This document summarizes research on using ultrasonic pulse velocity (UPV) testing to evaluate concrete properties non-destructively. The researchers measured the UPV and compressive strength of concrete cubes with varying water-cement ratios between 0.35 and 0.7 at ages of 2, 7, 15, and 28 days. They found that both UPV and compressive strength increased with age, but the rate of increase depended on the water-cement ratio. A relationship curve was developed between UPV and compressive strength for concretes with different water-cement ratios, showing that UPV can be used to estimate compressive strength non-destructively.
Dislocation and twin substructure evolution during strain hardening of an Fe–22 wt.% Mn–0.6 wt.% C TWIP steel observed by electron channeling contrast imaging
functionalized multi walled carbon nanotube-reinforced epoxy-composites elec...INFOGAIN PUBLICATION
Carbon nanotubes (CNTs) got great attention because of their interesting physical and mechanical properties. Due to these interesting properties observed at the nanoscale have motivated scientific community to utilize CNTs as reinforcement in composite materials. In the present study, different CNTs and epoxy nano-composites with different wt% (1, 2, 3, and 4%) of f-MWCNTs were prepared and their surface morphology and orientation has been investigated in detail. Further, the surface investigation, electrical and mechanical tests were carried out on CNTs-filled and unfilled epoxy at maximum sonication time 30 minute to identify the loading effect on the properties of the materials. Experimental results depicts well dispersion of f-MWCNTs, significant improvement that the resistivity of pure epoxy decreased from 108 .m to average value 103 .m with 1, 2, 3, and 4wt% f-MWCNTs. The 4.5wt% CNTs/epoxy was attributed to poor dispersion of f-MWCNTs in the nanocomposte. The hardness of nanocomposite loading 1, 2, 3, 4wt% of CNTs, increased 20.7%, 23.02%, 25.62%, 29.09% respectively as compared to pure epoxy. We believe that our strategy for obtaining CNT–reinforced epoxy nanocomposites is a very promising technology and will open a new doors in fields of aviation, aerospace, marine and sporting goods.
This paper involves an experimental investigation on the flexural behaviour of curved beams and comparison of its results with conventional beams. Curved beams of size 1200 x 150 x 100 mm with varying initial curvature as 4000mm, 2000mm and the concrete strength as M40 is considered. Various reinforcement are provided in the curved beams to predict which reinforcement detail would give more resistant over maximum loading. The material properties of cement, fine aggregate, coarse aggregate and the compressive strength of concrete cube were found out. A total of 12 specimens of curved beams were casted with various combination of reinforcement along with three control specimens. The beams are tested under two point loading both horizontally and vertically. The deflection and maximum moment carrying capacity are investigated to understand its strength. Also analytical modelling is done to determine the ultimate moment carrying capacity using Finite Element Software ABAQUS to compare with the experimental model.
Dislocation and twin substructure evolution during strain hardening of an Fe–22 wt.% Mn–0.6 wt.% C TWIP steel observed by electron channeling contrast imaging
functionalized multi walled carbon nanotube-reinforced epoxy-composites elec...INFOGAIN PUBLICATION
Carbon nanotubes (CNTs) got great attention because of their interesting physical and mechanical properties. Due to these interesting properties observed at the nanoscale have motivated scientific community to utilize CNTs as reinforcement in composite materials. In the present study, different CNTs and epoxy nano-composites with different wt% (1, 2, 3, and 4%) of f-MWCNTs were prepared and their surface morphology and orientation has been investigated in detail. Further, the surface investigation, electrical and mechanical tests were carried out on CNTs-filled and unfilled epoxy at maximum sonication time 30 minute to identify the loading effect on the properties of the materials. Experimental results depicts well dispersion of f-MWCNTs, significant improvement that the resistivity of pure epoxy decreased from 108 .m to average value 103 .m with 1, 2, 3, and 4wt% f-MWCNTs. The 4.5wt% CNTs/epoxy was attributed to poor dispersion of f-MWCNTs in the nanocomposte. The hardness of nanocomposite loading 1, 2, 3, 4wt% of CNTs, increased 20.7%, 23.02%, 25.62%, 29.09% respectively as compared to pure epoxy. We believe that our strategy for obtaining CNT–reinforced epoxy nanocomposites is a very promising technology and will open a new doors in fields of aviation, aerospace, marine and sporting goods.
This paper involves an experimental investigation on the flexural behaviour of curved beams and comparison of its results with conventional beams. Curved beams of size 1200 x 150 x 100 mm with varying initial curvature as 4000mm, 2000mm and the concrete strength as M40 is considered. Various reinforcement are provided in the curved beams to predict which reinforcement detail would give more resistant over maximum loading. The material properties of cement, fine aggregate, coarse aggregate and the compressive strength of concrete cube were found out. A total of 12 specimens of curved beams were casted with various combination of reinforcement along with three control specimens. The beams are tested under two point loading both horizontally and vertically. The deflection and maximum moment carrying capacity are investigated to understand its strength. Also analytical modelling is done to determine the ultimate moment carrying capacity using Finite Element Software ABAQUS to compare with the experimental model.
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
STUDY ON EFFECTIVE THERMAL CONDUCTIVITY OF COPPER PARTICLE FILLED POLYMER COM...Study Hub
Guarded heat flow meter test method is used to measure the thermal conductivity of Copper powder filled epoxy composites using an instrument UnithermTM Model 2022 in accordance with ASTM-E1530. In the numerical study, the finite-element package ANSYS is used to calculate the conductivity of the composites. Three-dimensional spheres-in-cube lattice array models are used to simulate the microstructure of composite materials for various filler concentrations. This study reveals that the incorporation of copper particulates results in enhancement of thermal conductivity of epoxy resin and thereby improves its heat transfer capability. The experimentally measured conductivity values are compared with the numerically calculated ones and it is found that the values obtained for various composite models using finite element method (FEM) are in reasonable agreement with the experimental values.
Investigation of the Effects of Fullerene addition and Plasma Exposure on Opt...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Effect of stacking sequence and hybridization on the tensile and flexural properties of composite
laminates between basalt, jute and flax with E-glass reinforced epoxy have been investigated experimentally. It
was found that stacking sequence is not highly significant on tensile properties, contrasting with flexural strength
and modulus which were strongly dependent on the hybrid configuration between sandwich-like (SL) and
intercalation (IC) sequences. Specific modulus based on the variation densities of the hybrid laminates was used
to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning
on the strength to weight- ratio. Hence, stacking sequences and material selection are among predominant factors
that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired
requirements.
An Image Analysis Technique to Estimate the Porosity of Rock SamplesIJSRD
This paper discusses the possibilities of determining the porosities of different types of rocks using image analysis technique. Before the use of image analysis stereological research for analysis of porosity were conducted by traditional methods which were time consuming and lacked accuracy. The method proposed in this paper determines the porosity by computing the part of the whole sample for which the pores account. The steps involved in the above method are a series of contextual, non-context and morphological operations that are commonly used in image processing and analysis. The procedure was tested on thin sections of sandstone and limestone rock samples. The results were computed in the form of total porosity which includes all types porosities observed in rocks including isolated and connected porosities. The porosity obtained can also be called as visual porosity. Values obtained show that the method proposed can lead to satisfying results. Obtained porosity values can be used further to determine determine other properties like permeability which play a vital role in the study of diffusion in porous rocks.
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
STUDY ON EFFECTIVE THERMAL CONDUCTIVITY OF COPPER PARTICLE FILLED POLYMER COM...Study Hub
Guarded heat flow meter test method is used to measure the thermal conductivity of Copper powder filled epoxy composites using an instrument UnithermTM Model 2022 in accordance with ASTM-E1530. In the numerical study, the finite-element package ANSYS is used to calculate the conductivity of the composites. Three-dimensional spheres-in-cube lattice array models are used to simulate the microstructure of composite materials for various filler concentrations. This study reveals that the incorporation of copper particulates results in enhancement of thermal conductivity of epoxy resin and thereby improves its heat transfer capability. The experimentally measured conductivity values are compared with the numerically calculated ones and it is found that the values obtained for various composite models using finite element method (FEM) are in reasonable agreement with the experimental values.
Investigation of the Effects of Fullerene addition and Plasma Exposure on Opt...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Effect of stacking sequence and hybridization on the tensile and flexural properties of composite
laminates between basalt, jute and flax with E-glass reinforced epoxy have been investigated experimentally. It
was found that stacking sequence is not highly significant on tensile properties, contrasting with flexural strength
and modulus which were strongly dependent on the hybrid configuration between sandwich-like (SL) and
intercalation (IC) sequences. Specific modulus based on the variation densities of the hybrid laminates was used
to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning
on the strength to weight- ratio. Hence, stacking sequences and material selection are among predominant factors
that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired
requirements.
An Image Analysis Technique to Estimate the Porosity of Rock SamplesIJSRD
This paper discusses the possibilities of determining the porosities of different types of rocks using image analysis technique. Before the use of image analysis stereological research for analysis of porosity were conducted by traditional methods which were time consuming and lacked accuracy. The method proposed in this paper determines the porosity by computing the part of the whole sample for which the pores account. The steps involved in the above method are a series of contextual, non-context and morphological operations that are commonly used in image processing and analysis. The procedure was tested on thin sections of sandstone and limestone rock samples. The results were computed in the form of total porosity which includes all types porosities observed in rocks including isolated and connected porosities. The porosity obtained can also be called as visual porosity. Values obtained show that the method proposed can lead to satisfying results. Obtained porosity values can be used further to determine determine other properties like permeability which play a vital role in the study of diffusion in porous rocks.
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International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Mix design and mechanical properties of self compacting light weight concreteYahaya Hassan Labaran
A presentation based on a research paper review assignment
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2. Res. J. Appl. Sci. Eng. Technol., 3(6): 499-504, 2011
Fig. 1: Ultrasonic pulse velocity testing
Fig. 2: The PUNDIT plus set
enable certain properties of concrete to be measured in- types of elastic wave propagation. The fastest of these
situ, from which concrete strength is estimated, have been waves has particle displacements in the direction of travel
devised. Of the non-destructive techniques, the ultrasonic of the disturbance and is called the longitudinal,
pulse velocity technique offers the lowest cost of use and compression or P-wave. The compression wave velocity
is convenient as well as rapid to employ. Vp is a function of the dynamic Young’s modulus E, the
Poisson’s ratio L, and the mass density D, (Krautkramer
MATERIALS AND METHODS and Krautkramer, 1969; Marsh, 2000), and is given by:
Ultrasonic pulse velocity: When the surface of a semi-
E (1 − v )
infinite solid is excited by a time varying mechanical Vp =
force, energy is radiated from the source as three distinct ρ(1 + v )(1 − 2v )
500
3. Res. J. Appl. Sci. Eng. Technol., 3(6): 499-504, 2011
Table 1: Quality of concrete given by IS code (BS, 1881, 1983) as a
function of UPV 4700
UPV(m/s) Concrete quality 4500
Above 4500 Excellent
Av. Velocity (m/s)
3500 to 4500 Good 4300
3000 to 3500 Medium
Below 3000 Doubtful 4100
0.35
3900 0.40
It is clear from the above equation that velocity is 0.50
3700 0.60
independent of geometry of material and depends only on
0.75
elastic properties of the material through which it passes. 3500
0 5 10 15 20 25 30
Hence the principle of assessing quality of concrete is that Age (days)
comparatively higher velocities are obtained when the
quality of concrete in terms of density, homogeneity and Fig. 3: UPV of concrete cubes against age
uniformity is good. In case of poorer quality, lower
velocities are obtained (Table 1). concrete, receiving and amplifying the pulse and
In the test described in BS (1881): Part 203 (BS, measuring and displaying the time taken.
1881, 1986), the time the pulses take to travel through Materials used for making specimen include ordinary
concrete is recorded. Then, the velocity is calculated as: Portland Limestone type 2.5N, standard sand, Coarse
Aggregate (CA) of 10 mm grain size and water.
V= L/T (2) The water-cement ratio (w/c) used in this study
ranges from 0.35 to 0.75. The cement paste occupies
where V = pulse velocity (m/s), L = length (m), and T = approximately 18% of the total concrete volume.
effective time (s), which is the measured time minus the Five concrete specimens were produced for each
zero time correction. The zero time correction is equal to mixture proportion. All the specimens were cast in steel
the travel time between the transmitting and receiving moulds and kept in their moulds for approximately 24 h
transducers when they are pressed firmly together. in the laboratory. After removing the moulds, three
concrete cubes were tested at an age of 2 days and all
The UPV results can be used: other concrete cubes were cured in water at 20oC (68oF)
C To check the uniformity of concrete
and tested at ages 7, 15 and 28 days, respectively. At each
C To detect cracking and voids in concrete
age, the pulse velocity and compressive strength of the
C To control the quality of concrete and concrete
five specimens were measured according to the
products by comparing results to a similar made
specification of the British standard (Qasrawi, 2003). Five
concrete
simulation curves of the relationship between UPV and
C To detect the condition and deterioration of concrete
C To detect the depth of a surface crack compressive strength of hardened concrete are proposed
C To determine the strength if previous data are for concrete with w/c of 0.35, 0.4, 0.5, 0.6 and 0.75.
available These curves were verified to be suitable for prediction of
hardened concrete strength with a measured UPV value.
Since strength is the major property in structural concrete,
measured velocity was related to strength, and plots of RESULTS AND DISCUSSION
velocity vs. strength were obtained.
Figures 3 and 4 shows the UPV and strength
Experiments: The experimental set-up is shown development, respectively, with the age of concrete
schematically in Fig. 1. The apparatus (Fig. 2) which is having different w/c. Both the UPV and strength of
manufactured by CNS Farnell, London, derives its name concrete increase with the advancement of age. At the
from the initial letters of the full title of “Portable same age, both UPV and strength of concrete with low
Ultrasonic Non-Destructive Digital Indicating Tester” w/c are higher than those with high w/c as shown in
(PUNDIT). The dimensions of the unit are 185 mm × 130 Fig. 3 and 4 mainly because of the denser structure of
mm × 185 mm, and it weighs in at 3 kg. The ambient concrete with lower w/c.
temperature range to which the equipment may be Figure 3 indicates that concrete with high w/c (w/c =
operated is 0 to 45ºC. The test equipment provides a 0.75) at the age of 2 days has a UPV of about 89% of that
means of generating a pulse, transmitting this to the of 28 days, but the strength is only about 60%. Figure 3
501
4. Res. J. Appl. Sci. Eng. Technol., 3(6): 499-504, 2011
40.00 25.00
Compressive strength (Mpa)
Av. Compressive strength (Mpa)
35.00
20.00
30.00
25.00
15.00
20.00
0.35
15.00
0.40 10.00
10.00 0.50
5.00 0.60
5.00
0.75
0.00
0 5 10 15 20 25 30
0.00
Age (days) 4000.00 4400.00 4500.00
3900.00 4100.00 4200.00 4300.00
Av. Velocity (m/s)
Fig. 4: Compressive strength of concrete cubes against age
Fig. 7: Comparison of Av. Velocity and compressive strength
35.00 with 0.50 w/c
Av. Comprassive strength (MPa)
30.00 25
25.00
Compressive strength (Mpa)
20.00 20
15.00
15
10.00
5.00 10
0.00
4350.00 4400.00 4450.00 4500.00 4550.00
5
Av. Velocity (m/s)
Fig. 5: Comparison of Av. Velocity and compressive strength 0
with 0.35 w/c 3600.00 3800.00 4000.00 4200.00 4400.00
Av. Velocity (m/s)
40
Fig. 8: Comparison of Av. Velocity and compressive strength
35
Compressive strength (Mpa)
with 0.60 w/c
30
18.00
Av. Compressive strength (Mpa)
25 16.00
14.00
20
12.00
15 10.00
8.00
10
6.00
5 4.00
2.00
0
0.00
00 0 0
.0
0
0
0
0
. .0 .0 3600.00 3700.00 3800.00 3900.00 4000.00 4100.00 4200.00
.0
.0
.0
00 00 00 00
00
00
00
Av. Velocity (m/s)
41 42 43 44
45
46
47
Velocity (m/s)
Fig. 9: Comparison of Av. Velocity and compressive strength
with 0.75 w/c
Fig. 6: Comparison of Av. Velocity and compressive strength
with 0.40 w/c concrete becomes unclear when age and mixture
proportion is taken into consideration simultaneously.
also indicates that at the age of 2 days, concrete with low This observation suggests that it is be better to separately
w/c (w/c = 0.35) has a UPV that is approximately 97% of consider the effect of age and mixture proportion on UPV
that at 28 days and the strength is about 30%. To sum up, and strength relationship. For the given mixture
the UPV and strength growth rates of high and low w/c proportion, Figure 5 to 9 are used to acquire the UPV and
concrete are significantly different at an early age. As a strength values of hardened concrete having w/c of 0.35,
result, the relationship between UPV and strength of 0.40, 0.50, 0.60, 0.75.
502
5. Res. J. Appl. Sci. Eng. Technol., 3(6): 499-504, 2011
Table 2:Concrete mix proportion for verification of UPV-strength recommended ±10% deviation from the true value. This
relationship curves
verifies the suitability of the proposed relationship curves
w/c Cement/kg Sand/kg C.A (10 mm)/kg Water/L
0.35 15.4 30.9 61.7 4.6 for prediction of hardened concrete strength with a
0.40 15.4 30.9 61.7 6.2 measured UPV value.
0.50 15.4 30.9 61.7 7.7
0.60 15.4 30.9 61.7 9.2
CONCLUSION
0.75 15.4 30.9 61.7 11.6
Table 3: Comparison results of UPV-strength relationship The main objective of this paper is to investigate the
Theoretical Experimental relationship between the Ultrasonic Pulse Velocity (UPV)
w/c Av.velocity/ms C.S/MPa C.S/MPa and compressive strength of concrete as well as to
0.35 4755.00 33.15 32.25 understand the influence of the mixture proportion and the
0.40 7505.60 40.30 41.00
0.50 6305.00 29.00 30.40 age of concrete on the relationship between UPV and
0.60 5446.60 22.50 21.40 compressive strength. Specific conclusions are as follows:
0.75 4529.20 19.00 20.65
C The UPV and strength growth rates of high and low
In this study, five curves of the relationship between w/c concrete have a significant difference at an early
UPV and compressive strength are drawn for concrete age. As a result, to clearly define the relationship
with the given w/c. between UPV and the strength of concrete with
The equations for the curves of these five w/c are as different mixture proportions, it is necessary to
follows: eliminate the interference caused by the different
UPV and strength growth rates of concrete at early
F (0.35) = 1E-15 e0.008v (3) ages.
F (0.40) = 0.022 e0.001v (4) C The equations obtained from the simulation curves
F (0.50) = 0.053 e0.001v (5) can be used to determine the concrete strengths of the
F (0.60) = 0.097 e0.001v (6) concrete mix proportions.
F (0.70) = 0.205 e0.001v (7)
ACKNOWLEDGMENT
where F and v represent the compressive strength (MPa)
and the ultrasonic pulse velocity (m/s), respectively. For We offer our sincere gratitude to W. Nimako and
the five w/c (0.35, 0.40, 0.50, 0.60 and 0.75) the F. Mudey of the Engineering department of the Ghana
relationship between UPV and strength of concrete is Standards Board for their help, input and commitment.
pretty good for this particular mixture proportion with a We extend our thanks to all our colleagues at the Nuclear
very high coefficient of determination, R2 of 0.866, 0.981, Applications Centre, National Nuclear Research Institute,
0.888, 0.994 and 0.989, respectively. This indicates Ghana Atomic Energy Commission.
relevance between data points and the regression curves.
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