Volume 04 Issue 08-2024
26
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
04
ISSUE
08
Pages:
26-31
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
ABSTRACT
This article presents the methods of calculating the fracture resistance of bending concrete beams with basalt
reinforcement on vertical (normal) sections, the conducted research and the analysis of comparing the experimental
results with the calculated results.
KEYWORDS
Mirror composite materials, basalt-plastic reinforcements, strength, stress-strain state, crack formation, loading
stages, shear range, deformations, breaking moment.
INTRODUCTION
Today, in the world, a lot of scientific and research
work is being carried out, aimed at ensuring their
priority, strength and longevity, using carbon, glass
and basalt reinforced concrete structures made on the
basis of mirror composite materials in the construction
of buildings and structures. In construction practice,
using mirror composite reinforcements, conducting
research in the directions of increasing the fire
resistance and elasticity module of concrete, and
improving the stress-deformation state, strength, and
crack resistance properties of bending elements has
become one of the urgent tasks.
Research Article
CALCULATION OF STRENGTH OF FLEXIBLE CONCRETE BEAMS WITH
BASALT REINFORCEMENT ON VERTICAL SECTIONS
Submission Date:
Aug 09, 2024,
Accepted Date:
Aug 14, 2024,
Published Date:
Aug 19, 2024
Crossref doi:
https://doi.org/10.37547/ajast/Volume04Issue08-04
Mirzaaxmedova Ugiloy Abduxalimjonovna
Doctoral student at FarPI, Uzbekistan
Razzakov Sobirjon Juraevich
Professor at NamECI, Uzbekistan
Journal
Website:
https://theusajournals.
com/index.php/ajast
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 04 Issue 08-2024
27
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
04
ISSUE
08
Pages:
26-31
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
Therefore, it is advisable to conduct complex
experimental and theoretical studies to determine the
state of stress-deformation, strength, formation of
cracks in their constructions, development, failure
patterns and uniformity of bending concrete beams
with basalt reinforcement under the influence of
external forces.
The main part.
To conduct an experimental study, test
sample beams with a rectangular cross-section were
prepared. Ordinary heavy concrete was used for the
beams. Portland cement of the "Yasin" cement factory
in Fergana region was used as a binder. Granite flint
and quartz river sand were used as fillers. The
composition of the concrete was chosen so that the
cubic strength was equal to the compressive strength
corresponding to the V20-V25 class.
12 sample beams with cross-sectional dimensions
b×h=16×30 cm, length l=240 cm, support interval
l_o=210 cm were tested on a specially prepared test
stand. As working fittings, Ø12, Ø14, Ø16 BPA were
placed in the stretching area, Ø10 BPA in the
compression area, Ø4, Ø8 BPAs were placed as clamps,
with a step of 15 (10)cm.
The strength of flexural concrete beams with basalt
reinforcement was determined depending on the
distance between the element supports, the amount
of load, the strength of the concrete and the
reinforcement of the beams.
RESULTS AND DISCUSSION
According to the results of the conducted test studies,
it was found that the flexural concrete beam structures
reinforced with basalt reinforcements tested under
the influence of external forces are almost qualitatively
similar to the flexural structures with steel
reinforcement.
According to the values of deformations in concrete
and reinforcement during the test research, it was
determined that cracks are formed in the sample
beams. At the same time, the surfaces and side
surfaces of the beams were carefully monitored during
loading. In this case, the fact that the load has a
relatively small value (~ 0.05Fult) during the
observation and loading stages, allowed to determine
the amount of the load during the crack formation
during the test.
In all tested beams, initially vertical cracks were formed
in the pure bending region, and as the amount of load
in the loading stages increased, cracks inclined to the
longitudinal axis of the beam were also formed in the
load span (shear span).
It was observed that the value of the bending
moments Mcrc during the formation of cracks in the
sample beams depends on the value of the distance
"a" (shear interval) between the load and the support.
When the distance between the supports is a=70cm in
the beams of the series sample, (
𝑎
ℎ
= 2,59
) vertical
cracks were formed at bending moments equal to
𝑀
𝑐𝑟𝑐
т
= 9,2 − 9,7 кНм
. In this case, the ratio of the
crack forming moment to the breaking moment was
𝑀
𝑐𝑟𝑐
т
𝑀
𝑢𝑙𝑡
т
= 0,209
. In the BPPA I-3 beam of the I-series, when
the distance between the supports is a=40 cm, (
𝑎
ℎ
=
1,48
)the vertical crack
𝑀
𝑐𝑟𝑐
т
nng value is
𝑀
𝑐𝑟𝑐
т
=
7,9 кНм
,
𝑀
𝑐𝑟𝑐
т
𝑀
𝑢𝑙𝑡
т
= 0,28
.
Volume 04 Issue 08-2024
28
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
04
ISSUE
08
Pages:
26-31
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
The distance between the supports in the II-series
sample beams is a=70cm. When the distance between
the supports in the II-series sample beams is a=70cm,
(
𝑎
ℎ
= 2,59
) vertical cracks are
𝑀
𝑐𝑟𝑐
т
= 8,9 − 9,1 кНм
,,
equal to in bending moments was equal to
𝑀
𝑐𝑟𝑐
т
𝑀
𝑢𝑙𝑡
т
=
0,224
.
Due to the low strength of the concrete of sample
beams of the III-series compared to other sample
beams, vertical cracks were formed earlier, that is, the
amount of moments in the formation of cracks was 7-
11% less. In this case, when the distance between the
supports is a=70cm, (
𝑎
ℎ
= 2,59
) vertical cracks
𝑀
𝑐𝑟𝑐
т
=
7,9 − 8,3 кНм
, the ratio decreases at equal bending
moments,
𝑀
𝑐𝑟𝑐
т
𝑀
𝑢𝑙𝑡
т
= 0,173
.
In sample beams of series IV, the distance between the
supports was tested at values of
а=40см (
𝑎
ℎ
0
= 1,48
).
The first vertical cracks were formed in sample beams
of the IV-series at values of
𝑀
𝑐𝑟𝑐
т
= 12,7 − 13,03 кНм
.
The corresponding value was
𝑀
𝑐𝑟𝑐
т
𝑀
𝑢𝑙𝑡
т
= 0,33
.
The ratio of the experimental values of the cracking
moments to the calculated values for sample beams of
I, II and III-series had values less than 1 and ranged from
0.67 to 0.92, their average value was equal to 0.73.
According to the analysis of calculated and
experimental values, vertical cracks are formed at
loads 25-30% lower than the calculated values. For IV-
series specimen beams, values greater than 1 were
obtained, and the ratio of experimental and calculated
cracking moments was between 1.05 and 1.07 (Fig. 1).
Figure 1. Formation and development of cracks in sample beams
The values of the experimental M_crc^т and calculated
M_crc^
ҳ
bending moments perpendicular to the
element's longitudinal axis in the sample beams are
presented in Table 1.
Volume 04 Issue 08-2024
29
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
04
ISSUE
08
Pages:
26-31
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
Formation of vertical cracks in sample beams
A sample
beam cipher
The
distance
between
the forces,
cm
Bending moment in the formation
of vertical cracks, kNm
М
𝑢𝑙𝑡
т
М
с𝑟𝑐
т
М
𝑢𝑙𝑡
т
М
с𝑟𝑐
т
М
с𝑟𝑐
х
Experimental
М
с𝑟𝑐
т
Accounting
М
с𝑟𝑐
х
BBPA I-1
70
9,7
12,95
25,34
0,383
0,75
BBPA I-2
70
9,2
12,60
25,06
0,367
0,73
BBPA I-3
40
7,9
10,50
19,20
0,411
0,752
BBPA II-1
70
9,1
12,60
25,34
0,36
0,72
BBPA II-2
70
9,0
13,06
23,38
0,384
0,69
BBPA II-3
70
8,9
13,30
22,26
0,40
0,67
BBPA III-1
70
7,9
10,56
21,18
0,373
0,75
BBPA III-2
70
9,3
10,09
22,42
0,414
0,922
BBPA III-3
70
8,3
9,91
20,09
0,413
0,837
BBPA IV-1
40
11,5
10,94
27,08
0,424
1,051
BBPA IV-2
40
12,7
11,87
29,80
0,426
1,069
BBPA IV-3
40
13,03
12,27
29,68
0,44
1,061
When the load was applied to the beams of the tested
sample, 1.2 vertical cracks first appeared in the beams
in the area of pure bending of the element at II and
subsequent stages of loading, and new vertical cracks
were formed as the load increased. The opening width
of the initially formed cracks was 0.03-0.05 mm. As the
loads increased, vertical cracks developed, the crack
tips were observed to grow towards the compressive
zone of the member, and at the same time, the crack
opening width also increased.
When the destructive load in the loading stages
reached about half, the opening width of the vertical
cracks was asrc=0.25-0.35mm, the increase of the load
in the later stages caused the rapid development of the
vertical cracks and the significant increase in the
opening width.
The values of
𝑀
𝑐𝑟𝑐
ҳ
range from 9.91 kN∙m to 13.30 kN∙m
based on theoretical calculations. The average value of
Mcrch was equal to 11.60 kN∙m. The difference
between the average value of
𝑀
𝑐𝑟𝑐
ҳ
and the smallest
and largest values is 2.01 kN
∙
m (0.85%) and 1.72 kN
∙
m
Volume 04 Issue 08-2024
30
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
04
ISSUE
08
Pages:
26-31
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
(1.18%), respectively. Almost constant values were
obtained for the values of
𝑀
𝑐𝑟𝑐
ҳ
in the calculations.
In the values of the bending moments
𝑀
𝑐𝑟𝑐
т
in the
formation of a vertical crack, there were big
differences. In the experiments, the values of
𝑀
𝑐𝑟𝑐
т
of
the sample beams of the III series were 7.5-
9.3 kN∙m,
and the values of the sample beams of the IV series
were 12.7-13.03 kN
∙
m.
During the tests, the opening width and length of the
vertical cracks formed in all sample beams were
measured. The obtained results were processed and
summarized and graphs were developed. (Figure 2).
Figure 2. Vertical crack opening width in sample beams. 1,2,3,4 is the order number of
cracks. ___________ - experimental, computational
CONCLUSIONS
1) According to the results of the test experiment, it
was observed that the values of M_crc^t change in
accordance with the values of the tensile strength of
Volume 04 Issue 08-2024
31
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
04
ISSUE
08
Pages:
26-31
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
concrete R_(bt,ser). As an example, we can cite sample
beams of the III series. Accordingly, since the concrete
of the sample beams of this series is made of low-
strength concrete, it was determined that the moment
of cracking is 1.74 times smaller than that of the beams
of other series tested under the same conditions.
2) The ratio of the experimental M_crc^T to the
calculated M_crc^h was 1.21 on average, except for the
samples of the III series. For samples of the III series,
this ratio was 0.833. It was found that the average
value of the experimental crack-inducing moments in
samples other than the III-series is equal to 20.0% of the
breaking moments. In the samples of this series, cracks
occurred at loads equal to 10.0% of the breaking load.
3) It was found that the results of calculation of the
opening width of vertical cracks in relation to the
longitudinal axis of the element according to the
method given in ShNQ 2.03.14.18 "Concrete
constructions with composite polymer reinforcement"
satisfactorily agree with the laws and quantities of
changes obtained in the experiments.
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1.
ШН
Қ
2.03.14.18
«Композит
полимер
арматурали
бетон
конструкциялар»
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Brik V.B., Performance Evaluation of3-D Basalt
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Mirzaakhmedova U. A. ISSUES OF INCREASING
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Razzakov S. J., Mirzaakhmedova U. A. Composite
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