scholarly journals Dispersion of High Concentrations of Carbon Nanofibers in Portland Cement Mortars

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Joshua Hogancamp ◽  
Zachary Grasley
Keyword(s):  
Portland Cement ◽  
Carbon Nanofibers ◽  
Cement Mortar ◽  
Computational Simulation ◽  
Elastic Stiffness ◽  
Type I ◽  
Sem Image ◽  
Geometric Clustering ◽  
Microfine Cement ◽  
High Concentrations

This research focuses on creating and maintaining a stable dispersion of carbon nanofibers (CNFs) in portland cement based materials. A microfine cement is used in conjunction with an untraditional dispersion method to encourage and stabilize the dispersion of CNFs in concentrations up to 5% by mass of cement. A computational simulation was utilized to examine an effect called geometric clustering on the dispersion of CNFs among Type I/II and microfine cement grains. The geometric clustering simulation revealed a higher achievable dispersion for microfine cement than for Type I/II cement. Scanning electron microscopy (SEM) was used to quantify the dispersion of CNFs among Type I/II and microfine cement grains. SEM image analysis indicated excessive CNF clumping among Type I/II cement grains, while the dispersion of hybrid microfine cement mortar continued to improve as the concentration of CNFs increased up to 5% by mass of cement. Mortar cube elastic stiffness and mortar prism flexure tests revealed that high concentrations of CNFs had detrimental effects in hybrid Type I/II cement mortar, whereas similar concentrations of CNFs had negligible or beneficial effects in hybrid microfine cement mortar.

scholarly journals Investigation of the Optimal Percentage from Polyvinyl Alcohol on Flexural Strength of Cement Mortar Composite

2018 ◽  
Vol 7 (4.20) ◽  
pp. 584
Author(s):  
Waleed A. Abbas ◽  
Iqbal N. Korkess ◽  
Mahdi Jasim H.
Keyword(s):  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Portland Cement ◽  
Water Absorption ◽  
Cement Mortar ◽  
Alcohol Solution ◽  
Type I ◽  
Absorption Properties ◽  
Study Results ◽  
Packing Effect

Polyvinyl alcohol solution(PVA) proveded potential enhancement of the properties of cement mortar composite. This work investigated the effect of (w/c) and polymer-cement ratios (p/c) on the flexural strength of type I Portland cement mortar. A sand-cement ratio (s/c) of 1.25 and 0.5 by mass was used, and PVA powder was dispersed in water at (0.7%, 1%, 2%, and 3%) by weight of cement. The p/c solution was adjusted at five different values of 0.008, 0.012, 0.016, 0.020 and 30% covering relatively low and high values. Two types of curing were used; wet and dry curing. The study results demonstrated that flexural strength and significant water absorption properties of Portland cement mortar, as well as workability can be basically enhanced by the addition of PVA. Composite was prepared with optimum (p/c) 1.6% at concentration of 1% by mass under dry curing. The highest flexural strength was above twice the flexural strength of unmodified mortar. Also modified mortar samples illustrated that increasing of (p/c) causes reducing water absorption due to the packing effect caused by PVA, while mortar prepared at 0.1 and 0.3 w/c and (p/c) respectively, exhibited an increase in flexural strength which was more than the strength of unmodified mortar.  

Effect of Zeolite on Early Strength of Portland Cement Mortars

2019 ◽  
Vol 798 ◽  
pp. 358-363
Author(s):  
Raphat Tanasalagul ◽  
Thammaros Pantongsuk ◽  
Thapanee Srichumpong ◽  
Jaroon Junsomboon ◽  
Wichit Prakaypan ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortar ◽  
Testing Machine ◽  
Type I ◽  
X Ray Diffraction ◽  
Cement Mortars ◽  
Binder Ratio ◽  
Early Strength ◽  
Water To Binder Ratio

Portland cement consists essentially of compounds of lime mixed with silica and alumina whereas zeolite is a kind of minerals containing high content of reactive silica and alumina. Therefore, there is a probability to apply zeolite in cement mortar in order to develop mortar properties. The purpose of this research was to study and analyze the efficiency of zeolite addition on properties of cement mortar. X-ray diffraction (XRD), universal testing machine (UTM) and scanning electron microscope (SEM) were used to characterize for mortar specimens. Mechanical property test was compressive strength according to ASTM C109 and carried out on 5 x 5 x 5 cm3 cube specimens at 1, 7 and 28 curing days. In this research, cement mortars were prepared by mixing type I Portland cement, fly ash, sand and zeolite. Zeolite was varied as 0, 0.25, 0.50 and 0.75 wt.% to cement and w/b (water to binder ratio) was 0.48. The results presented that the compressive strength of mortar with small amount of zeolite was improved since 1day age obviously comparing to that of mortar without zeolite. It was confirmed that zeolite would help strengthening the cement mortars at early strength.

scholarly journals Study the Characterizations of Cement Mortar by Nano Pozzolanic Materials Additions

2018 ◽  
Vol 13 (4) ◽  
pp. 152-163 ◽  
Author(s):  
Fadhil A. Rasin ◽  
Laith K. Abbas ◽  
Mohammed J. Kadhim
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Mortar ◽  
Nano Particles ◽  
Type I ◽  
Fine Aggregate ◽  
Nano Materials ◽  
Curing Time ◽  
Water To Cement Ratio ◽  
Nano Alumina

This study involves adding nano materials and interaction with cement mortar behavior for several mortar samples under variable curing time with constant water to cement ratio (W/C = 0.5). The effects of adding nano materials on the microstructure of cement mortar were studied by (Scanning Electronic Microscopy (SEM) and X-Ray (for samples at different curing time 28 and 91 days. Small ratio replacements of nano particles (SiO2 or Al2O3) were added to Ordinary Portland Cement (OPC) type (I). The percentage of nano materials additives replacement by weight of ordinary Portland cement includes (1, 2, 3, 4 and 5%) for both types of nano materials with constant (W/C) ratio, also the amount of the fine aggregate used was three times the amount of cement. The results showed that, the mortar consist of both nano materials had better microstructure than mortar without nano materials in all test. Best enhancements in properties and microstructure for mortars with nano silica were achieved with (3%) additives while were achieved with nano alumina at (2%) additives.

scholarly journals Collagen-Based Electrospun Materials for Tissue Engineering: A Systematic Review

2021 ◽  
Vol 8 (3) ◽  
pp. 39
Author(s):  
Britani N. Blackstone ◽  
Summer C. Gallentine ◽  
Heather M. Powell
Keyword(s):  
Systematic Review ◽  
Tissue Engineering ◽  
Collagen Type I ◽  
The Body ◽  
Pool Data ◽  
Type I ◽  
High Concentrations ◽  
Increased Strength

Collagen is a key component of the extracellular matrix (ECM) in organs and tissues throughout the body and is used for many tissue engineering applications. Electrospinning of collagen can produce scaffolds in a wide variety of shapes, fiber diameters and porosities to match that of the native ECM. This systematic review aims to pool data from available manuscripts on electrospun collagen and tissue engineering to provide insight into the connection between source material, solvent, crosslinking method and functional outcomes. D-banding was most often observed in electrospun collagen formed using collagen type I isolated from calfskin, often isolated within the laboratory, with short solution solubilization times. All physical and chemical methods of crosslinking utilized imparted resistance to degradation and increased strength. Cytotoxicity was observed at high concentrations of crosslinking agents and when abbreviated rinsing protocols were utilized. Collagen and collagen-based scaffolds were capable of forming engineered tissues in vitro and in vivo with high similarity to the native structures.

scholarly journals Assessment of the influence of fine aggregates on Portland cement mortar compressive strength

2021 ◽  
pp. 100182
Author(s):  
Alberto Muciño ◽  
Lauro Bucio ◽  
Eligio Orozco ◽  
Sofía Vargas ◽  
Nora A. Pérez
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortar ◽  
Fine Aggregates

scholarly journals Impact of Substitute Portland Cement with CKD on the Mechanical and Durability Characteristics of Cement Mortar

2021 ◽  
Vol 1090 (1) ◽  
pp. 012035
Author(s):  
Duaa Al-Faluji ◽  
Muna M. Al-Rubaye ◽  
Mohammed Salah Nasr ◽  
Ali A. Shubbar ◽  
Zainab S. Al-Khafaji ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cement Mortar

Estimation of Portland cement mortar compressive strength using microcores. Influence of shape and size

2014 ◽  
Vol 55 ◽  
pp. 359-364 ◽  
Author(s):  
F.J. Alejandre ◽  
V. Flores-Alés ◽  
R. Villegas ◽  
J. García-Heras ◽  
E. Morón
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Mortar ◽  
Shape And Size
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