Nanomaterials in recycled aggregates concrete applications: mechanical properties and durability. A review

Allujami, Hamzeh Marwan; Abdulkareem, Muyideen; Jassam, Taha M.; Al-Mansob, Ramez A.; Ng, Jing Lin; Ibrahim, Abu Bakar

doi:10.1080/23311916.2022.2122885

Cited by 17 publications

(6 citation statements)

References 143 publications

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“…Secondly, since innovative structures are anticipated to have longer service lives, their greater durability results in a reduction in the average yearly cement usage [65]. Last but not least, recent technical developments in the manufacture of nanostructured materials, and particularly in nanoparticles, have started to use atoms of carbon for gases such as carbon dioxide, which might also help in reducing atmospheric carbon dioxide levels [66]. The widespread usage of CN-CBCs in the civil engineering sector would provide a means of achieving this goal [67].…”

Section: Aspects Involving Improved Carbon Nanoparticles Made Of Ceme...mentioning

confidence: 99%

The Effects of Nano-Based Bio-Carbonates in Superhydrophobic Concrete—A Review

et al. 2023

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Concrete must be a hydrophilic compound that is easily fabricated by nature. At the nanoscale, mechanical and chemical reactions alter the quality of cement-based substances. Continuous sprinkling of nano-silica solution synthesised with minimal surface solvents has been used to create a superhydrophobic (SH) concrete surface while similarly modifying the surface’s chemical composition and dynamical intrinsic structure. In this study, we examine the impacts of admixtures in SH concrete including nano-based bio-carbonate. The fundamental characteristics and dispersal techniques of nanoparticles often employed in cement-based compounds are reviewed initially in this paper. Investigations of the large contact angle, small slide angle, and carbonated thickness have been employed to analyze the impacts of admixtures. Additionally, the industry and uses of nanoparticles for concrete substances are addressed, and the expense is inventively represented by a survey questionnaire. Finally, this article identifies the obstacles that now occur in the field of research and offers appropriate future viewpoints.

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Section: Aspects Involving Improved Carbon Nanoparticles Made Of Ceme...mentioning

confidence: 99%

The Effects of Nano-Based Bio-Carbonates in Superhydrophobic Concrete—A Review

et al. 2023

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“…The mechanisms by which micro- and nanosilica act in cement systems with recycled aggregates are similar to those presented in the case of using natural aggregates. The difference in the case of using recycled aggregates is that micro- and nanosilica act mainly in the interfacial transition zone (ITZ) around the aggregate granules by densifying and reducing the porosity of the old mortar attached to the natural aggregate [ 21 ]. One cement system made with recycled aggregates is represented by special mortars for encapsulating low-level radioactive waste (LLW).…”

Section: Introductionmentioning

confidence: 99%

Effects of Micro- and Nanosilica on the Mechanical and Microstructural Characteristics of Some Special Mortars Made with Recycled Concrete Aggregates

Mazilu,

Deju,

Georgescu

et al. 2024

Materials

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In this paper, we study the influence of densified microsilica and colloidal nanosilica admixtures on the mechanical strength and the microstructural characteristics of special mortars used for immobilizing radioactive concrete waste. The experimental program focused on the replacement of cement with micro- and/or nanosilica, in different proportions, in the basic composition of a mortar made with recycled aggregates. The technical criteria imposed for such cementitious systems, used for the encapsulation of low-level radioactive waste, imply high fluidity, increased mechanical strength and lack of segregation and of bleeding. We aimed to increase the structural compactness of the mortars by adding micro- and nanosilica, all the while maintaining the technical criteria imposed, to obtain a cement matrix with high durability and increased capacity for immobilizing radionuclides. The samples from all the compositions obtained were analyzed from the point of view of mechanical strength. Also, micro- and nanosilica as well as samples of the optimal mortar compositions were analyzed physically and microstructurally. Experimental data showed that the mortar samples present maximum compressive strength for a content between 6 and 7.5% wt. of microsilica, respectively, for a content of 2.25% wt. nanosilica. The obtained results suggest a synergistic effect of micro- and nanosilica when they are used simultaneously in cementitious compositions. Thus, among the analyzed compositional variants, the mortar composition with 3% wt. microsilica and 2.25% wt. nanosilica showed the best performance, with an increase in compressive strength of 23.5% compared to the control sample (without micro- and nanosilica). Brunauer–Emmett–Teller (BET) analysis and scanning electron microscopy (SEM) images highlighted the decrease in pore diameter and the increase in structural compactness, especially for mortar samples with nanosilica content or a mixture of micro- and nanosilica. This study is useful in the field of recycling radioactive concrete resulting from the decommissioning of nuclear research or nuclear power reactors.

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“…This is due to RAC&D having adhered to the old mortar with lower density, higher porosity, lower crush resistance, higher water absorption value and weaker interfacial transition zones (ITZs) [ 5 , 12 , 30 , 31 ]. Therefore, the development of new techniques to improve the quality of RAC&D is on the rise [ 27 , 32 , 33 , 34 , 35 , 36 , 37 ], among which are those that improve the quality of RAC&D by using CO 2 (accelerated carbonation), which seems to be a very promising technology [ 38 , 39 , 40 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

et al. 2023

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The objective of the present study was to explore three types of vibro-compacted precast concrete mixtures replacing fine and coarse gravel with a recycled/mixed concrete aggregate (RCA or MCA). The portlandite phase found in RCA and MCA by XRD is a “potential” CO2 sink. CO2 curing improved the compressive strength in all the mixtures studied. One tonne of the mixtures studied could be decarbonised after only 7 days of curing 13,604, 36,077 and 24,635 m3 of air using natural aggregates, RCA or MCA, respectively. The compressive strength obtained, XRD, TGA/DTA and carbon emission evaluation showed that curing longer than 7 days in CO2 was pointless. The total CO2 emissions by a mixture using CO2 curing at 7 days were 221.26, 204.38 and 210.05 kg CO2 eq/m3 air using natural aggregates, RCA or MCA, respectively. The findings of this study provide a valuable contribution to carbon emission evaluation of CO2 curing in vibro-compacted precast concrete with recycled/mixed concrete aggregates (RCA or MCA). The technology proposed in this research facilitates carbon capture and use and guarantees enhanced compressive strength of the concrete samples.

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Nanomaterials in recycled aggregates concrete applications: mechanical properties and durability. A review

Cited by 17 publications

References 143 publications

The Effects of Nano-Based Bio-Carbonates in Superhydrophobic Concrete—A Review

The Effects of Nano-Based Bio-Carbonates in Superhydrophobic Concrete—A Review

Effects of Micro- and Nanosilica on the Mechanical and Microstructural Characteristics of Some Special Mortars Made with Recycled Concrete Aggregates

Carbon Emission Evaluation of CO2 Curing in Vibro-Compacted Precast Concrete Made with Recycled Aggregates

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