The use of microfine cement to enhance the efficacy of carbon nanofibers with respect to drying shrinkage crack resistance of portland cement mortars

2017 ◽  
Vol 83 ◽  
pp. 405-414 ◽  
Author(s):  
Joshua Hogancamp ◽  
Zachary Grasley
Keyword(s):  
Portland Cement ◽  
Crack Resistance ◽  
Carbon Nanofibers ◽  
Drying Shrinkage ◽  
Shrinkage Crack ◽  
Cement Mortars ◽  
Microfine Cement

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.

Fluid Transport Mechanisms in Portland Cement Mortar Modified with PVA and Nano Montmorillonite

2013 ◽  
Vol 687 ◽  
pp. 311-315 ◽  
Author(s):  
Teresa María Piqué ◽  
Luis Fernandez Luco ◽  
Analía Vázquez
Keyword(s):  
Tensile Strength ◽  
Portland Cement ◽  
Construction Industry ◽  
Fluid Transport ◽  
Cement Mortar ◽  
Drying Shrinkage ◽  
Cement Matrix ◽  
Poly Vinyl Alcohol ◽  
Cement Mortars ◽  
Compressive And Flexural Strengths

The development of new materials for specific applications is an increasing field in the construction industry, so is the employment of nanotechnology for this goal. When poly(vinyl alcohol) (PVA) is added to a Portland cement mortar, a film is formed in between the hydration products. This film has low elasticity modulus and high tensile strength and it enhances the mortar’s mechanical properties in the fresh and hardened states. The addition of nano montmorillonites (MMT) gives the polymer a better compatibility with the cement matrix. In this work, the changes in the microstructure of Portland cement mortars modified with PVA and PVA with MMT are assessed by means of transport of fluids capacity as an indicator. The reference is a standard mortar according to EN 196-1. The parameters measured are: weight loss under drying and air permeability. Complementary measures, such as compressive and flexural strengths and drying shrinkage have also been performed. From the obtained results, it can be concluded that the inclusion PVA + MMT to Portland cement mortar doesn’t affect the microstructure, when compared with Portland cement mortar with PVA, and even increase its tensile strength.

scholarly journals Strength and Drying Shrinkage of Alkali-Activated Slag Paste and Mortar

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mao-chieh Chi ◽  
Jiang-jhy Chang ◽  
Ran Huang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Liquid Slag ◽  
Drying Shrinkage ◽  
Curing Temperature ◽  
Alkali Activated Slag ◽  
Cement Mortars ◽  
Activated Slag ◽  
Alkali Activated

The aim of this study is to investigate the strengths and drying shrinkage of alkali-activated slag paste and mortar. Compressive strength, tensile strength, and drying shrinkage of alkali-activated slag paste and mortar were measured with various liquid/slag ratios, sand/slag ratios, curing ages, and curing temperatures. Experimental results show that the higher compressive strength and tensile strength have been observed in the higher curing temperature. At the age of 56 days, AAS mortars show higher compressive strength than Portland cement mortars and AAS mortars with liquid/slag ratio of 0.54 have the highest tensile strength in all AAS mortars. In addition, AAS pastes of the drying shrinkage are higher than AAS mortars. Meanwhile, higher drying shrinkage was observed in AAS mortars than that observed comparable Portland cement mortars.

Synthesis and application of methylcellulose extracted from waste newspaper in CPV-ARI Portland cement mortars

2010 ◽  
pp. n/a-n/a
Author(s):  
Geandre de Carvalho Oliveira ◽  
Guimes Rodrigues Filho ◽  
Júlia Graciele Vieira ◽  
Rosana M. Nascimento De Assunção ◽  
Carla da Silva Meireles ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cement Mortars

Influence of Crushed Basalt Aggregate on Crack Resistance of Concrete

2012 ◽  
Vol 253-255 ◽  
pp. 529-532
Author(s):  
Jian Jun Yan ◽  
Shi Hua Zhou ◽  
Shang Shi Peng
Keyword(s):  
Crack Resistance ◽  
Temperature Stress ◽  
Expansion Coefficient ◽  
Linear Expansion ◽  
Drying Shrinkage ◽  
Temperature Deformation ◽  
Linear Expansion Coefficient ◽  
Volume Deformation

The crack resistance of concrete with crushed basalt aggregate was studied. Compared with the limestone concrete, the basalt concrete has larger drying shrinkage and autogenous volume deformation. The linear expansion coefficient of basalt concrete is 1.3×10－6 /°C larger than that of limestone concrete, and it has additional temperature deformation of 24.1×10－6. According to the analysis on temperature-stress of concrete, the cracking temperature of basalt concrete is 8.9°C higher than that of limestone concrete, and the crack resistance of basalt concrete is unfavorable.

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