly at the same stress state, moreover, the stiffness was increased. Confining pressure has a significant influence on the strength of large-size recycled aggregate cocrete.

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A Review on the Mechanical Properties of the Green Concrete

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1055/1/012012 ◽

2021 ◽

Vol 1055 (1) ◽

pp. 012012

Author(s):

T S Mukesh ◽

K Sampathkumar ◽

V Kisshore

Keyword(s):

Mechanical Properties ◽

Green Concrete

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Effect of mixed recycled aggregates on mechanical properties of recycled concrete

Magazine of Concrete Research ◽

10.1680/macr.14.00217 ◽

2015 ◽

Vol 67 (5) ◽

pp. 247-256 ◽

Cited By ~ 18

Author(s):

Desirée Rodríguez-Robles ◽

Julia García-González ◽

Andrés Juan-Valdés ◽

Julia Ma Morán-del Pozo ◽

M. Ignacio Guerra-Romero

Keyword(s):

Mechanical Properties ◽

Recycled Concrete ◽

Recycled Aggregates ◽

Mixed Recycled Aggregates

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Effect of Fly Ash on the Compressive Strength of Green Concrete

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.3499 ◽

2020 ◽

Vol 10 (3) ◽

pp. 5728-5731 ◽

Cited By ~ 3

Author(s):

S. A. Chandio ◽

B. A. Memon ◽

M. Oad ◽

F. A. Chandio ◽

M. U. Memon

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Recycled Aggregates ◽

Waste Materials ◽

Partial Replacement ◽

Equal Proportion ◽

Standard Size ◽

Green Concrete ◽

Coarse Aggregates ◽

Management Issues

This research paper aims at investigating the effects of fly ash as cement replacement in green concrete made with partial replacement of conventional coarse aggregates with coarse aggregates from demolishing waste. Green concrete developed with waste materials is an active area of research as it helps in reducing the waste management issues and protecting the environment. Six concrete mixes were prepared using 1:2:4 ratio and demolishing waste was used in equal proportion with conventional aggregates, whereas fly ash was used from 0%-10% with an increment of 2.5%. The water-cement ratio used was equal to 0.5. Out of these mixes, one mix was prepared with all conventional aggregates and was used as the control, and one mix with 0% fly ash had only conventional and recycled aggregates. The slump test of all mixes was determined. A total of 18 cylinders of standard size were prepared and cured for 28 days. After curing the compressive strength of the specimens was evaluated under gradually increasing load until failure. It is observed that 5% replacement of cement with fly ash and 50% recycled aggregates gives better results. With this level of dosage of two waste materials, the reduction in compressive strength is about 11%.

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MECHANICAL PROPERTIES OF RECYCLED AGGREGATE CONCRETE WITH STEEL FIBER: A REVIEW

Tikrit Journal of Engineering Sciences ◽

10.25130/tjes.26.3.05 ◽

2019 ◽

Vol 26 (3) ◽

pp. 37-42

Author(s):

Ashtar S. Al-Luhybi

Keyword(s):

Mechanical Properties ◽

Steel Fiber ◽

Recycled Aggregate Concrete ◽

Strength Characteristics ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Aggregate Concrete ◽

Building Process

In the building process, the recycling of aggregates arising from building and demolition debris is one of the best alternatives to maintain the environment and the areas needed to bury these debris. It also helps to preserve natural concrete sources from depletion efficiently. The use of recycled aggregates in new concrete manufacturing, however, leads to a decrease in concrete\\\’s strength characteristics. This reduction rises with the rise in the percentage of recycled aggregates used in concrete, which has caused many researchers to undertake many researches on how to enhance the characteristics of recycled aggregate-containing concrete. This paper presents several studies that examined the effect of adding steel fiber to improve the properties of concrete containing a coarse recycled aggregate.

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Studies on Hemp and Recycled Aggregate Concrete

International Journal of Concrete Structures and Materials ◽

10.1186/s40069-020-00429-6 ◽

2020 ◽

Vol 14 (1) ◽

Author(s):

Samer Ghosn ◽

Nour Cherkawi ◽

Bilal Hamad

Keyword(s):

Mechanical Properties ◽

Fiber Length ◽

Plain Concrete ◽

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Silane Treatment ◽

Hemp Fiber ◽

Fiber Treatment

Abstract This paper reports on the first phase of a multi-phase research program conducted at the American University of Beirut (AUB) on “Hemp and Recycled Aggregates Concrete” (HRAC). HRAC is a new sustainable concrete material where hemp fibers are incorporated in the mix, the coarse aggregate content is reduced by 20% of the concrete volume, and 50% of the natural coarse aggregates (NCA) are replaced by recycled concrete aggregates (RCA), thus saving on natural resources and addressing the problem of waste material disposal. The effect of the new material on concrete consistency and hardened mechanical properties was studied. Also, few durability tests were conducted. Variables included percentage replacement of NCA by RCA (0 or 50%), maximum size aggregate (10 or 20 mm), hemp fiber length (20 or 30 mm), and hemp fiber treatment (alkali or silane or acetyl). Fiber characterization tests were conducted including morphology, crystallinity, and thermal analysis. The tests indicated that alkali and acetyl fiber treatments were better than the silane treatment in removing impurities on the fiber surface. Also, alkali and acetyl treatments have increased the crystallinity of the fibers while silane treatment decreased it. Results of mechanical properties tests showed that while HRAC has considerable lower compressive strength and modulus of elasticity than plain concrete, the flexural strength and splitting tensile strength are not significantly affected. The flexural stress–strain behavior of HRAC is ductile as compared to the brittle behavior of the plain concrete beams indicating positive impact on toughness and energy dissipation. The durability tests indicated that whereas HRAC mixes have higher absorption than plain concrete, they have better thermal properties and their resistance to freeze–thaw cycles is comparable to plain concrete. All test results were not significantly affected by fiber length or fiber treatment.

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Investigation of the mechanical properties of concrete containing recycled aggregate and scrap crumb rubber and polypropylene fibers

Progress in Rubber Plastics and Recycling Technology ◽

10.1177/1477760620977500 ◽

2020 ◽

pp. 147776062097750

Author(s):

Moein Khoshroo ◽

Ali Akbar Shirzadi Javid ◽

Nima Rajabi Bakhshandeh ◽

Mohamad Shalchiyan

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Compressive Strength ◽

Polypropylene Fiber ◽

Crumb Rubber ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Fine Aggregate ◽

Mixture Ratio ◽

Coarse Aggregates

In this study, the effect of using crumb rubber and recycled aggregates on the mechanical properties of concrete has been evaluated as areplacement of fine and coarse aggregates In order to add the admixtures and evaluate their combined effect, 20 different types of concrete mixture ratio were prepared. The results indicated that in those samples containing crumb rubber and recycled aggregates the compressive strength is reduced and adding fiber up to 0.1%. to these concrete samples can improve the compressive strength Also, the tensile strength of the samples mixed with crumb rubber and recycled aggregates were decreased, and with the addition of propylene fiber up to 0.4%. the tensile strength slightly increased Moreover by adding the crumb rubber to the samples the elasticity modulus was reduced but by adding fiber to samples about 0.1% and 0.2.% the modulus of elasticity of concrete in all samples were increased. According to the results, it can be said that using the combination of 5% of crumb rubber as a replacement of fine aggregate, and the combination of 35% of recycled aggregates as a replacement of coarse aggregate, and also by adding 0.1% polypropylene fiber in volumetric percentage of concrete along with adding 7% of micro silica as a replacement of cement led to the best effect on the mechanical properties of concrete.

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Application and Development of Materials for ‘Green’ Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.848.135 ◽

2013 ◽

Vol 848 ◽

pp. 135-138

Author(s):

Jia Zi Shi ◽

Xing Dang

Keyword(s):

Environmental Impact ◽

Construction Material ◽

Recycled Aggregates ◽

Mineral Admixtures ◽

Environmental Damage ◽

New Materials ◽

Green Concrete ◽

The Past ◽

Concrete Production ◽

The World

Concrete is the most commonly used construction material in the world over the past decades. But the increase in concrete production leads to an increase in greenhouse gases emission and environmental damage. With the current focus on sustainability, it is necessary to evaluate concretes environmental impact and develop new materials for green concrete. Green recycled aggregates and mineral admixtures are important component materials for green concrete. In this paper, the development of green concrete industry is introduced, and the application of materials for green concrete such as green recycled aggregates and mineral admixtures are discussed.

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