May the Piezoresistivity of GNP-Modified Cement Mortar Be Related to Its Fractal Structure?

2021 ◽  
Vol 5 (4) ◽  
pp. 148
Author(s):  
Nanxi Dang ◽  
Jin Tao ◽  
Qiang Zeng ◽  
Weijian Zhao
Keyword(s):  
Fractal Structure ◽  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Fractal Dimensions ◽  
Gauge Factor ◽  
Mercury Intrusion ◽  
Multi Scale ◽  
Fractal Models ◽  
Cement Mortars ◽  
Electron Scanning Microscopy

High piezoresistivity of cement-based composites tuned by conductible fillers provides a feasible way to develop self-sensing smart structures and buildings. However, the microstructural mechanisms remain to be properly understood. In the present work, the piezoresistivity of cement mortar with different dosages of graphene nanoplatelets (GNPs) was investigated, and the microstructure was assessed by electron scanning microscopy (SEM) and mercury intrusion porosimetry (MIP). Two surface fractal models were introduced to interpret the MIP data to explore the multi-scale fractal structure of the GNP-modified cement mortars. Results show that the incorporation of GNPs into cement mortar can roughen the fracture surfaces due to the GNPs’ agglomeration. Gauge factor (GF) rises and falls as GNP content increases from 0% to 1% with the optimal piezoresistivity observed at GNP = 0.1% and 0.05%. The GF values of the optimum mortar are over 50 times higher than those of the reference mortar. Fractal dimensions in macro and micro fractal regions change with GNP content. Analysis shows that the fractal dimensions in micro region decrease first and then increase with the increase of GF values. GNPs not only impact the fractal structure of cement mortar, but also alter the tunneling and contact effects that govern the piezoresistivity of composite materials.

scholarly journals Effect of Hydrogen Nanobubbles on the Mechanical Strength and Watertightness of Cement Mixtures

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1823
Author(s):  
Won-Kyung Kim ◽  
Young-Ho Kim ◽  
Gigwon Hong ◽  
Jong-Min Kim ◽  
Jung-Geun Han ◽  
...  
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Stable State ◽  
Pozzolanic Reaction ◽  
Hydration Reaction ◽  
High Concentration ◽  
Mercury Intrusion ◽  
Electron Microscope Analysis ◽  
Mixing Water ◽  
Cement Mixtures

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the cement mortar for each curing day was improved by about 3.7–15.79%, compared to the specimen that used general water, when two concentrations of HNBW were used as the mixing water. The results of mercury intrusion porosimetry and a scanning electron microscope analysis of the cement paste showed that the pore volume of the specimen decreased by about 4.38–10.26%, thereby improving the watertightness when high-concentration HNBW was used. The improvement in strength and watertightness is a result of the reduction of the microbubbles’ particle size, and the increase in the zeta potential and surface tension, which activated the hydration reaction of the cement and accelerated the pozzolanic reaction.

Research On The Fractal and Percolation Characteristics of Coal-Based Porous Media For Filtration and Impregnation

2021 ◽  
Author(s):  
Qili Wang ◽  
Jiarui Sun ◽  
Yuehu Chen ◽  
Yuyan Qian ◽  
Shengcheng Fei ◽  
...  
Keyword(s):  
Porous Media ◽  
Fractal Structure ◽  
Mercury Intrusion Porosimetry ◽  
Fractal Theory ◽  
Fractal Dimensions ◽  
Infinite Cluster ◽  
Porous Graphite ◽  
Local Aggregation ◽  
Gradual Expansion ◽  
The Difference

Abstract In order to distinguish the difference in the heterogeneous fractal structure of porous graphite used for filtration and impregnation, the fractal dimensions obtained through the mercury intrusion porosimetry (MIP) along with the fractal theory were used to calculate the volumetric FD of the graphite samples. The FD expression of the tortuosity along with all parameters from MIP test was optimized to simplify the calculation. In addition, the percolation evolution process of mercury in the porous media was analyzed in combination with the experimental data. As indicated in the analysis, the FDs in the backbone formation regions of sample vary from 2.695 to 2.984, with 2.923 to 2.991 in the percolation regions and 1.224 to 1.544 in the tortuosity. According to the MIP test, the mercury distribution in porous graphite manifested a transitional process from local aggregation, gradual expansion, and infinite cluster connection to global connection.

Cement render and mortar and their damages due to salt crystallization in the Holy Trinity Dominicans monastery in Cracow, Poland

2020 ◽  
Author(s):  
Mariola Marszałek ◽  
Krzysztof Dudek ◽  
Adam Gaweł ◽  
Jerzy Czerny
Keyword(s):  
Laboratory Tests ◽  
Mercury Intrusion Porosimetry ◽  
Cement Mortar ◽  
Salt Crystallization ◽  
Secondary Minerals ◽  
X Ray ◽  
Mercury Intrusion ◽  
Holy Trinity ◽  
Micro Raman Spectroscopy ◽  
Jurassic Limestone

<p>The presented investigations are focused on a part of the 13<sup>th</sup> century Church of the Holy Trinity Dominicans monastery in Cracow, Poland, and include the wall façade of the 17<sup>th </sup>century Myszkowski chapel. The chapel was probably designed by Santi Gucci Fiorentino and built by his workshop. Southern façade of the chapel is made of Tertiary limestone blocks that make characteristic rusticated wall. Lower part of the façade is covered with cement and the basement is made of irregular fragments of Jurassic limestone and Cretaceous sandstone partly replaced and bound with cement mortar. The façade revealed clear signs of damage ranging from dark gray soiling of the surface, scaling to efflorescences. The last ones – mainly on the border of limestone blocks and the cement in the part of the basement.</p><p>Laboratory tests included mineralogical, chemical and petrophysical analyses. Optical microscopy, scanning electron microscopy (SEM-EDS), micro-Raman spectroscopy and X-ray diffractometry (XRD) were used for analysing materials and deterioration products of the cement render and mortar. The petrophysical properties of the materials have been performed using mercury intrusion porosimetry. The secondary minerals detected include mainly gypsum CaSO<sub>4</sub>·2H<sub>2</sub>O, thenardite Na<sub>2</sub>SO<sub>4</sub>, <sub> </sub>aphthitalite (Na,K)<sub>3</sub>Na(SO<sub>4</sub>)<sub>2</sub>, darapskite, Na<sub>3</sub>(SO<sub>4</sub>)(NO<sub>3</sub>)·H<sub>2</sub>O, nitre KNO<sub>3</sub>, nitratine NaNO<sub>3</sub>, ettringite Ca<sub>6</sub>Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>(OH)<sub>12</sub>·26H<sub>2</sub>O and monosulphite Ca<sub>4</sub>Al<sub>2</sub>O<sub>6</sub>SO<sub>3</sub>·11H<sub>2</sub>O. Lower blocks of the façade covered with cement contain chiefly gypsum, ettringite and monosulphite, cement from the basement – gypsum and nitre; while efflorescences – thenardite, aphthitalite, darapskite, nitre and nitratine. The origin of the salts have been discussed and the differences in their type have been associated with composition of the materials and their physicochemical properties.</p><p>This work has been financially supported by the AGH University of Science and Technology, statutory grant no. 16.16.140.315.</p>

scholarly journals Fractal Analysis of Microscale and Nanoscale Pore Structures in Carbonates Using High-Pressure Mercury Intrusion

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Fuyong Wang ◽  
Peiqing Lian ◽  
Liang Jiao ◽  
Zhichao Liu ◽  
Jiuyu Zhao ◽  
...  
Keyword(s):  
High Pressure ◽  
Capillary Tube ◽  
Fractal Dimensions ◽  
Tube Model ◽  
Permeability Model ◽  
Mercury Intrusion ◽  
Fractal Models ◽  
Capillary Tube Model ◽  
Fractal Characteristics ◽  
Nanoscale Pore

This paper investigated fractal characteristics of microscale and nanoscale pore structures in carbonates using High-Pressure Mercury Intrusion (HPMI). Firstly, four different fractal models, i.e., 2D capillary tube model, 3D capillary tube model, geometry model, and thermodynamic model, were used to calculate fractal dimensions of carbonate core samples from HPMI curves. Afterwards, the relationships between the calculated fractal dimensions and carbonate petrophysical properties were analysed. Finally, fractal permeability model was used to predict carbonate permeability and then compared with Winland permeability model. The research results demonstrate that the calculated fractal dimensions strongly depend on the fractal models used. Compared with the other three fractal models, 3D capillary tube model can effectively reflect the fractal characteristics of carbonate microscale and nanoscale pores. Fractal dimensions of microscale pores positively correlate with fractal dimensions of the entire carbonate pores, yet negatively correlate with fractal dimensions of nanoscale pores. Although nanoscale pores widely develop in carbonates, microscale pores have greater impact on the fractal characteristics of the entire pores. Fractal permeability model is applicable in predicting carbonate permeability, and compared with the Winland permeability model, its calculation errors are acceptable.

A Comparison of the Pore Structure of Cement and Fly Ash/Cement Mortars Made with Sea Water and Fresh Water

1986 ◽  
Vol 85 ◽  
Author(s):  
B. K. Marsh ◽  
R. C. Joshi ◽  
A. Balasundaram
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Fresh Water ◽  
Mercury Intrusion Porosimetry ◽  
Sea Water ◽  
Blended Cement ◽  
Fly Ashes ◽  
Mercury Intrusion ◽  
Pore Structures ◽  
Cement Mortars

ABSTRACTPore structures of portland and blended cement mortars prepared with sea water were assessed by mercury intrusion porosimetry. Comparison is made with similar mortars made with fresh water. Mortars were made using cement containing 0%, 25% or 50% (by volume) of one of two Alberta fly ashes. They were tested after 90 days of continuous immersion in sea water at 5°C or 20° C. Results show that the mortars made with sea water generally contained a much higher volume of fine pores although the porosity was, in some cases, greater than that of mortars made with fresh water. Nevertheless, the volume of larger pores was lower in the mortars made with sea water. The pore structure of the various mortars is discussed in relation to potential durability.

scholarly journals Use of Bioceramics Enhanced with Effective Microorganisms as an Additive for Construction. Study of Physical and Mechanical Properties in Cement Mortars and Gypsum Plasters

2021 ◽  
Vol 11 (8) ◽  
pp. 3519
Author(s):  
Filomena Pérez-Gálvez ◽  
María Jesús Morales-Conde ◽  
Manuel Alejandro Pedreño-Rojas
Keyword(s):  
Mechanical Properties ◽  
Mercury Intrusion Porosimetry ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Slight Improvement ◽  
Effective Microorganisms ◽  
Mercury Intrusion ◽  
Experimental Campaign ◽  
Cement Mortars ◽  
Scanning Electron

Biomaterials are materials that are used to manufacture devices that interact with biological systems. According to their chemical composition, they can be classified as biometals, biopolymers, bioceramics, biocomposites and semiconductors. Thus, in the present work, the application of bioceramics, enhanced with effective microorganisms, to construction materials (cement mortars and gypsum plasters) was studied in order to see the benefits that its incorporation contributes to construction materials. This first work constitutes the first phase of an experimental campaign in which the influence of bioceramics on the physical and mechanical properties (flexural and compressive strength) of the studied materials was analyzed. Furthermore, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) techniques were used. According to the results, a slight improvement in the mechanical properties of the new composites was observed. Besides, a more compact matrix was observed when bioceramics were used as an aggregate to the mixtures.

scholarly journals FRACTAL CHARACTERIZATION OF TIGHT OIL RESERVOIR PORE STRUCTURE USING NUCLEAR MAGNETIC RESONANCE AND MERCURY INTRUSION POROSIMETRY

Fractals ◽  
2018 ◽  
Vol 26 (02) ◽  
pp. 1840017 ◽  
Author(s):  
FUYONG WANG ◽  
KUN YANG ◽  
JIANCHAO CAI
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pore Structure ◽  
Pore Size ◽  
Mercury Intrusion Porosimetry ◽  
Fractal Dimensions ◽  
Structure Characterization ◽  
Tight Oil ◽  
Petrophysical Properties ◽  
Mercury Intrusion

Tight oil sandstones have the characteristics of narrow pore throats, complex pore structures and strong heterogeneities. Using nuclear magnetic resonance (NMR) and mercury intrusion porosimetry (MIP), this paper presents an advanced fractal analysis of the pore structures and petrophysical properties of the tight oil sandstones from Yanchang Formation, Ordos Basin of China. Firstly, nine typical tight oil sandstone core samples were selected to conduct NMR and MIP test for pore structure characterization. Next, with the pore size distribution derived from MIP, it was found that the relationships between NMR transverse relaxation time [Formula: see text] and pore size are more accordant with the power function relations, which were applied to derive pore size distribution from NMR rather than the linear relation. Moreover, fractal dimensions of micropores, mesopores and macropores were calculated from NMR [Formula: see text] spectrum. Finally, the relationships between the fractal dimensions of different size pores calculated from NMR [Formula: see text] spectrum and petrophysical properties of tight oil sandstones were analyzed. These studies demonstrate that the combination of NMR and MIP can improve the accuracy of pore structure characterization and fractal dimensions calculated from NMR [Formula: see text] spectrum are effective for petrophysical properties analysis.

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