Experimental Study of Concrete Subjected to Explosive Loading
The main subject of this paper was to demonstrate the response of structural concrete to different imposed strain rates. Attention is focused on the strain rate about 10^-2 s^-1, where some technical difficulties are experienced when an exact determination of mechanical properties for quasi-brittle...
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Інститут проблем міцності ім. Г.С. Писаренко НАН України
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| Cite this: | Experimental Study of Concrete Subjected to Explosive Loading / R. Rekucki, L. Kruszka // Проблемы прочности. — 2002. — № 3. — С. 49-54. — Бібліогр.: 3 назв. — англ. |
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Rekucki, R. Kruszka, L. 2013-07-06T15:59:27Z 2013-07-06T15:59:27Z 2002 Experimental Study of Concrete Subjected to Explosive Loading / R. Rekucki, L. Kruszka // Проблемы прочности. — 2002. — № 3. — С. 49-54. — Бібліогр.: 3 назв. — англ. 0556-171X https://nasplib.isofts.kiev.ua/handle/123456789/46761 539.4 The main subject of this paper was to demonstrate the response of structural concrete to different imposed strain rates. Attention is focused on the strain rate about 10^-2 s^-1, where some technical difficulties are experienced when an exact determination of mechanical properties for quasi-brittle materials is attempted. The design of a measurement system, which realizes computer acquisition, analysis and graphics pictures viewing of date, is also presented. Выполненные экспериментальные исследования свидетельствуют о влиянии различных скоростей деформирования на прочность конструкционного бетона. Особое внимание уделено скорости деформирования 10^-2 с^-1 для которой проблематично точно определить механические характеристики квазихрупких материалов. Приведена новая конструкция системы измерения, в которой реализуются компьютеризованное получение, обработка и графическое представление экспериментальных данных. Проведені експериментальні дослідження свідчать про вплив різної швидкості деформування на міцність конструкційного бетону. Особлива увага зосереджена на швидкості деформування 10^-2 c^-1 , для якої проблематично точно визначити механічні характеристики квазікрихких матеріалів. Наведено нову конструкцію системи вимірювання, в якій реалізуються комп’ютеризоване одержання експериментальних даних, їхня обробка та графічне зображення. This paper was prepared within the framework of the research project No. 0T 00A 017 15 financed by the State Committee for Scientific Research (Poland). en Інститут проблем міцності ім. Г.С. Писаренко НАН України Проблемы прочности Научно-технический раздел Experimental Study of Concrete Subjected to Explosive Loading Экспериментальное исследование бетона при нагружении взрывом Article published earlier |
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Experimental Study of Concrete Subjected to Explosive Loading |
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Experimental Study of Concrete Subjected to Explosive Loading Rekucki, R. Kruszka, L. Научно-технический раздел |
| title_short |
Experimental Study of Concrete Subjected to Explosive Loading |
| title_full |
Experimental Study of Concrete Subjected to Explosive Loading |
| title_fullStr |
Experimental Study of Concrete Subjected to Explosive Loading |
| title_full_unstemmed |
Experimental Study of Concrete Subjected to Explosive Loading |
| title_sort |
experimental study of concrete subjected to explosive loading |
| author |
Rekucki, R. Kruszka, L. |
| author_facet |
Rekucki, R. Kruszka, L. |
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Научно-технический раздел |
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Научно-технический раздел |
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2002 |
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English |
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Проблемы прочности |
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Інститут проблем міцності ім. Г.С. Писаренко НАН України |
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Article |
| title_alt |
Экспериментальное исследование бетона при нагружении взрывом |
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The main subject of this paper was to demonstrate the response of structural concrete to different imposed strain rates. Attention is focused on the strain rate about 10^-2 s^-1, where some technical difficulties are experienced when an exact determination of mechanical properties for quasi-brittle materials is attempted. The design of a measurement system, which realizes computer acquisition, analysis and graphics pictures viewing of date, is also presented.
Выполненные экспериментальные исследования свидетельствуют о влиянии различных скоростей деформирования на прочность конструкционного бетона. Особое внимание уделено скорости деформирования 10^-2 с^-1 для которой проблематично точно определить механические характеристики квазихрупких материалов. Приведена новая конструкция системы измерения, в которой реализуются компьютеризованное получение, обработка и графическое представление экспериментальных данных.
Проведені експериментальні дослідження свідчать про вплив різної швидкості деформування на міцність конструкційного бетону. Особлива увага зосереджена на швидкості деформування 10^-2 c^-1 , для якої проблематично точно визначити механічні характеристики квазікрихких матеріалів. Наведено нову конструкцію системи вимірювання, в якій реалізуються комп’ютеризоване одержання експериментальних даних, їхня обробка та графічне зображення.
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| issn |
0556-171X |
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https://nasplib.isofts.kiev.ua/handle/123456789/46761 |
| citation_txt |
Experimental Study of Concrete Subjected to Explosive Loading / R. Rekucki, L. Kruszka // Проблемы прочности. — 2002. — № 3. — С. 49-54. — Бібліогр.: 3 назв. — англ. |
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2025-11-26T23:23:26Z |
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2025-11-26T23:23:26Z |
| _version_ |
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| fulltext |
UDC 539.4
Experimental Study of Concrete Subjected to Explosive Loading
R. Rekucki and L. Kruszka
Military University of Technology, Warsaw, Poland
УДК 539.4
Экспериментальное исследование бетона при нагружении
взрывом
Р. Рекуцки, Л. Крушка
Военно-техническая академия, Варшава, Польша
Выполненные экспериментальные исследования свидетельствуют о влиянии различных ско
ростей деформирования на прочность конструкционного бетона. Особое внимание уделено
скорости деформирования 10~2 с д л я которой проблематично точно определить меха
нические характеристики квазихрупких материалов. Приведена новая конструкция системы
измерения, в которой реализуются компьютеризованное получение, обработка и графичекое
представление экспериментальных данных.
Ключевые слова: динамические исследования, нагружение взрывом, конст
рукционный бетон.
Introduction. Intensive development of the theories describing the behavior
under dynamic loading conditions of brittle materials (concretes and rocks)
requires experimental verification of these theories. Models of these construction
materials, especially in the domain of short-term loads, are not comprehensive
unless they are experimentally verified. At present, the experimental techniques
for testing of brittle materials, based among others, on the Hopkinson bar method,
or those with the use of explosive materials [1] have been developed.
Recently an enhanced development of measurement methods enabling the
improved precision in the determination of physical values has been observed.
Digital systems of large processing capacities and those of analyzing
measurement signals became principal measurement systems. This technology,
however, requires costly and precise data sources, the so-called “measurement
sensors.”
In the domain of fortification structures, concrete-and-steel reinforced
concrete objects are in the most cases kept deep under the ground and during their
service can be subjected to the pressure wave loads. Concretes used for the
construction, besides their static testing, require verification of their strength
under pulse loading of parameters approximating the operational ones. Modern
measurement converters and loading stands, working in support on loads
generated as a result of rapid burning of powders make it possible to answer those
requirements, too.
© R. REKUCKI, L. KRUSZKA, 2002
ISSN 0556-171X. Проблемы прочности, 2002, N 3 49
R. Rekucki and L. Kruszka
Characteristics of Loads Used in the Dynamic Tests. A pressure wave
load of variable increasing time, up to its maximal value and of duration
depending on powder grain diameter is obtained while using nitrocellulose
powders of various grain gradients for combustion in a generator of a specially
designed loading stand, characteristics of which have been presented in [3] (see
Fig. 1).
Fig. 1. Schem e o f the experim ental set-up fo r dynam ic tests o f structural m aterials: 1 - dynam ic
loading generator, 2 - steel colum ns, 3 - low er foundation plate, 4 - low er sliding plate, 5 - top
sliding plate, 6 - fixed plate, 7 - investigated specim en, 8 - hydraulic servo.
The time of the load increase to its maximal value was 24.6 ms, while the
loading duration did not exceed 50 ms. During the experiment, the specimen did
not break, but distinct cracks could be seen on its surfaces.
In further fracturing testing aimed at the determination of structural concrete
strength in compression, only the rising branch of the pressure wave is used for
determination of the value of fracturing force. On the other hand, it is controlled
by the amount of powder of the given grain gradient, portioned in to the generator
combustion chamber.
Measurement System. Determination of the strength of structural concrete
in compression under dynamic loading by pressure wave and the development of
the stress-strain relationship diagram were adopted as the main goal of this study.
Experiments were conducted on standard cubic specimens (150x150x150 mm).
Measurement of stresses was carried out directly by recording the liquid pressure
variation in the hydraulic operator (measurement in point 1, Fig. 2). Cubic
concrete specimen was placed between the two steel interface liners of hardened
surfaces, each being 10 mm thick. Contact surfaces were covered with oil. Such
procedure made it possible to partially eliminate the shear stresses occurring at
the specimen/plates contact zone. The EA-06-10CBE-120 foil resistance strain
gauges of 30 mm measurement base and 120 Q resistance were glued on the
surface of the specimen under study and used for measurement of the concrete
strain.
50 ISSN 0556-171X. npo6n.eubi npounocmu, 2002, N 3
Experimental Study o f Concrete
During the experiment, vertical £ strains (point 4) and the horizontal ones
(point 5) were measured by connecting the strain gauges to the full bridge system
(Fig. 2) with two compensation strain gauges balancing the effect of temperature.
Strain gauges were glued on the opposite walls of the cubic specimen. The
recording of global deformation of the tested specimen along with the slide of the
upper sliding plate were carried out with a transformer differential displacement
sensor by placing it at the point 2. Taking into account the sensor possible
damage, the plate sliding distance was limited to 6 mm. Moreover, the slide
velocity of the plate V-point 3 and vibrations in measurement points 6 and 7 were
registered. All values were registered by an indirect method as electric potential
changes in the function of time, corresponding to the changes in the individual
parameters of physical values. In order to determine the static strength, six
specimens from each series were subjected to static tests carried out at the
standardized velocity of load increase: 0.2-0.3 MPa/s. Static tests were made on a
hydraulic press with the ability to generate forces up to 1500 kN.
Fig. 2. D istribution o f m easurem ent points on the testing stand.
Computerized Measurement System. Each investigated physical value was
recorded on separate measurement tracks, realizing the feeding of measurement
sensors and processing the input signals from the sensors into the og output
signals of 0.5-10 V. All bridges and amplifiers had a transmission band of
0-20 kHz which enabled recording of rapid variability processes. As far as all
recorded signals are in the analog form and there is no possibility of clear
determination of the time interval starting, from the moment of the feeding source
switch-on till the ignition of the powder charge, a measurement tape-recorder has
been chosen as a recording tool.
ISSN 0556-171X. npo6n.eubi npounocmu, 2002, № 3 51
R. Rekucki and L. Kruszka
In this case, it is the 8-channel recorder of the Racal company. This recording
unit enables a simultaneous recording of runs of eight analog values on a VHS
tape of enhanced magnetic properties. The recording is realized in a FM
modulation mode in the 0-100 kHz band. At the output, the analog signal of 1 V
amplitude is obtained, which is then subjected to sampling and encoding by the
DAS-16F analog-to-digital converter. Further analysis in the domain of time and
frequency and appropriate processing is conducted with the use of computer
systems or special analyzers (e.g., spectral ones) and the ASYST software.
Results. Twenty specimens of structural concrete of the B30 class of component ratio w (water) : c (cement) : k (aggregate) - 1 : 1.12 : 11.76, on the
Polish Portland cement basis were prepared for testing.
All-in aggregate of a 0.5-8 mm thickness fraction was used as a concrete
aggregate. Static and dynamic strength tests were carried out with the average
load velocity of 0.14 MPa/s corresponding to the average deformation rate
of 52 m̂/s. For the investigated specimen series, the average compression
strength of the concrete was Rc = 30.88 MPa. The maximal increase of local
vertical deformations in the analyzed specimen series was £ = 1280 m̂/m. The
average time of the load increase up to the fracture was 230 s.
The dynamic testing in the case of the series discussed was conducted only at
one velocity of the load increase, equaling on the average to 1505 MPa/s
(corresponding to the load generated by burning of the “Buk-type powder” of
the combustible layer of thickness i = 2.2 mm). Examples of the “stress vs time”
and “strain vs time” diagrams are presented in Fig. 3.
Tima ( ms ) * eo d
Fig. 3. Typical stress and strain diagram s at the loading rate o f 1505 M Pa/s.
52 ISSN 0556-171X. npo6neMbi npouHocmu, 2002, № 3
Experimental Study o f Concrete
Fig. 4. Typical “ stress-stra in” diagram s for three different (two cubical and one cylindrical)
concrete specim ens under the loads generated by burning o f the “B uk-type pow der.”
The average strength of the concrete in compression (as calculated from ten
samples), under the dynamic load was RC = 38.99 MPa. The average value of
maximal vertical deformation was £= 1120 ̂ m/m.
The average time of the load increase up to the moment of the specimen
fracture was 27 ms. Based on the medium values of the delta courses, determined
by digital methods with the use of digital filtration and the so-called “smoothing
windows,” the final plots of the local stress/strain relationships o(s) were
prepared (see Fig. 4). The elastic modulus of the concrete in compression Ec was
determined from the relationship [2, 3]:
0.4Rc - 0.5
Ec = s(0.4Rc) -s(0.5) [GPâ (1)
where s(0.4Rc) is the strain corresponding to the stress of 0.4Rc [MPa]; s(0.5) is
the strain corresponding to the stress of 0.5 MPa.
The elasticity modulus of the concrete at the load rate of 0.14 MPa/s was
26.8 GPa, while at the loading rate of 1505 MPa/s this parameter was 45.6 GPa.
C o n c l u s i o n s
1. The tests performed have shown that there exists a possibility of
conducting the verification testing of dynamic strength of structural concrete in
compression using standardized specimens.
2. With increasing loading rate, the strain level in concrete decreases what
can be attributed to the vanishing of elasticity face of the material (brittle fracture
occurs).
ISSN 0556-171X. npo6n.eubi npounocmu, 2002, N 3 53
R. Rekucki and L. Kruszka
3. In the tests performed, the increase in the material strength by 1.26 at
dynamic loading as compared to the static one, while the corresponding increase
in elastic modulus equaled to 1.7.
4. The technique proposed makes it possible to conduct testing of structural
concrete under dynamic loading conditions at a predetermined velocity of the load
increases increase up to the moment of specimens fracture.
Acknowledgement. This paper was prepared within the framework of the
research project No. 0T 00A 017 15 financed by the State Committee for
Scientific Research (Poland).
Р е з ю м е
Проведені експериментальні дослідження свідчать про вплив різної швид
кості деформування на міцність конструкційного бетону. Особлива увага_2 _ізосереджена на швидкості деформування 10 c , для якої проблематично
точно визначити механічні характеристики квазікрихких матеріалів. Наве
дено нову конструкцію системи вимірювання, в якій реалізуються комп’ю
теризоване одержання експериментальних даних, їхня обробка та графічне
зображення.
1. S. Cudzilo, L. Kruszka L., J. Pisera, and R. Rekucki, “Application of
explosive to determination resistance of concrete on dynamical loading. Part I
and II,” in: Proc. of VIII Technological-Scientific Conference on Military
Engineering, (Modlin, Poland, 1994), Warsaw (1994), pp. 136 - 151.
2. L. Kruszka and R. Rekucki, “Dynamic behaviour investigations of structural
concretes imposed pressure wave,” in: Proc. of 19th Symposium on
Experimental Mechanics of Solids (Jachranka, Poland, 2000), Warsaw
(2000), pp. 349 - 354.
3. R. Rekucki, “Experimental testing method of dynamical properties of brittle
materials subjected to explosive load,” in: Proc. of 19th Symposium on
Experimental Mechanics of Solids (Jachranka, Poland, 2000), Warsaw
(2000), pp. 456 - 461.
R eceived 14. 11. 2001
54 ISSN 0556-171X. Проблеми прочности, 2002, № 3
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