Recycling of Hardened Cementitious Material by Pressure and Control of Volumetric Change

Sakai, Yuya; Tarekegne, Biruktawit Taye; Kishi, Toshiharu

doi:10.3151/jact.14.47

Cited by 22 publications

(10 citation statements)

References 11 publications

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“…The porosity decreased significantly after the test under 400 MPa. In another study, hydrostatic pressure was applied on crushed HCP, which resulted in the plastic deformation of the powder, along with particle adherence [15]. These results show that porosity, which hinders SPM measurement, might be reduced by applying high pressure on cement paste.…”

Section: Introductionmentioning

confidence: 94%

Surface Properties of Cement Paste Evaluated by Scanning Probe Microscopy

Sakai¹

2016

OJCE

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The microscopic physical properties of Hardened Cement Paste (HCP) surfaces were evaluated by using Scanning Probe Microscopy (SPM). The cement pastes were cured under a hydrostatic pressure of 400 MPa and the contacting surfaces with a slide glass during the curing were studied. Scanning Electron Microscope (SEM) observation at a magnification of 7000 revealed smooth surfaces with no holes. The surface roughness calculated from the SPM measurement was 4 nm. The surface potential and the frictional force measured by SPM were uniform throughout the measured area 24 h after the curing. However, spots of low surface potential and stains of low frictional force and low viscoelasticity were observed one month after curing. This change was attributed to the carbonation of hydrates.

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Section: Introductionmentioning

confidence: 94%

Surface Properties of Cement Paste Evaluated by Scanning Probe Microscopy

Sakai¹

2016

OJCE

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“…Using recycled aggregates (RA) obtained from the construction industry or demolished buildings to replace raw aggregates in concrete design and production has become a new practice among recycling methods [17][18][19][20][21]. A problem associated with using recycled aggregates (RA) is the high porosity as well as the larger rate of water absorption in the concrete specimens, which are due to hydration of cement paste that is attached to RA, leading to reduced compressive strength and durability in concrete mixes [22]. However, new approaches have been introduced to improve the deficiency of recycled aggregates by reducing the amount of cement paste attached to RA [23,24].…”

Section: Introductionmentioning

confidence: 99%

Using Recycled Concrete Powder, Waste Glass Powder, and Plastic Powder to Improve the Mechanical Properties of Compacted Concrete: Cement Elimination Approach

Najaf

Abbasi

2022

Advances in Civil Engineering

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The environment receives millions of tons of garbage, including plastic and glass, and concrete building debris contributes to a number of environmental problems. In order to reduce cement and make use of waste materials like glass and plastic, this research creates compacted concrete samples using waste glass powder, waste plastic powder, micro-silica, fly ash, and recycled powdered concrete. Compressive, nonlinear behavior, and SEM tests on compacted specimens showed that by removing 80% of the cement and substituting 20% recycled concrete powder, 15% micro-silica, 15% fly ash, 15% waste plastic powder, and 15% waste glass powder (at 80°C for 20 minutes), sustainable concrete with compressive and flexural strengths nearly equal to the sample’s compressive and flexural strengths was produced. Micro-silica has several shortcomings regarding improving concrete strength and building a suitable combination with recycled concrete powder. In extremely small quantities, glass powder may be used to replace cement, and in greater quantities, it can take the place of aggregate. Finally, it was found that concrete mortar could be made completely sustainable by using recycled materials like glass, plastic, and recycled concrete, as well as micro-silica and fly ash, and that only 20% of the weight of cement could be used without lowering the compressive and flexural strength of the concrete.

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“…The hardness and modulus of elasticity of the hydrated Portland cement compacts appeared to be the same as that of original cement paste before crushing and compacting when the total pore volume was the same [3]. Therefore, powder compaction was proposed as a sustainable way to recycle concrete waste [4]. Studies on recycling concrete waste by powder compaction suggest that the required compaction pressure for this method is quite high to achieve the applicable strength in construction [5].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Bending Strength of Recycled Concrete and Wooden Waste by Heating Compaction

L¹,

Sakai²

2020

Preprint

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A large amount of concrete waste is generated around the world and its recycling is an urgent issue. In this research, a new approach to recycle concrete waste with wooden waste was studied. Concrete and wooden wastes were crushed, mixed, and heat compacted to produce plates with different water contents and mix proportions at various temperatures, pressures, and durations of compaction. The bending strength of the plates was measured after compaction. The result indicated that with an increase in the percentage of wooden waste in the mixture, pressure, or temperature improved the bending strength. The increase in water content reduced the bending strength. Most of the products exhibited higher bending strength than that of ordinary concrete.

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Recycling of Hardened Cementitious Material by Pressure and Control of Volumetric Change

Cited by 22 publications

References 11 publications

Surface Properties of Cement Paste Evaluated by Scanning Probe Microscopy

Surface Properties of Cement Paste Evaluated by Scanning Probe Microscopy

Using Recycled Concrete Powder, Waste Glass Powder, and Plastic Powder to Improve the Mechanical Properties of Compacted Concrete: Cement Elimination Approach

Experimental Study of the Bending Strength of Recycled Concrete and Wooden Waste by Heating Compaction

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