Advances in Recycled Aggregate Concrete

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Inorganic Crystalline Materials".

Deadline for manuscript submissions: closed (31 August 2022) | Viewed by 16122

Special Issue Editors

School of Science, Engineering & Environment, University of Salford, Manchester M54WT, UK
Interests: Green construction materials; Structural durability; Water Environment; Sustainable development

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Guest Editor
Department of Civil Engineering, University of Baghdad, Baghdad 10071, Iraq
Interests: Civil engineering materials; Structural engineering

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Co-Guest Editor
School of Civil Engineering & Architecture, NingboTech University, Ningbo 315100, China
Interests: civil engineering materials; building materials; construction materials; concrete technologies; concrete durability; concrete material technology; cement; concrete; nondestructive testing; silicate cement; chlorides

Special Issue Information

Dear Colleague,

The construction industry produces about 1183 million metric tons of construction and demolition wastes each year worldwide, in which concrete waste takes the most considerable proportion. The disposal of such huge quantities of waste has become an enormous burden to landfill capacity and environment. Recycling this waste and using it in new construction has been regarded as a viable solution for the sake of sustainable development.

However, as a substitute resource for virgin raw materials, deep knowledge of how the use of recycled aggregates influences the final concrete properties is still very limited, particularly considering that the recycled aggregates have wide uncertainty and variability in quality. How do their inherited faults in microstructure and purity influence the hydration process and bond with paste matrix? How do advanced improving technologies work in scientific mechanisms, etc.? To promote communication of the knowledge and research in material science on the topic, we have planned this Special Issue and are inviting worldwide researchers to contribute their original research work, case investigations, reviews of research development, and advances in the research area.


Dr. Yu Wang
Prof. Dr. Amjad Albayati
Prof. Dr. Jian Geng
Guest Editors

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Keywords

  • Microstructure of recycled aggregates
  • Characterization of microscopic quality
  • Microscopic analysis and technology application on recycled aggregated concrete
  • Hydration mechanism using recycled aggregates
  • Bonding at the interface of recycled aggregates
  • Microscopic failure mechanism of recycled aggregated concrete
  • Improving technologies and their material scientific mechanisms

Published Papers (7 papers)

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Research

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13 pages, 915 KiB  
Article
Structure Strength Correction Value for Concrete’s Mix Proportion Strength Using Low-Quality Recycled Aggregate
by Yasuhiro Dosho
Crystals 2022, 12(4), 488; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst12040488 - 01 Apr 2022
Cited by 1 | Viewed by 1759
Abstract
To develop a design method for concrete using low-quality recycled aggregates, an experimental study was conducted on applicability to examine the structural strength correction value (S value) and calculation of mix proportion strength of recycled aggregate concrete-Class M, which used recycled aggregate class [...] Read more.
To develop a design method for concrete using low-quality recycled aggregates, an experimental study was conducted on applicability to examine the structural strength correction value (S value) and calculation of mix proportion strength of recycled aggregate concrete-Class M, which used recycled aggregate class L mixing with the normal aggregate. Cement used in the experiment was ordinary Portland cement (in this case, fly ash type II was used as a fine aggregate substitute), Portland blast-furnace slag cement type B, and low-heat Portland cement. As a result, the mix proportion strength of recycled aggregate concrete-Class M could be determined using the S value according to JASS 5 (2018) as normal-weight concrete. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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19 pages, 5215 KiB  
Article
Effects of a Water-Glass Module on Compressive Strength, Size Effect and Stress–Strain Behavior of Geopolymer Recycled Aggregate Concrete
by Qing Wang, Hongguang Bian, Mingze Li, Min Dai, Yanwen Chen, Hongwei Jiang, Qiang Zhang, Fengxin Dong, Jian Huang and Zhaoyang Ding
Crystals 2022, 12(2), 218; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst12020218 - 01 Feb 2022
Cited by 10 | Viewed by 2029
Abstract
Geopolymer recycled aggregate concrete (GRAC) was prepared by replacing cement with geopolymer and natural aggregate with waste concrete. The effect of the water-glass module on the mechanical properties of GRAC was studied. It was found that water-glass has a double-layer structure. The low [...] Read more.
Geopolymer recycled aggregate concrete (GRAC) was prepared by replacing cement with geopolymer and natural aggregate with waste concrete. The effect of the water-glass module on the mechanical properties of GRAC was studied. It was found that water-glass has a double-layer structure. The low module water-glass leads to a thicker diffusion layer and more Na+ and OH in the solution, which activates more CaO, SiO2, and Al2O3 in the raw material, and improves the strength of GRAC. Moreover, two kinds of gel structures, namely layered C-A-S-H (calcium silicate hydrate) and networked N-A-S-H (zeolite), were found in the products of geopolymer. As the water-glass module changed, the phase of zeolite changed significantly, whereas the calcium silicate hydrate did not change, indicating that the decrease in the water-glass module contributes to the formation of more N-A-S-H gel. The compressive strengths of GRAC with the sizes of 200, 150, and 100 mm3 were in line with Bazant’s size effect theoretical curve. Through the segmented fitting method, the relationship of the size conversion coefficient of GRAC (α), the critical strength (fcr), the critical dimension (Dcr), and the water-glass module (ε) were determined. It was found that ε = 1.5 is the segmented point of the three equations. The elastic modulus and peak stress of GRAC are inversely proportional to the water-glass module, and the peak strain is proportional to the water-glass module, indicating that by reducing the water-glass module, the strength of GRAC can be improved, but the brittleness is increased. The constitutive equation of GRAC with only the water-glass module as a variable was also established. It was found that the polynomial mathematical model and rational fraction mathematical model are optimal for the rising-stage and falling-stage, respectively, and the relationship between the parameters of the rising-stage (a) and the falling-stage (b), and the water-glass module, is given. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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17 pages, 8343 KiB  
Article
Bond Behavior of Recycled Fiber Recycled Concrete with Reinforcement after Freeze-Thaw Cycles
by Yu Liu, Jinghai Zhou, Di Wu, Tianbei Kang and Aixia Liu
Crystals 2021, 11(12), 1506; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst11121506 - 03 Dec 2021
Cited by 5 | Viewed by 1536
Abstract
Freeze-thaw (F-T) damage is the major factor destroying the bond behavior of reinforced concrete in the cold areas of China. The bond behavior between recycled fiber recycled concrete (RFRC) and reinforcement after F-T cycles was investigated in this paper. The pull-out tests were [...] Read more.
Freeze-thaw (F-T) damage is the major factor destroying the bond behavior of reinforced concrete in the cold areas of China. The bond behavior between recycled fiber recycled concrete (RFRC) and reinforcement after F-T cycles was investigated in this paper. The pull-out tests were undertaken with the replacement rate (0, 50%, and 100%) of recycled aggregates (RA) and volume content (0, 0.12%, and 0.24%) of recycled fibers (RFs) as test variables. The results demonstrate that the F-T cycles will reduce the bond strength between RFRC and reinforcement. Bond strength decreases by 69.41% after 150 cycles. Moreover, RF can improve the bond strength between RFRC and reinforcing steel. Bonding strength increases by 11.35% with the addition of 0.12% RF. A simplified two-phase bond-slip model between RFRC and reinforced steel after F-T cycles was eventually established, and it correlated well with the experimental results. This research presents a theoretical basis for the application of RFRC in building structures in cold areas. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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10 pages, 1984 KiB  
Article
Phases Reconstruction and Foaming Modification of Basic Oxygen Furnace Slag on Its Grindability
by Ruiheng Xiang, Ping Chen, Rongjin Liu, Cheng Hu, Dandan Wan, Jintao Fan and Jiazhan Wei
Crystals 2021, 11(9), 1051; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst11091051 - 01 Sep 2021
Cited by 3 | Viewed by 2319
Abstract
Basic oxygen furnace (BOF) slag is a main byproduct produced during the converter steelmaking process. The poor grindability of BOF slag limits its added-value application. In this paper, the grinding characteristics of unmodified and reconstructed BOF slag were compared. Additionally, the grinding property [...] Read more.
Basic oxygen furnace (BOF) slag is a main byproduct produced during the converter steelmaking process. The poor grindability of BOF slag limits its added-value application. In this paper, the grinding characteristics of unmodified and reconstructed BOF slag were compared. Additionally, the grinding property of reconstructed steel slag was also studied after SiC foaming. The results show that the solid solution of divalent metal oxides’ RO phase, considered as the hardly grinding phase, discomposes after lime-bauxite reconstruction. The characteristics of BOF slag were tested through particle size analysis, XRD, SEM and MIP. The SSA (specific suface area) and the particle diameter of unmodified BOF slag could reach 303.1 m2/kg and 51.75 µm after 10 min of grinding, but that of reconstructed BOF slag could reach 354.5 m2/kg and 18.16 µm after the same grinding time, respectively. The grinding efficiency of steel slag was obviously increased and the particle characteristics were improved after foaming modification. BOF formed as a porous structure after SiC foaming; its porosity, SSA, and particle diameter can reach 31.79%, 424.4 m2/kg, and 24.36 μm and increased by 10.31%, 19.72%, and 39.04%, compared with the reconstructed steel slag of undoped foaming agent, respectively, and the grindability was further improved. A theoretical basis for large-scale BOF slag utilization is provided. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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14 pages, 3721 KiB  
Article
Study on the Performance of Synergistic Preparation of Sulphoaluminate Based Recycled Concrete by RP and RCA
by Zhenwen Hu, Qiuyi Li, Yuanxin Guo, Xiangling Lin, Junzhe Liu and Shidong Zheng
Crystals 2021, 11(7), 748; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst11070748 - 26 Jun 2021
Viewed by 1405
Abstract
In this paper, the properties of sulphoaluminate based recycled concrete, with high workability and low and medium strength, prepared by recycled powder (RP), recycled coarse aggregate (RCA), and high belite sulphoaluminate cement (HBSAC), were systematically studied. Under the condition of a water binder [...] Read more.
In this paper, the properties of sulphoaluminate based recycled concrete, with high workability and low and medium strength, prepared by recycled powder (RP), recycled coarse aggregate (RCA), and high belite sulphoaluminate cement (HBSAC), were systematically studied. Under the condition of a water binder ratio of 0.45, sulphoaluminate based recycled concrete, with different mix proportions, was prepared by replacing sulphoaluminate cement with RP and natural coarse aggregate (NCA) with RCA. The workability, mechanical properties, durability, and hydration products of the prepared concrete were analyzed. The results showed that when RP and RCA were used together, the workability of recycled concrete could fully meet the pumping demand in actual construction. When the mass replacement rate of RP was less than 30% and that of RCA was less than 20%, the strength of recycled concrete could completely reach the design strength grade, while those that did not reach the design strength grade could reach the next grade. The durability performance was also good. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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23 pages, 1783 KiB  
Article
Effect of Mineral Admixtures on the Performance of Low-Quality Recycled Aggregate Concrete
by Yasuhiro Dosho
Crystals 2021, 11(6), 596; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst11060596 - 25 May 2021
Cited by 4 | Viewed by 2915
Abstract
To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could [...] Read more.
To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could be improved by varying the replacement ratio of the recycled aggregate and using appropriate mineral admixtures such as fly ash and ground granulated blast-furnace slag. The results show the potential for the use of low-quality aggregate in structural concrete. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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Review

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22 pages, 4068 KiB  
Review
Review of the Strengthening Methods and Mechanical Properties of Recycled Aggregate Concrete (RAC)
by Chuanqi Liu, Yanjun Wang, Xuyang Gao, Guanglong Zhang, Heng Liu, Chong Ma, Jilin Sun and Jinxing Lai
Crystals 2022, 12(9), 1321; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst12091321 - 19 Sep 2022
Cited by 3 | Viewed by 2431
Abstract
Replacing natural aggregate (NA) with recycled aggregate (RA) has contributed to the trend of sustainable development in civil construction. With this background, improvements in the mechanical properties of recycled aggregate concrete (RAC) and the scientific design of the mixture ratio are attracting more [...] Read more.
Replacing natural aggregate (NA) with recycled aggregate (RA) has contributed to the trend of sustainable development in civil construction. With this background, improvements in the mechanical properties of recycled aggregate concrete (RAC) and the scientific design of the mixture ratio are attracting more concern in recent years. This paper is a review of the recent research, including the following aspects: the mixture design of RAC; the improved mechanical properties of recycled concrete with steel fibers; and the performance of the main components. In addition, the primary composition materials, properties, and calculation methods of the mixture ratio of RAC are summarized. The mechanical properties, durability and microscopic analysis of RAC are also discussed. The accurate calculation of mixture proportion can significantly facilitate the work of preparing a test mix of RAC. Through the mixture-ratio optimization and physical and chemical strengthening of RA, the mechanical properties of RAC can be improved to promote the wider application of this eco-friendly material. Full article
(This article belongs to the Special Issue Advances in Recycled Aggregate Concrete)
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