Accelerating electrochemical repair rate for cracked cement composites: Effect of carbon nanofiber

2021 ◽  
Vol 312 ◽  
pp. 125349
Author(s):  
Qian Zhang ◽  
Lianwang Yuan ◽  
Zonghui Zhou ◽  
Jinbang Wang
Keyword(s):  
Carbon Nanofiber ◽  
Cement Composites ◽  
Repair Rate

scholarly journals Performance of carbon nanofiber-cement composites subjected to accelerated decalcification

2013 ◽  
Vol 56 ◽  
pp. 02005 ◽  
Author(s):  
L. Brown ◽  
F. Sanchez ◽  
D. Kosson ◽  
J. Arnold
Keyword(s):  
Carbon Nanofiber ◽  
Cement Composites

Early-Age Performance of 3D Printed Carbon Nanofiber and Carbon Microfiber Cement Composites

2020 ◽  
Vol 2674 (2) ◽  
pp. 10-20 ◽  
Author(s):  
M. Kosson ◽  
L. Brown ◽  
F. Sanchez
Keyword(s):  
3D Printing ◽  
Carbon Nanofiber ◽  
Interfacial Region ◽  
Cement Composites ◽  
Cast Composites ◽  
Lubrication Layer ◽  
3D Printed ◽  
Carbon Microfiber ◽  
Strength Difference ◽  
Air Cavities

3D printed cement composites with and without carbon nanofiber (CNF) and microfiber (CF) reinforcement within the cement ink were evaluated at seven days and compared with their traditionally cast counterparts. A liquid lubrication layer at the extrusion nozzle was noted. The reinforcement type influenced the formation of the extruded filament, with underextrusion seen during 3D printing with the CNF cement ink while sudden discontinuation of extrusion was experienced during 3D printing with the CF cement ink. No noticeable interfacial region between printed filaments was observed in the 3D printed cement composites, with the exception of air cavities between printed filaments of the composite fabricated with the CNF cement ink. Lower compressive strengths were seen in the direction orthogonal to the print path for the 3D printed composites compared with the cast composites. The addition of CFs within the cement ink reduced this strength difference and led to strain softening in the post peak behavior.

Graphene Nanoplatelets-Based Self-Sensing Cementitious Composites

2016 ◽  
Author(s):  
Zhangfan Jiang ◽  
Osman E. Ozbulut ◽  
Devin K. Harris
Keyword(s):  
Carbon Nanofiber ◽  
Low Cost ◽  
Graphene Nanoplatelets ◽  
Cementitious Composites ◽  
Cement Composites ◽  
The Past ◽  
Compressive Loads ◽  
Reinforced Cement ◽  
Functional Fillers ◽  
Significant Attention

Over the past two decades, numerous research studies have been conducted to explore behavior of self-sensing cementitious composites with different functional fillers. Most of these studies investigated the use of fillers such as carbon nanofiber (CNF), carbon black, and carbon nanotubes (CNTs) in cement composites to develop a multifunctional material. Since its discovery in 2004, graphene has also raised significant attention as 2D nanoscale reinforcement for composite materials. The planar structure of graphene sheets provides more contact area with the host material. However, high cost and dispersion difficulties are among the drawbacks of graphene. More recently, graphene nanoplatelets (GNPs), which have very thin but wide aspect ratio, are drawing the graphene market due to their advantages such as ease of processing and excellent material properties at a very low cost. The application of two-dimensional graphene nanoplatelets in cementitious composites has yet to gain widespread attention. This paper investigates the self-sensing capabilities of GNP-reinforced hydraulic Portland cement composites. In particular, the effects of GNP content on the electrical properties and piezoresistive characteristics of mortar specimens are explored. In addition, a simple fabrication method that does not require special treating procedures such as ultrasonication and chemical (covalent) treatments for the dispersion of GNPs is pursued. The GNPs used in this study have an average thickness of 8 nanometers and a diameter of 25 microns. Standard prismatic mortar specimens containing different GNP concentrations are prepared using three different mixing procedures. The resistivity of the specimens is measured using a four-point probe method. The piezoresistive response of GNP-reinforced cement composites is evaluated under cyclic compressive loads.

Cytocompatibility of Carbon Nanofiber Materials for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Carbon Fiber ◽  
Surface Energy ◽  
Carbon Nanofibers ◽  
Carbon Fibers ◽  
Carbon Nanofiber ◽  
Fiber Composite ◽  
Scar Tissue ◽  
Pc 12 Cells ◽  
Low Surface Energy ◽  
Poly Carbonate

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.

Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanofibers ◽  
Material Properties ◽  
Carbon Nanofiber ◽  
Scar Tissue ◽  
Tissue Response ◽  
Positive Interactions ◽  
Weight Percentage ◽  
Poly Carbonate

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.

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