Current progress on nanotechnology application in recycled aggregate concrete

Luo, Zhibing; Li, Wengui; Tam, Vivian W.Y.; Xiao, Jianzhuang; Shah, Surendra P.

doi:10.1080/21650373.2018.1519644

Cited by 48 publications

(12 citation statements)

References 60 publications

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“…The building industries extract about 7.5 billion tonnes of natural aggregates annually from the earth, which has significant adverse effects on the environment. The overexploitation of natural resources and environmental degradation can be unravelled by the substitution of natural aggregates with RCA in civil and construction engineering [15][16][17][18][19][20][21][22][23]. On the other hand, the mechanical properties of recycled aggregate concrete are lower than those of the normal aggregate concrete due to the weaker bonds of adhered old mortar to RCA with cement particles, leading to decreasing the compressive strength of recycled aggregate concrete as reported by Assaad et al [24].…”

Section: Introductionmentioning

confidence: 99%

In-situ strength estimation of polypropylene fibre reinforced recycled aggregate concrete using Schmidt rebound hammer and point load test

Kazemi

Hajforoush

Talebi

et al. 2020

Journal of Sustainable Cement-Based Materials

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An appropriate amount of polypropylene fibre (PF) content is generally able to compensate for the low compressive strength of the recycled aggregate concrete. This mechanical strength is required to reliably estimate at the building site using partially and non-destructive testing methods. Therefore, in the present study, the compressive strength of concrete with PF at 0.1% by volume and different replacement levels of recycled coarse aggregate (RCA) was assessed using point load test (PLT) and Schmidt rebound hammer. According to the results, the sensitivity of the core specimens to the concentrated point load and the short size of PF in the failure zone of the PLT caused to appear a difference among the enhancement trends of PLI values by increasing the age. In addition, a two-variable equation between the rebound number and point load index (PLI) reliably predicted either strength of coarse natural concrete or recycled aggregate concrete or PRAC.

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Section: Introductionmentioning

confidence: 99%

In-situ strength estimation of polypropylene fibre reinforced recycled aggregate concrete using Schmidt rebound hammer and point load test

Kazemi

Hajforoush

Talebi

et al. 2020

Journal of Sustainable Cement-Based Materials

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“…Generally, the mechanical performances of RAC are slightly inferior to those of the natural aggregate concrete (NAC) given the same mix proportion. The reduction of the mechanical properties is related to the weak interfacial transition zones (ITZs) that existed in RAC due to the adhered mortar with porous nature attached to RCAs (Duan and Poon, 2014; Lee and Choi, 2013; Luo et al, 2018; McNeil and Kang, 2013; Otsuki et al, 2003; Sáez del Bosque et al, 2017; Sahu et al, 2016). In addition to their mix proportions, the properties of RAC also depend on the physical (i.e.…”

Section: Introductionmentioning

confidence: 99%

A review of experimental results on structural performance of reinforced recycled aggregate concrete beams and columns

Deresa

Demartino

et al. 2020

Advances in Structural Engineering

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This article presents a comprehensive and critical review of the structural performances of reinforced recycled aggregate concrete beams and columns based on experimental results reported in the literature. Extensive data sets collected from the literature are categorized to investigate the effects on the local and global structural behavior. First, the flexural and shear response of reinforced recycled aggregate concrete beams is discussed. The structural performances are reviewed focusing on the main geometric and material variables such as the recycled concrete aggregate replacement ratio, the longitudinal reinforcement ratio, the transverse reinforcement ratio, and the shear span-to-depth ratio. Then, the behavior of reinforced recycled aggregate concrete columns under concentric and eccentric compressive loads and the seismic performance under low cyclic loading are discussed. The similarities and the differences between reinforced recycled aggregate concrete and reinforced natural aggregate concrete beams and columns are highlighted. The need for further research is pointed out at the end of the article. The results reported in this review clearly indicate that reinforced recycled aggregate concrete beams and columns with various recycled concrete aggregate replacement ratios have comparable or slightly lower structural performances to the reinforced natural aggregate concrete ones indicating the feasibility of recycled concrete aggregate for structural applications.

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“…In the former, the rapid heating of the outer layer results in thermal gradients that cause up to 50% of the attached mortar to be spalled out, whereas through the latter, accelerated RA particles (up to 100 m/ s) strike each other, causing the removal of up to 90% of the attached mortar after a few treatment cycles. Techniques to improve the quality of the adhered mortar have also been validated and include pre-soaking of the aggregates in suspensions consisting of cement slurry (proven effective in improving the freeze-thaw resistance), polymer or sodium silicate solutions deemed to increase the density, and also slurries of fly ash, metakaolin, silica fume, ground granulated blast furnace slag, and nano-silica (Luo et al, 2019). Carbonation of RAs has been also investigated as a means to improve the quality of the adhered mortar, through the deposition of the carbonation products in the pores (Ma et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Performance Assessment of Ultra-High Durability Concrete Produced From Recycled Ultra-High Durability Concrete

Borg

Cuenca

Garofalo

et al. 2021

Front. Built Environ.

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The purpose of the work reported in this paper is to assess the performance of recycled ultra-high durability concrete (R-UHDC), produced using different fractions of recycled aggregate obtained from crushed ultra-high durability concrete (UHDC), as a substitute for the natural aggregate. Four different recycled ultra-high durability concrete (R-UHDC) mixes were designed and manufactured with a reference mix based on the natural aggregate and three mixes with the natural aggregate replaced using recycled UHDC according to two percentage replacement values (50 and 100%). The effect of environmental degradation of the recycled parent concrete was also addressed, using recycled aggregates subjected to accelerated carbonation (replacement percentage equal to 50%). The work has been conducted in the framework of the activities of the Horizon 2020 ReSHEALience Project in ultra-high durability concrete. One key objective of the project was to formulate the concept and experimentally validate the performance of ultra-high durability concrete for structures and infrastructures exposed to extremely aggressive scenarios. The ReSHEALience consortium has defined UHDC as a “strain-hardening (fiber-reinforced) cementitious material with functionalizing micro- and nano-scale constituents especially added to deliver high durability in the cracked state under extremely aggressive exposure conditions.” In this context, the research was conducted to investigate the potential of recycling the UHDC mixes, developed and validated in previous research and employing them as a partial or even total replacement of the natural fine aggregate in the production of new UHDC. This supports the cradle-to-cradle approach in life cycle engineering applications. The research confirmed the effective regeneration of new UHDC based on the recycled aggregate obtained from crushed UHDC, attaining the required rheological characteristics, mechanical properties (compressive strength, flexural strength, and toughness), and durability performance (chloride penetration resistance, chloride migration, water capillary suction, and resistivity). This work is intended as the first step toward the sustainability assessment of the end of life of UHDC materials and structures and the potential of recycled UHDC for new structures and retrofit structural applications.

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Current progress on nanotechnology application in recycled aggregate concrete

Cited by 48 publications

References 60 publications

In-situ strength estimation of polypropylene fibre reinforced recycled aggregate concrete using Schmidt rebound hammer and point load test

In-situ strength estimation of polypropylene fibre reinforced recycled aggregate concrete using Schmidt rebound hammer and point load test

A review of experimental results on structural performance of reinforced recycled aggregate concrete beams and columns

Performance Assessment of Ultra-High Durability Concrete Produced From Recycled Ultra-High Durability Concrete

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