Mechanical and durability properties of concrete based on recycled coarse and fine aggregates produced from demolished concrete

Berredjem, Layachi; Arabi, Nourredine; Molez, Laurent

doi:10.1016/j.conbuildmat.2020.118421

Cited by 108 publications

(54 citation statements)

References 32 publications

(47 reference statements)

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“…These results are related to the fines of the crushed sand, which helped reduce the porosity of the concrete. This result is in agreement with the work of Layachi et al [26]. Figure 9 (the water accessible porosity of concrete).…”

Section: Gas Permeabilitysupporting

confidence: 93%

Microstructure and Mechanical Behavior of Concrete Based on Crushed Sand Combined with Alluvial Sand

et al. 2020

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The aim of this work is to reduce the overexploitation of river sand by proposing a combination of crushed sand and river sand to develop an optimal mix design for concrete. The approach used consisted of a physical, chemical, and mineralogical characterization of aggregates from three quarries located in Yaoundé (Cameroon), followed by the formulation of concrete by substituting 100%, 90%, 80%, 70%, 50%, and 0% of the river sand with crushed sand. A physical and mechanical characterization of the concrete was carried out, as well as a microstructural characterization using SEM/EDS. The results showed that the concrete made of crushed sand only had a higher drying shrinkage at a young age compared to the river sand concrete. Compared to conventional concrete (made using 100% of river sand), the concrete with 50% crushed sand reduces its slump value, has a lower porosity, and has a compressive strength value of 26.3 MPa at 28 days, which is very similar to that of conventional concrete (26.7 MPa). Moreover, it was found that the strength of the concrete increased by 14.4% and 20.6%, respectively, for concrete without crushed sand (BSR0) and concrete with 50% crushed sand (BSR50) by increasing the curing age from 28 to 90 days. The static modulus of elasticity for conventional concrete BSR0 and BSR50 concrete with 50% crushed sand at 90 days was 23.7 and 21.8 GPa, respectively. Thus, combining crushed sand with alluvial sand is a good method to reduce the depletion of alluvial sands in Cameroon.

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Section: Gas Permeabilitysupporting

confidence: 93%

Microstructure and Mechanical Behavior of Concrete Based on Crushed Sand Combined with Alluvial Sand

et al. 2020

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“…However, only a few studies encompass improving the ITZ of the FRA concrete (FRAC) rather than the optimization of FRA in the concrete. Pereira et al (2012) and Berredjem et al (2020) infer that as the replacement of FRA increases, workability and strength of the concrete reduces, but upon addition of SP, the strength of the concrete was increased even at 100% replacement. The study reported that weakness of ITZ due to the higher porosity of FRA decreases the strength of FRAC.…”

Section: Introductionmentioning

confidence: 99%

Effect of fine recycled aggregate on the strength and durability properties of concrete modified through two-stage mixing approach

Sivamani

Renganathan

2021

Environ Sci Pollut Res

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To overcome the scarcity of river sand and dumping of construction and demolition wastes, the fine recycled aggregate (FRA) collected from C&D wastes is being utilized as a replacement to river sand. Many earlier studies reported that the higher water absorption of fine recycled aggregate and weak interfacial transition zone (ITZ) resulted in the development of the concrete with less strength and durability requirements. This study surmounts the above two factors through pre-saturation and a two-stage mixing approach (TSMA) technique. The concrete mixes prepared at 0.45 w/c ratios with 0%, 25%, 50%, and 100% of FRA were evaluated through hardened properties such as compressive strength, split tensile strength, flexural strength, and durability properties such as water absorption, sorptivity, shrinkage, rapid chloride penetration, and carbonation tests. The results indicate that the optimum level of replacement of fine recycled aggregate was 25% and the increase of fine recycled aggregate decreases the strength and durability properties. However, increased curing of concrete resulted in better strength and durability properties. The strength of the concrete was increased by 12% at 28 days and 17.46% at 90 days by two-stage mixing approach. The water absorption, porosity, shrinkage, chloride penetration, and carbonation of two-stage mixing approach was decreased by 7.45%, 15.38%, 16.57%, 18.18%, and 13.51% compared to normal mixing approach. Microstructural investigations show improvement in the interfacial transition zone with two-stage mixing approach compared to normal mixing approach.

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“…The presence of porous-adhered mortar with its high porosity and water absorption capacity may result in reduced workability and fresh-state performance for the same w/c ratio. This can be compensated for by pre-soaking the aggregates and/or adjusting the added water to account for the increase in water absorption of the RAs (Behera et al, 2014;Berredjem et al, 2020;Kapoor et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…These techniques have been demonstrated as being effective in mitigating the negative effects on durability of RAC, in terms of reduced resistance to chloride penetration, sulfate attack, carbonation penetration, and freeze-thaw cycles, attributed to the reasons outlined above (Zhu et al, 2016;Guo et al, 2018;Ma et al, 2019;Berredjem et al, 2020). The presence of higher CSH gel in RAC, because of higher binder content in the attached mortar, can also contribute to chloride binding (Guo et al, 2018).…”

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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Mechanical and durability properties of concrete based on recycled coarse and fine aggregates produced from demolished concrete

Cited by 108 publications

References 32 publications

Microstructure and Mechanical Behavior of Concrete Based on Crushed Sand Combined with Alluvial Sand

Microstructure and Mechanical Behavior of Concrete Based on Crushed Sand Combined with Alluvial Sand

Effect of fine recycled aggregate on the strength and durability properties of concrete modified through two-stage mixing approach

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

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