Determination of Permeability Properties of Concrete Surface Modified by CPF

2015 ◽  
Vol 732 ◽  
pp. 389-392 ◽  
Author(s):  
Pavel Reiterman
Keyword(s):  
Surface Layer ◽  
Water Transport ◽  
Concrete Surface ◽  
Experimental Results ◽  
Experimental Program ◽  
Functional Characteristics ◽  
Concrete Permeability ◽  
Surface Modified ◽  
Durability Of Concrete

The paper introduces an experimental program focused on the monitoring of water transport in surface layer of concrete aimed at monitoring the permeability of concrete, since concrete permeability is a property uniquely affecting durability of concrete. Introduced methods are complemented by experimental results and other traditional tests. These findings will serve to further optimization of the structure being created, thus ensuring its better aesthetic and functional characteristics.

Permeability and Basic Physical Properties of Concrete with Metakaolin Addition

2013 ◽  
Vol 486 ◽  
pp. 313-318 ◽  
Author(s):  
Pavel Reiterman ◽  
Martin Keppert ◽  
Monika Čáchová ◽  
Ondřej Holčapek ◽  
Filip Vogel ◽  
...  
Keyword(s):  
Surface Layer ◽  
Physical Properties ◽  
Surface Resistance ◽  
External Environment ◽  
Concrete Surface ◽  
Experimental Program ◽  
Hardened Concrete ◽  
Porous System ◽  
Freeze Thaw ◽  
Concrete Permeability

Surfacing, concrete mixture composition and curing are of great importance for the concrete surface resistance. Thats the reason, why many leading experts agree on the importance of monitoring the concrete skin as the most loaded area affected by the external environment. Many research works demonstrate that application of metakaolin improves properties of concrete as freeze-thaw resistance and resistance against de-icing salts with freeze-thaw cycles combination. A very important role in concrete performance in such severe environment is played by porous system and surface of hardened concrete. The paper introduces an experimental program focused on the monitoring of water transport in surface layer of fair-face concrete aimed at monitoring the permeability of concrete, since concrete permeability is a property uniquely affecting durability of concrete. These methods are complemented by experimental results and other traditional tests. These findings will serve to further optimization of the structure being created, thus ensuring its better aesthetic and functional characteristics.

scholarly journals Effects of Anti-Graffiti Protection on Concrete Durability

2014 ◽  
Vol 634 ◽  
pp. 517-526 ◽  
Author(s):  
Elsa Neto ◽  
Ana Souto ◽  
Aires Camões ◽  
Arlindo Begonha ◽  
Paulo Cachim
Keyword(s):  
Water Absorption ◽  
Atmospheric Pressure ◽  
Surface Characteristics ◽  
Concrete Surface ◽  
Experimental Program ◽  
Concrete Durability ◽  
Protection Systems ◽  
Before And After ◽  
Paint Removal ◽  
Durability Of Concrete

The heritage of fair-faced concrete, largely built in the twentieth century and nowadays recognized as heritage to be protected, is susceptible to attacks by graffiti, a form of vandalism that causes a major social and economic impact on society. Concrete is a porous material sometimes deteriorated over the years, and the interactions between the inks and the substrate and removal methods sometimes deteriorate or alter the concrete surface, especially if it is necessary to repeat the removal process. The anti-graffiti products are applied on the surface of the concrete, hindering the adhesion of paints or preventing its penetration into the pores of concrete, which in turn facilitates their removal. However, it appears that many of the existing protective products on the market may also alter the surface characteristics of the concrete irreversibly. Considering that the durability of concrete depends on the composition and characteristics of the surface, it is essential to know the effects of anti-graffiti protection systems on the durability of concrete and adopt the appropriate methodology to preserve this heritage. Thus, an experimental program was developed for analyzing changes in durability indicators and surface properties that protect concrete from deterioration (i) concrete without protection before and after application of spray paint, (ii) concrete with protection before and after application of spray paint and (iii) after paint removal were studied. Two anti-graffiti products were evaluated: a permanent and a sacrificial one. Effects of the anti-graffiti systems on the concrete durability are investigated and the tests performed include: water absorption by capillary and immersion at atmospheric pressure. The results of the water absorption tests show that the graffiti protection reduces the water absorption into the concrete and facilitates the removal of the graffiti without affecting negatively the characteristics of the surface and thus contributing to improve its durability.

Experimental Determination of Concrete Resistance of Various Composition to Water and De-Icing Chemicals

2016 ◽  
Vol 714 ◽  
pp. 159-164 ◽  
Author(s):  
Dalibor Kocáb ◽  
Tereza Komárková ◽  
Monika Králíková ◽  
Petr Misák ◽  
Bronislava Moravcová
Keyword(s):  
Surface Layer ◽  
Strong Dependence ◽  
Concrete Surface ◽  
Test Methods ◽  
Test Surface ◽  
Concrete Durability ◽  
Cement Concrete ◽  
Freezing And Thawing ◽  
Surface Layer Quality

The focus of the project GAČR 13-18870S is the research in concrete durability determined primarily by its surface layer quality. The surface layer can be difficult to assess for which reason the project makes use of available standardised and non-standardised test methods by means of which the concrete surface layer or its internal structure can be examined. One of these methods which is commonly used is Determination of resistance of cement concrete surface to water and defrosting chemicals. The paper presents the results of experiments performed with concretes differing only in w/c ratio and plasticiser content. Two more methods were used during the research based on the action of a thawing solution upon the surface of the specimen during freezing and thawing. The only difference between these methods is the direction in which the thawing agent acts on the test surface. The presumed experiment outcome was the existence of a strong dependence of the outcomes of the methods on the w/c ratio. The performed analyses confirmed the experiment presumption.

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

Optimization of a Specimen Size for the Determination of the Diffusible Hydrogen Content in Metals

2014 ◽  
Vol 698 ◽  
pp. 466-471
Author(s):  
Oleg V. Panchenko ◽  
Alexey M. Levchenko ◽  
Victor A. Karkhin
Keyword(s):  
Hydrogen Content ◽  
Calculation Method ◽  
Specimen Size ◽  
Experimental Results ◽  
Diffusible Hydrogen ◽  
Measuring Methods ◽  
Deposited Metal ◽  
Calculation Results

Specimens of various sizes are used to determine hydrogen content in deposited metals in such standards as ISO 3690, AWS A 4.3, and GOST 23338 while measuring methods are the same. It causes problems in comparison of experimental results and brings up the following question: what kind of specimen size is optimal to determine hydrogen content? An optimal specimen size was estimated using a calculation method. Experimental and calculation results obtained by using specimens with estimated dimensions were compared to the results obtained by using the specimen with dimensions of 100*25*8 mm to determine hydrogen content in a deposited metal.

Spectroscopie par Source Laser. IV. Application de la Théorie d'Anderson au Calcul des Largeurs des Raies de la Transition 10°0–00°1 de N2O. Influence de l'Octupôle sur la Détermination du Moment Quadrupolaire de N2O

1973 ◽  
Vol 51 (6) ◽  
pp. 605-609 ◽  
Author(s):  
C. Boulet ◽  
N. Lacome ◽  
P. Isnard
Keyword(s):  
Quadrupole Moment ◽  
Experimental Results ◽  
Molecular Parameters ◽  
Line Widths

From the analysis of the available experimental results, a vibrational dependence of N2O line widths is shown, which can be explained, applying the Anderson–Tsao–Curnutte theory. But no dependence on ν of any of the molecular parameters can be deduced. In the last part, we have pointed out the effect on the determination of the quadrupole moment of assuming a nonvanishing octupole moment for N2O.

scholarly journals A Generalized Method for Flat Plates Impact Detection and Location

2013 ◽  
Vol 543 ◽  
pp. 171-175
Author(s):  
Jose Andrés Somolinos ◽  
Rafael Morales ◽  
Carlos Morón ◽  
Alfonso Garcia
Keyword(s):  
Signal Processing ◽  
Flat Plate ◽  
Acoustic Signal ◽  
Experimental Results ◽  
Piezoelectric Sensors ◽  
Experimental Setup ◽  
Flat Plates ◽  
Impact Detection ◽  
Timing Difference

In the last years, many analyses from acoustic signal processing have been used for different applications. In most cases, these sensor systems are based on the determination of times of flight for signals from every transducer. This paper presents a flat plate generalization method for impact detection and location over linear links or bars-based structures. The use of three piezoelectric sensors allow to achieve the position and impact time while the use of additional sensors lets cover a larger area of detection and avoid wrong timing difference measurements. An experimental setup and some experimental results are briefly presented.

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