scholarly journals Durability Assessment of Concrete by using Electrical Resistivity & Rapid Chloride Permeability Technique

2019 ◽  
Vol 9 (1) ◽  
pp. 5175-5179
Keyword(s):  
Electrical Resistivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Experimental Studies ◽  
Concrete Durability ◽  
Chloride Permeability ◽  
Distribution Shape ◽  
Porous Microstructure ◽  
Durability Of Concrete

The durability of concrete is generally evaluated by many NDT technique, among the different NDT technique RCPT is one of the popular NDT method used by many researchers & practicing Engineers for evaluation of concrete durability. However the RCPT technique has some limitation on field test of concrete, considering the limitation of the RCPT technique a new technique has been intr oduced called Electrical resistivity technique is used for evaluation of concrete durability in both field & lab test. Durability of concrete is mainly depends on the properties of concrete microstructure i.e. pore size distribution, shape & connectivity of the microstructural pores in concrete. In general smaller pore size, with lesser connectivity results lower permeability & shows more durability, while concrete with porous microstructure having larger pore size distribution along with larger degree of interconnections results in higher permeability and shows poor durability. In this paper an experimental studies were conducted for evaluation of concrete durability on different types of concrete samples by using electrical resistivity & RCPT technique. From the experimental results it has been observed that concrete with lower level of Chloride permeability shows higher Electrical resistivity. Thus Electrical resistivity of concrete is directly influencing the durability of concrete.

Error propagation in the estimation of glomerular pressure from macromolecule sieving data

1995 ◽  
Vol 268 (4) ◽  
pp. F736-F745 ◽  
Author(s):  
A. Edwards ◽  
W. M. Deen
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Experimental Studies ◽  
Systematic Errors ◽  
Published Data ◽  
Hydraulic Pressure ◽  
Random Errors ◽  
True Value ◽  
Experimental Errors

The theoretical effects of the glomerular transmural hydraulic pressure difference (delta P) on the sieving coefficients (theta i) of macromolecules of varying size have led to a number of attempts to use sieving curves to estimate delta P noninvasively, with inconsistent results. The objective of this study was to determine the extent to which experimental errors and imperfections in the theoretical models limit the ability to obtain reliable estimates of delta P using this method. Our approach was to generate many sets of synthetic “experimental data” using computer simulations of glomerular sieving and to compute values of delta P by fitting models to those data in the presence of various types and magnitudes of errors. Unbiased experimental errors were simulated by adding random amounts to individual values of theta i, and systematic errors were investigated by using a model based on one type of pore-size distribution to fit “data” generated using a model of a different type. We found that with random errors in theta i only, the estimate of delta P was accurate to within +/- 4 mmHg nearly all of the time, provided that the standard deviation, sigma i, was < or = 5% of theta i. When there were also systematic errors arising from the use of an “incorrect” form of pore-size distribution, a useful predictor of success was the probability P that the residuals, the differences between the measured and predicted sieving coefficients, were randomly distributed. A value of P > 0.2, as calculated from the algebraic signs of the residuals, indicated a high likelihood that the pressure estimate was accurate, provided that the random errors were sufficiently small. When P > 0.2, the fitted value of delta P was within +/- 4 mmHg of the true value in about 90%, 80%, and 70% of the cases examined when sigma i was < or = 2%, 5%, or 10% of theta i, respectively. An analysis of published data from a number of experimental studies indicated, however, that the favorable conditions of small sigma i and large P are extremely difficult to achieve, making it unlikely that an accurate group-mean value of delta P will be estimated from any given set of sieving data. Significant experimental and theoretical advances will be needed to make this a reliable method for estimating glomerular pressure.

The Comparison and Analysis of Pore Size Distribution between Cotton Yarn and Fabric

2011 ◽  
Vol 339 ◽  
pp. 676-679
Author(s):  
Jian Feng Di ◽  
Xiao Xia He ◽  
Wen Qin Du ◽  
Hong Jin Qi
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Distribution Shape ◽  
Ratio Data ◽  
Order Of Magnitude ◽  
Comparison And Analysis ◽  
Wall Interaction ◽  
As Relationship ◽  
Liquid Movement

To obtain more detailed and accurate pore size distribution for cotton fabric, this paper focuses on comparing size distribution between the yarn and fabric. The result shows that there are great difference as well as relationship in size distribution between the yarn and fabric. The size in fabric has 2 orders of magnitude including that in yarn with just 1 order of magnitude. The pore size ratio data also illustrate that the pore in yarn account for 33.3% of that in fabric, suggesting that the pore in yarn has a certain impact on the wicking behavior of fabric. However, the graphic exhibit that the size distribution shape in yarn is different from that in fabric, which may be owing to the fabric weaving configuration, implying that wicking liquid movement is affected not just by capillary effect along the yarn but also by interlacing points and fluid-wall interaction in the complex channels of fabric.

Chloride Permeability Of Concrete Containing A Flyash And A Blastfurnace Slag

1988 ◽  
Vol 137 ◽  
Author(s):  
Mitsunori Kawamura ◽  
Kazuyuki Torii
Keyword(s):  
Portland Cement ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mercury Intrusion Porosimetry ◽  
Chloride Permeability ◽  
Curing Conditions ◽  
Mercury Intrusion ◽  
Blastfurnace Slag ◽  
Low Humidity

AbstractThe effects of curing conditions on the chloride permeability of concrete with various replacements of Portland cement by a flyash and a blastfurnace slag was investigated. In order to relate the porosity and pore size distribution of concretes to their chloride permeability, mercury intrusion porosimetry measurements were also conducted. The results showed that exposure of concretes to a relatively low humidity at early ages increased their chloride permeability. It was also found that the chloride permeability of concrete increased proportionally with increasing volume of pores larger than 0.1 μm in diameter.

scholarly journals Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ludovica Casnedi ◽  
Ombretta Cocco ◽  
Paola Meloni ◽  
Giorgio Pia
Keyword(s):  
Pore Size Distribution ◽  
Water Absorption ◽  
Pore Size ◽  
Size Distribution ◽  
Cement Pastes ◽  
Water Absorption Coefficient ◽  
Proposed Model ◽  
Porous Microstructure ◽  
Base Units ◽  
Good Agreement

An intermingled fractal units’ model is shown in order to simulate pore microstructures as pore fraction and pore size distribution. This model is aimed at predicting capillary water absorption coefficient and sorptivity values in cement pastes. The results obtained are in good agreement with the experimental ones. For validating this model, a comparison with other procedures has been shown. It is possible to establish that the newly proposed method matches better with the experimental results. That is probably due to the fact that pore size distribution has been considered as a whole. Moreover, even though the proposed model is based on fractal base units, it is able to simulate and predict different properties as well as nonfractal porous microstructure.

pyGAPS: A Python-Based Framework for Adsorption Isotherm Processing and Material Characterisation

2019 ◽  
Author(s):  
Paul Iacomi ◽  
Philip L. Llewellyn
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
Isosteric Heat ◽  
Material Characterisation ◽  
Mixture Adsorption ◽  
Surface Energetics ◽  
Adsorption Processing ◽  
User Friendly

Material characterisation through adsorption is a widely-used laboratory technique. The isotherms obtained through volumetric or gravimetric experiments impart insight through their features but can also be analysed to determine material characteristics such as specific surface area, pore size distribution, surface energetics, or used for predicting mixture adsorption. The pyGAPS (python General Adsorption Processing Suite) framework was developed to address the need for high-throughput processing of such adsorption data, independent of the origin, while also being capable of presenting individual results in a user-friendly manner. It contains many common characterisation methods such as: BET and Langmuir surface area, t and α plots, pore size distribution calculations (BJH, Dollimore-Heal, Horvath-Kawazoe, DFT/NLDFT kernel fitting), isosteric heat calculations, IAST calculations, isotherm modelling and more, as well as the ability to import and store data from Excel, CSV, JSON and sqlite databases. In this work, a description of the capabilities of pyGAPS is presented. The code is then be used in two case studies: a routine characterisation of a UiO-66(Zr) sample and in the processing of an adsorption dataset of a commercial carbon (Takeda 5A) for applications in gas separation.

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