Long-term shrinkage and mechanical properties of fully recycled aggregate concrete: Testing and modelling

Zhang, Hanghua; Xiao, Jianzhuang; Tang, Yuxiang; Duan, Zhenhua; Poon, Chi-Sun

doi:10.1016/j.cemconcomp.2022.104527

Cited by 103 publications

(19 citation statements)

References 45 publications

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“…Compared with blending into dry recycled coarse aggregate, the strength improvement of RAC can reach up to 9.4% at 60 d after pre-wetting of recycled coarse aggregate. This shows that the effect of pre-wetted recycled coarse aggregate internal curing on the compressive strength of concrete starts to manifest after 28 d. As shown in Figure 9 it is difficult for cement to obtain water from outside due to the dense structure of concrete with low W/B in the later stages [ 23 , 24 ]. As curing continues, the relative humidity inside the concrete decreases as pre-wetted recycled coarse aggregate transfers water through capillary pores.…”

Section: Resultsmentioning

confidence: 99%

Study on the Mechanical Properties and Durability of Recycled Aggregate Concrete under the Internal Curing Condition

Yang

Guo

et al. 2022

Materials

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Poor mechanical properties and durability of recycled aggregate concrete (RAC) hinder its application in the construction field. In this study, pre-wetted recycled coarse aggregate was used as the internal curing material for prepared RAC with low water-to-binder ratio (W/B), aiming to improve the mechanical properties and durability. The results show that the workability decreases with increasing contents of pre-wetted recycled coarse aggregate. The variation in compressive strength of RAC with different contents of pre-wetted recycled coarse aggregate is obvious within 28 d. After 28 d, the effect of internal curing of pre-wetted recycled coarse aggregate starts to occur, causing a sustained increase in compressive strength. The sealed concrete with 50% and 75% pre-wetted recycled coarse aggregate contents presents the highest compressive strength and better internal curing effect. The pre-wetted recycled coarse aggregate decreases the relative humidity inside the concrete and effectively inhibits the development of shrinkage in the early stages. The RAC with pre-wetted recycled coarse aggregate presents little effect on the drying shrinkage. Additionally, the electric flux of RAC cured for 28 d increases from 561C to 1001C, which presents good resistance to chloride permeation. Microscopic tests indicate that the incorporation of pre-wetted recycled coarse aggregate is beneficial to the improvements of internal structure of RAC.

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Section: Resultsmentioning

confidence: 99%

Study on the Mechanical Properties and Durability of Recycled Aggregate Concrete under the Internal Curing Condition

Yang

Guo

et al. 2022

Materials

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“…The current over-exploitation of NA has caused a shortage of natural sand and gravel resources in some areas, and has also caused damage to the ecological environment. Moreover, the unreasonable disposal of large amount of construction waste has caused certain environmental problems [ 21 ]. Therefore, green concrete needs to be prepared to solve these problems.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Durability of Geopolymer Recycled Aggregate Concrete: A Review

et al. 2023

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Geopolymer recycled aggregate concrete (GPRAC) is a new type of green material with broad application prospects by replacing ordinary Portland cement with geopolymer and natural aggregates with recycled aggregates. This paper summarizes the research about the mechanical properties, durability, and microscopic aspects of GPRAC. The reviewed contents include compressive strength, elastic modulus, flexural strength, splitting tensile strength, freeze–thaw resistance, abrasion resistance, sulfate corrosion resistance, and chloride penetration resistance. It is found that GPRAC can be made to work better by changing the curing temperature, using different precursor materials, adding fibers and nanoparticles, and setting optimal mix ratios. Among them, using multiple precursor materials in synergy tended to show better performance compared to a single precursor material. In addition, using modified recycled aggregates, the porosity and water absorption decreased by 18.97% and 25.33%, respectively, and the apparent density was similar to that of natural aggregates. The current results show that the performance of GPRAC can meet engineering requirements. In addition, compared with traditional concrete, the use of GPRAC can effectively reduce carbon emissions, energy loss, and environmental pollution, which is in line with the concept of green and low-carbon development in modern society. In general, GPRAC has good prospects and development space. This paper reviews the effects of factors such as recycled aggregate admixture and curing temperature on the performance of GPRAC, which helps to optimize the ratio design and curing conditions, as well as provide guidance for the application of recycled aggregate in geopolymer concrete, and also supply theoretical support for the subsequent application of GPRAC in practical engineering.

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“…By the year 2100, the amount of sand used is projected to reach 25 billion tons annually, significantly exceeding the available supply of approximately 10 billion tons per year [5]. With the growing demand for natural materials, these resources are becoming increasingly scarce, directly impacting aggregates' rising prices and, consequently, the cost per cubic meter of concrete [6][7][8].…”

Section: Introduction 1overviewmentioning

confidence: 99%

A Comprehensive Review of Stone Dust in Concrete: Mechanical Behavior, Durability, and Environmental Performance

et al. 2023

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The escalating demand for natural resources within the construction industry is progressing upward. At the same time, however, there is a great concern regarding the depletion of these resources. This review paper emphasizes the significance of utilizing alternative aggregate materials in concrete. Particularly, it aims to explore replacing natural sand with stone dust. On the one hand, the depletion of primary sources of natural sand worldwide, combined with environmental and ecological concerns, drives the adoption of alternative aggregate materials for sustainable concrete construction. On the other hand, stone dust, a waste from the quarrying industry, offers a cost-effective and practical solution for producing concrete. This article presents a comprehensive literature review of the main trends in utilizing stone dust in recycled aggregates in the past decade and its influence on concrete properties. It addresses critical research questions regarding the physical and chemical properties of stone dust aggregates compared to natural sand; the impact of stone dust on the workability, mechanical, physical, and durability properties of recycled concrete; and the potential reduction of environmental impacts in terms of energy consumption and emissions through the replacement of natural sand with stone dust. Ultimately, this paper proposes future investigative work based on identified research gaps.

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Long-term shrinkage and mechanical properties of fully recycled aggregate concrete: Testing and modelling

Cited by 103 publications

References 45 publications

Study on the Mechanical Properties and Durability of Recycled Aggregate Concrete under the Internal Curing Condition

Study on the Mechanical Properties and Durability of Recycled Aggregate Concrete under the Internal Curing Condition

Mechanical Properties and Durability of Geopolymer Recycled Aggregate Concrete: A Review

A Comprehensive Review of Stone Dust in Concrete: Mechanical Behavior, Durability, and Environmental Performance

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