scholarly journals Influence of Polyethylene Terephthalate Powder on Hydration of Portland Cement

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2551
Author(s):  
Min Ook Kim ◽  
Jun Kil Park ◽  
Taek Hee Han ◽  
Joonho Seo ◽  
Solmoi Park
Keyword(s):  
Portland Cement ◽  
Polyethylene Terephthalate ◽  
Cement Paste ◽  
Pore Solution ◽  
Isothermal Calorimetry ◽  
Test Results ◽  
X Ray Diffraction ◽  
Replacement Ratio ◽  
Chemical Changes ◽  
X Ray

The management of plastic waste is a massive challenge and the recycling of plastics for newer applications is a potential solution. This study investigates the feasibility of using polyethylene terephthalate (PET) powder in cementitious composites. The changes in the strength and microstructure of Portland cement incorporating PET powder with different replacement ratios were systematically analyzed through the measurements of compressive strength, isothermal calorimetry, X-ray diffraction, thermogravimetric analysis, and Raman spectroscopy. In addition, the possible chemical changes of cement paste samples were studied upon exposure to different conditions, including deionized water, seawater, and simulated pore solution. Based on the test results and analysis, no apparent chemical changes were observed in the cement paste samples, regardless of the exposure conditions. In contrast, the PET powder incorporated into concrete exhibited remarkable changes, which may have occurred during the mixing process. The results also suggested that the maximum replacement ratio of PET powder should be less than 10% of the binder (by mass) to minimize its influence on cement hydration, due to the interaction between water and PET. The PET-containing samples showed the presence of calcium aluminate hydrates which were absent in the neat paste sample.

Erosion Phases in Two Types of Cement Pastes Containing Limestone Exposed to Sulfate Attack

2014 ◽  
Vol 584-586 ◽  
pp. 1182-1187 ◽  
Author(s):  
Feng Chen Zhang ◽  
Yun Zhao ◽  
Fu Wan Zhu
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Limestone Powder ◽  
Test Results ◽  
X Ray Diffraction ◽  
Limestone Filler ◽  
Cement Pastes ◽  
Cement Production ◽  
X Ray ◽  
Gypsum Formation

Limestone filler and aggregates are used widely in cement production and concrete mixing nowadays, which could be connected with thaumasite formation, and lead to a lack of durability further. This work deals with the sulfate minerals including of thaumasite, ettringite and gypsum in two types of cement pastes containing 35% w/w limestone powder immersed in MgSO4 solution at 5°C±2°C for 15 weeks by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). Two types of cements were used: (i) ordinary Portland cement (P·O), (ii) typeII Portland cement (P·II). Test results show that thaumasite is present in two types of cement pastes, amount of thaumasite as well as amount of portlandite reacted with external SO42- in P·II cement paste are more than those in P·O cement paste. It indicates that P·II cement is more susceptible to thaumasite formation than P·O cement containing the same amount of limestone powder, and more gypsum formation could contribute to thaumasite formation possibly during the external MgSO4 attack at low temperature.

scholarly journals Chloride-Binding Capacity of Portland Cement Paste Blended with Synthesized CA2 (CaO·2Al2O3)

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yunsu Lee ◽  
Mingyun Kim ◽  
Zhengxin Chen ◽  
Hanseung Lee ◽  
Seungmin Lim
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Binding Capacity ◽  
Water Soluble ◽  
Chloride Binding ◽  
X Ray Diffraction ◽  
Total Chloride ◽  
X Ray ◽  
Isotherm Equation ◽  
Portland Cement Paste

A chloride-binding capacity is the major factor to mitigate the ingress of chloride into concrete. This paper presents the chloride-binding capacity of Portland cement paste containing synthesized CA2 (CaO·2Al2O3). The CA2 was synthesized in the high-temperature furnace and characterized by X-ray diffraction for inspecting the purity. The synthesized CA2 was substituted for Portland cement by 0%, 5%, and 10% by weight, and the NaCl solution was used as an internal chloride, which is assumed as a total chloride. The chloride-binding capacity of cement paste was calculated from a water-soluble chloride extraction method by the application of the Langmuir isotherm equation. And the hydration products were analyzed using X-ray diffraction and thermogravimetric analysis. We demonstrate that the CA2 increases an AFm phase in the Portland cement system, and the incorporation of CA2 consequently enhances the chloride-binding capacity of cement paste samples.

scholarly journals Effect of Metakaolin on Strength and Efflorescence Quantity of Cement-Based Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Tsai-Lung Weng ◽  
Wei-Ting Lin ◽  
An Cheng
Keyword(s):  
Compressive Strength ◽  
Image Analysis ◽  
Portland Cement ◽  
Detrimental Effect ◽  
Cement Mortar ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Replacement Ratio ◽  
X Ray ◽  
Scanning Electron

This study investigated the basic mechanical and microscopic properties of cement produced with metakaolin and quantified the production of residual white efflorescence. Cement mortar was produced at various replacement ratios of metakaolin (0, 5, 10, 15, 20, and 25% by weight of cement) and exposed to various environments. Compressive strength and efflorescence quantify (using Matrix Laboratory image analysis and the curettage method), scanning electron microscopy, and X-ray diffraction analysis were reported in this study. Specimens with metakaolin as a replacement for Portland cement present higher compressive strength and greater resistance to efflorescence; however, the addition of more than 20% metakaolin has a detrimental effect on strength and efflorescence. This may be explained by the microstructure and hydration products. The quantity of efflorescence determined using MATLAB image analysis is close to the result obtained using the curettage method. The results demonstrate the best effectiveness of replacing Portland cement with metakaolin at a 15% replacement ratio by weight.

scholarly journals Rheology, Hydration, and Microstructure of Portland Cement Pastes Produced with Ground Açaí Fibers

2021 ◽  
Vol 11 (7) ◽  
pp. 3036
Author(s):  
Afonso Azevedo ◽  
Paulo de Matos ◽  
Markssuel Marvila ◽  
Rafael Sakata ◽  
Laura Silvestro ◽  
...  
Keyword(s):  
Portland Cement ◽  
Yield Stress ◽  
Chemical Treatment ◽  
Isothermal Calorimetry ◽  
Natural Fibers ◽  
Euterpe Oleracea ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray ◽  
Fiber Characterization

Açaí (Euterpe oleracea) is a Brazilian typical fruit that is enveloped by natural fibers. This work investigated the effect of incorporating ground açaí fibers (in natura and chemically treated with NaOH and HCl) in 5–10 wt.% replacement of Portland cement on the rheology, hydration, and microstructure of pastes. Rotational rheometry, isothermal calorimetry, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) were performed to evaluate the cement pastes, in addition to SEM-EDS, FTIR, zeta potential, and XRD for fiber characterization. The results showed that the chemical treatment reduced the cellulose and lignin contents in açaí fibers while increasing its surface roughness. The addition of 5% of either fiber slightly increased the yield stress and viscosity of paste, while 10% addition drastically increased these properties, reaching yield stress and viscosity values respectively 40 and 8 times higher than those of plain paste. The incorporation of 5% in natura fibers delayed the cement hydration by about 2.5 days while 10% in natura fibers delayed it by over 160 h. The chemical treatment significantly reduced this retarding effect, leading to a 3 h delay when 5% treated fibers were incorporated. Overall, the combined NaOH/HCl treatment was effective for açaí fibers functionalization and these fibers can be used in cementitious composites.

Transient liquid phase bonding of Cu and Al using metallic particles interlayers

2021 ◽  
pp. 095440542098823
Author(s):  
Alireza Zaheri ◽  
Mohammadreza Farahani ◽  
Alireza Sadeghi ◽  
Naser Souri
Keyword(s):  
Liquid Phase ◽  
Mechanical Test ◽  
Transient Liquid Phase ◽  
Transient Liquid Phase Bonding ◽  
Joint Interface ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallic Particles ◽  
Powder Interlayer

The bonding strength, and microstructures of Cu and Al couples using metallic powders as interlayer during transient liquid phase bonding (TLP bonding) were investigated. The interfacial morphologies and microstructures were studied by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and X-ray diffraction. First, to explore the optimum bonding time and temperature, nine samples were bonded without interlayers in a vacuum condition. Mechanical test results indicated that bonding at 560°C in 20 min returns the highest bond strength (84% of Al). This bonding condition was used to join ten samples with powder interlayers. Powders were prepared by mixing different combinations of Cu, Al (+Fe nanoparticles) and Zn. In the bonding zone, different Cu9Al4, CuAl, and CuAl2 intermetallic co-precipitate. The strongest bonding is formed in the sample with the 70Al (+Fe)-30Cu powder interlayer. Powder interlayers present thinner and more uniform intermetallic layers at the joint interface.

scholarly journals Mineralogical stabilization of Ternesite in Belite Sulfo-Aluminate Clinker elaborated from limestone, shale and phosphogypsum

2018 ◽  
Vol 149 ◽  
pp. 01073
Author(s):  
K. Ben Addi ◽  
A. Diouri ◽  
N. Khachani ◽  
A. Boukhari
Keyword(s):  
Infrared Spectroscopy ◽  
Phosphoric Acid ◽  
Portland Cement ◽  
Stability Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability

This paper investigates the mineralogical evolution of sulfoaluminate clinker elaborated from moroccan prime materials limestone, shale and phosphogypsum as a byproduct from phosphoric acid factories. The advantage of the production of this type of clinker is related to the low clinkerisation temperature which is known around 1250°C, and to less consumption quantity of limestone thus enabling less CO2 emissions during the decarbonation process compared to that of Portland cement. In this study we determine the stability conditions of belite sulfoaluminate clinker containing belite (C2S) ye’elimite (C4A3$) and ternesite (C5S2$). The hydration compounds of this clinker are also investigated. The monitoring of the synthesized and hydrated phases is performed by X-Ray Diffraction and Infrared spectroscopy. The results show the formation of ternesite at 800°C and the stabilization of clinker containing y’elminite, belite and ternesite at temperatures between 1100 and 1250°C.

scholarly journals Portland clinker with civil construction waste: influence of pellet geometry on the formation of crystalline phases

2020 ◽  
Vol 20 (4) ◽  
pp. 205-223
Author(s):  
Fernanda Nepomuceno Costa ◽  
Daniel Véras Ribeiro ◽  
Cléber Marcos Ribeiro Dias
Keyword(s):  
Sustainable Development ◽  
Portland Cement ◽  
Rietveld Method ◽  
Industrial Process ◽  
3D Printer ◽  
New Materials ◽  
X Ray Diffraction ◽  
Construction Waste ◽  
X Ray ◽  
Portland Cement Association

Abstract Efforts to reduce greenhouse gas emissions in the context of sustainable development have intensified, with the development of research aimed at the production of new materials and binders for construction. This article analyzes the influence of pellet geometry in the production of clinkers, with the incorporation of construction waste (CCW). Procedures adapted from the method proposed by Brazilian Portland Cement Association were adopted in studies of laboratory clinkers, in an attempt to simulate the stages of the industrial process. Pellets were prepared with the same formulation, however, with four different geometries: spherical, with diameters of 1 cm, 2 cm and 3 cm, with manual molding, and semi-spherical, with a diameter of 2 cm, using molds of PLA (polylactic acid) printed on a 3D printer to facilitate the molding of the clinkers in a standardized way. Clinkers were characterized mineralogically by x-ray diffraction (XRD) and the Rietveld method was used to quantify the phases. Variations in the quantities of the alite and belite phases were observed depending on the geometry of the pellets, although the same calcination conditions were used. This is probably due to the variation in the surface area (exposure area) and the gradients of the cooling rate.

Anti-ultraviolet and anti-static modification of polyethylene terephthalate fabrics with graphene nanoplatelets by a high-temperature and high-pressure inlaying method

2018 ◽  
Vol 89 (8) ◽  
pp. 1488-1499 ◽  
Author(s):  
Cheng Zhang ◽  
Ling Zhong ◽  
Dingfei Wang ◽  
Fengxiu Zhang ◽  
Guangxian Zhang
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Polyethylene Terephthalate ◽  
Fiber Surface ◽  
Graphene Nanoplatelets ◽  
X Ray Diffraction ◽  
Static Properties ◽  
Protection Factor ◽  
X Ray ◽  
Pet Fabric

Grafting graphene on polyethylene terephthalate (PET) fibers requires a large number of environmentally harmful chemicals. In this study, a facile high-temperature and high-pressure method of inlaying graphene nanoplatelets was applied to fabricate anti-ultraviolet (UV) and anti-static graphene/PET composites. The resulting graphene-inlaid (GI) PET fabric, which showed excellent anti-ultraviolet and anti-static properties, was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform–infrared spectroscopy and X-ray diffraction. Results suggested that graphene had been inlaid into the PET fiber surface, and that the optimal inlaying conditions were as follows: inlaying temperature 200℃, inlaying pressure 15 MPa, and inlaying time 15 s. The UV protection factor of the GI PET fabric under optimal conditions could reach 50+ and was maintained at 50+ after 50 laundering cycles. The peak values of the static voltage and its half-time in the GI PET fabric could be reduced from 500.0 V to 10.0 V and from 7.39 s to 0.53 s, respectively, and the electrical resistivity of the GI PET fabric was 36.04 ± 0.14 kΩ.cm. The breaking strengths of the GI PET fabrics could be retained over 70.0% that of the pure PET fabric. The facile high-temperature and high-pressure inlaying method is an eco-friendly technique that requires very few chemicals, except for ethyl alcohol.

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