Improved freeze-thaw modification of recycled concrete aggregate originally from frost resistive concrete

Xia, Peng; Yang, Liu; Wang, Shiqi; Gong, Fuyuan; Cao, Wanlin; Zhao, Yuxi

doi:10.1016/j.cemconcomp.2023.105302

Cited by 17 publications

(2 citation statements)

References 55 publications

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“…This is mainly because the water storage function of zeolite powder can promote the secondary hydration of cement and the pozzolanic reaction, producing hydration products that can fill the ITZ between recycled aggregates and mortar [ 36 , 49 ]. Additionally, the particle-filling and water storage functions of zeolite powder also reduce the free water content inside ZPRC, thereby reducing the damage of ice crystal expansion to the microstructure [ 50 , 51 ]. This is also consistent with the results of the ZPRC water absorption test described above.…”

Section: Resultsmentioning

confidence: 99%

Freeze–Thaw Cycle Durability and Mechanism Analysis of Zeolite Powder-Modified Recycled Concrete

Yu,

Zhang,

Cao

et al. 2024

Materials

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The inferior mechanical performance and freeze–thaw (FT) resistance of recycled concrete are mostly due to the significant water absorption and porosity of recycled coarse particles. In this study, different dosages of zeolite powder were used in recycled concrete. A series of macroscopic tests were used to evaluate the workability and FT durability of zeolite powder-modified recycled concrete (ZPRC). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to reveal the micro-mechanisms of FT resistance in ZPRC. The results show that the increase in zeolite powder content leads to a decrease in the slump and water absorption of ZPRC. Additionally, ZPRC with 10% zeolite powder has superior mechanical characteristics and tolerance to FT conditions. The higher strength and FT resistance of the ZPRC can be attributed to the particle-filling effect, water storage function, and pozzolanic reaction of zeolite powder, which results in a denser microstructure. The particle-filling effect of zeolite powder promotes the reduction of surface pores in recycled coarse aggregates (RCAs). The water storage function of zeolite powder can provide water for the secondary hydration of cement particles while reducing the free water content in ZPRC. The pozzolanic reaction of zeolite powder can also promote the generation of hydrated calcium silicate and anorthite, thereby making the microstructure of ZPRC more compact. These results provide theoretical guidance for the engineering application of recycled concrete in cold regions.

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Section: Resultsmentioning

confidence: 99%

Freeze–Thaw Cycle Durability and Mechanism Analysis of Zeolite Powder-Modified Recycled Concrete

Yu,

Zhang,

Cao

et al. 2024

Materials

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“…The porous characteristics of aggregates contribute to delaying freeze-thaw damage in concrete. Xia et al [52] proposed that porous aggregates can accommodate more pore water, thereby enhancing the freeze resistance of concrete. Using numerical simulations, Gong et al [53] investigated freeze-thaw damage.…”

Section: Freeze-thaw Cyclingmentioning

confidence: 99%

Investigation of Mechanical Properties of Ultra-High-Performance Polyethylene-Fiber-Reinforced Recycled-Brick-Aggregate Concrete

Ji,

Pei

2023

Polymers

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The utilization of ultra-high-molecular-weight polyethylene fibers (UHMWPEFs) to enhance recycled-brick-aggregate concrete represents an efficacious approach for ameliorating the concrete’s performance. This investigation addresses the influences of recycled-brick aggregates (RAs) and UHMWPEFs on the concrete’s slump, shrinkage, flexural strength, resistance to chloride-ion ingress, and freeze–thaw durability. The mechanisms through which UHMWPEFs ameliorate the performance of the recycled-brick-aggregate concrete were elucidated at both the micro and macroscopic levels. The findings underscore that the three-dimensional network structure established by the UHMWPEFs, while resulting in a reduction in the concrete slump, substantially enhances the concrete’s mechanical properties and durability. A regression model for the multifaceted performance of the UHMWPEF-reinforced recycled-brick-aggregate concrete (F-RAC) was formulated by employing response-surface methodology, and the model’s reliability was confirmed through variance analysis. The interactive effects of the RA and UHMWPEFs on the concrete were analyzed through a combined approach involving response-surface analysis and contour plots. Subsequently, a multiobjective optimization was conducted for the F-RAC performance, yielding the optimal proportions of RA and UHMWPEFs. It was determined that the optimal performance across the dimensions of the shrinkage resistance, flexural strength, chloride-ion resistance, and freeze–thaw durability of the F-RAC could be simultaneously achieved when the substitution rate of the RA was 14.02% and the admixture of the UHMWPEFs was 1.13%.

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RBSM-based mesoscale study of mechanical properties and frost damage behaviors for recycled fine aggregate concrete

Zhi,

Xia,

Wang

et al. 2024

Construction and Building Materials

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Improved freeze-thaw modification of recycled concrete aggregate originally from frost resistive concrete

Cited by 17 publications

References 55 publications

Freeze–Thaw Cycle Durability and Mechanism Analysis of Zeolite Powder-Modified Recycled Concrete

Freeze–Thaw Cycle Durability and Mechanism Analysis of Zeolite Powder-Modified Recycled Concrete

Investigation of Mechanical Properties of Ultra-High-Performance Polyethylene-Fiber-Reinforced Recycled-Brick-Aggregate Concrete

RBSM-based mesoscale study of mechanical properties and frost damage behaviors for recycled fine aggregate concrete

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