Enhancement Treatment of Recycled Concrete Aggregate

Chen, Kehan; Zhu, Zhiying; Xue, Tao; Zhang, Heng; Wang, Anyang; He, Rui; Yang, Hao; Wang, Yufei

doi:10.3389/fbuil.2021.739148

Cited by 4 publications

(2 citation statements)

References 10 publications

(9 reference statements)

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“…The quality of RA depends on the treatment method and degree of the aggregates. Common treatment methods include mechanical [18], chemical [19,20], and biological [21,22] treatments. The purpose of these treatments is to remove or enhance the old mortar attached to the surface of the RA, thereby enhancing its quality.…”

Section: Introductionmentioning

confidence: 99%

Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete: A Review

Zhang¹,

Wang²,

Zheng³

et al. 2023

Journal of Renewable Materials

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Using recycled aggregate (RA) and slag instead of natural aggregate (NA) and cement can reduce greenhouse gas emissions (GHGE) and achieve effective waste recovery. In recent years, RA has been widely used to replace NA in concrete. Every year, several researchers conduct investigations on the mechanical performance and durability of recycled aggregate concrete (RAC). Due to the loose and porous material properties of RA, the mechanical properties and durability of RAC, such as strength, carbonation resistance, permeability resistance and chloride ion penetration resistance, are greatly reduced compared with natural aggregate concrete. In contrast, concrete containing slag instead of NA and cement generally improved the strength of concrete and reduced the internal porosity of materials. Herein, we discuss the effects of RA and slag on the workability, compressive strength, splitting tensile strength, ultrasonic pulse velocity (UPV) value, and elastic modulus of concrete. The relationships between the compressive strength and the splitting tensile strength, UPV value, and elastic modulus are discussed, and the optimal substitution method is proposed. In addition, various equations for calculating the compressive strength of concrete based on performance factors related to the compressive strength are summarized.

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Section: Introductionmentioning

confidence: 99%

Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete: A Review

Zhang¹,

Wang²,

Zheng³

et al. 2023

Journal of Renewable Materials

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“…However, coarse RCA is characterized by more than one ITZ in RCA [11,37]. is area was found to be highly porous and mainly composed of a high amount of calcium hydroxide (C-H), other hydration products (calcium hydrate, ettringite), and unhydrated cement grains [38]. Li et al and Liang et al [39,40], while focusing on the interface bond between the new concrete mortar and the surface of RCA, recommended surface pretreatment, i.e., coating RCA with cement slurry plus silica solution, and found positive results with the compressive strength of concrete.…”

Section: Introductionmentioning

confidence: 99%

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

Odero¹,

Mutuku

Nyomboi³

et al. 2022

Advances in Materials Science and Engineering

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e use of concrete mixes with recycled materials has gained traction in research communities. However, the major drawback of the recycled concrete aggregate (RCA) has been the contribution of the cement paste mortar attached to the surface. e quantity of surface-attached mortar on the virgin aggregate dominates and de nes the shear performance of concrete beams. Concrete shear failure is usually abrupt and catastrophic, especially in concrete beams without shear reinforcement. e e ectiveness of the maximum size of RCA for the performance of untreated and treated with pozzolanic cement and rice husk ash (RHA) slurry was investigated. A total of sixteen ( 16) beams containing RCA of four (4) maximum sizes, 10, 14, 20, and 25 mm, were prepared and tested after 28 days. e beams were loaded in shear using shear span-depth ratios of 1.25 and 2.50. e results showed that the shear strength of the beams increases as the aggregate size increases to a maximum size of 20 mm, beyond which the shear strength reduces. It was attributed to the attached mortar, which increased as the size of the aggregate increased, creating a weak zone for shear failure in the concrete. In addition, RCA pretreatment using slurry-containing cement and RHA strengthened the attached mortar on the aggregate surface. It resulted in a dense and more compact aggregate that slightly improved the shear strength by about 2.2% for beams containing 20 mm RCA size. e ultimate shear strength of the experimental work in the study was predicted using eight (8) selected models from the literature. Models that account for the aggregate size and shear span to depth ratio resulted in shear strength ratios of 1.

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CO2 treatment of recycled concrete aggregates with high mortar contents: From finding optimal treatment condition, quality enhancement, to life cycle assessment

Jeon,

Kim,

Ham

et al. 2024

Construction and Building Materials

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Enhancement Treatment of Recycled Concrete Aggregate

Cited by 4 publications

References 10 publications

Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete: A Review

Effect of Recycled Aggregate and Slag as Substitutes for Natural Aggregate and Cement on the Properties of Concrete: A Review

Shear Performance of Concrete Beams with a Maximum Size of Recycled Concrete Aggregate

CO2 treatment of recycled concrete aggregates with high mortar contents: From finding optimal treatment condition, quality enhancement, to life cycle assessment

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