scholarly journals ПРОЕКТИРОВАНИЕ И ЭКСПЕРИМЕНТАЛЬНЫЕ ИССЛЕДОВАНИЯ СТАЛЕФИБРОБЕТОННОЙ ПЛИТЫ ПЕРЕКРЫТИЯ

World Science ◽  
2018 ◽  
pp. 28-32
Author(s):  
Сурьянинов Н. Г. ◽  
Корнеева И. Б.
Keyword(s):  
Crack Resistance ◽  
Bearing Capacity ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Concrete Slabs ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
Control Load

In the work, the design of the floor slab with five voids of steel fiber concrete, similar to a serial reinforced concrete slab, is proposed. Both plates are calculated in accordance with the regulations on the first and second limiting states. For experimental studies, a series of plates was made, each of which was tested before destruction. Scaling was used for all the plates, taking into account the design standards and technological capabilities of the laboratory.The loading of structures during testing was carried out in steps. Each step was 10% of the control load when checking the bearing capacity and crack resistance and 20% of the control load when checking the rigidity of structures. As a result of tests, the values of stresses and deflections were obtained as in theoretical calculations, the stresses in the concrete and steel fiber concrete slabs differ only slightly, and the deflections, especially up to 60% of the breaking load, differ several times, which confirms the much slower crack opening in the steel fiber concrete slabs. This suggests that at loads corresponding to the operational level, cracks will not open. The use of steel fiber concrete with preservation of linear reinforcement for the manufacture of hollow-core slabs allows to improve their characteristics, first of all - bearing capacity and crack resistance.

scholarly journals Comparative analysis of strength and deformation of reinforced concrete and steel fiber concrete slabs

2020 ◽  
Vol 166 ◽  
pp. 06003
Author(s):  
Mykola Surianinov ◽  
Stepan Neutov ◽  
Iryna Korneieva
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Bearing Capacity ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Experimental Studies ◽  
Concrete Slabs ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
The Moment

The results of experimental studies of the steel fiber influence on the bearing capacity, deformability and crack resistance of reinforced concrete multi-hollow plates are given. We investigated a serial floor slab and a similar one, but with the addition of steel fiber. Both plates are factory-made. For testing, the testing apparatus was designed and manufactured that made it possible to study full-size floor slabs in laboratory conditions. The tests were carried out according to a single-span scheme with the replacing equivalent load. The loading was carried out by applying two concentrated strip vertical loads along the plate width. The load was applied in steps of (0.04 ÷ 0.05) from the breaking load. Each stage ended with exposure lasting up to 10 minutes with fixing all the necessary parameters. Deformations were measured using dial gauges. From the moment the first crack appeared in the stretched zone of concrete, the process of crack formation and opening was monitored. At each level, using the Brunell tube, the width of their opening and height were measured. The moment of cracking in both slabs began at the same relative strain. It has been established that the bearing capacity and crack resistance of a slab of combined reinforcement using steel fiber are respectively 50 and 44% higher than that of a similar reinforced concrete slab. The maximum deflection of the slab of combined reinforcement is 37.5% lower than that of conventional reinforced concrete. The destruction of both slabs occurred under loads, when the relative deformations in the compressed zone of concrete reached 0.80×10-3 and 1.10×10-3 for reinforced concrete and steel-fiber concrete slabs, respectively, the difference is 37.5%.

scholarly journals DEFORMABILITY AND CRACK RESISTANCE OF AIRFIELD SLABS

2021 ◽  
pp. 52-61
Author(s):  
M.G. Surianinov ◽  
◽  
S.P. Neutov ◽  
I.B. Korneeva ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Crack Opening ◽  
Experimental Studies ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Fiber Concrete ◽  
Steel Fiber Concrete

Abstract. The results of experimental studies of deformability and crack resistance of models of airfield slabs made of reinforced concrete and steel fiber concrete are presented. Two series of plates were tested ‒ three models of reinforced concrete and three models with steel fiber added to the concrete mixture in amount of 1% of the total volume of the product. The load was applied in small steps, the instrument readings were recorded twice at each step, and the crack opening width was measured starting from the moment of the first crack formation. Dial gauges and deflectometers were used as measuring instruments. According to the normative documents acting in Ukraine, one of two possible loading schemes was considered ‒ with the loading by the concentrated force applied on the cantilever part of a plate. The plate models were tested on a specially made stand which consisted of four supporting struts connected in pairs by beams. The airfield slab was supported by the beams. The load was applied along the width of the plate in steps ‒ 0.05 of the destructive load, along two concentrated vertical strips. Each degree of load ended with a five-minute dwell time, at the beginning and end of which readings were taken on the measuring instruments. The deformations at the same levels were measured with dial gauges. The process of crack formation was observed with a Brinell tube in the places of the greatest crack opening. It follows from the obtained results that the process of cracking in the fiber concrete slab begins at higher loads than in the reinforced concrete slab. The final and initial crack opening widths of all cracks in the fiber concrete slab are significantly lower than in the reinforced concrete slab. The deformations in steel-fiber concrete slabs during the application of load in the cantilever part, both for compressed and stretched fibers are higher than in reinforced concrete slabs. At the initial stages of load application in the cantilevered part of the slabs, the deflections increase in a linear relationship. The curves get non-linear character for airfield slabs made of reinforced concrete when the load reaches the level of 10÷25 kN, for steel-fiber-concrete slabs ‒ 15÷30 kN. In reinforced concrete slabs, the non-linearity starts a little earlier and is expressed more clearly. Experimental studies show that dispersed reinforcement of airfield slabs with steel fiber leads to their higher crack resistance.

scholarly journals Bearing capacity of steel-fiber-concrete slabs with biaxially prestressed reinforcement

2020 ◽  
pp. 292-301
Author(s):  
Oleksandr Zhuravskyi
Keyword(s):  
Bearing Capacity ◽  
Steel Fiber ◽  
Experimental Studies ◽  
Biaxial Compression ◽  
Concrete Slabs ◽  
Deformation Method ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
The Difference ◽  
Prestressed Reinforcement

The aim of the research is to obtain new experimental data of biaxially prestressed steel-fiber-concrete slabs under transverse loading and to develop a method for calculating their bearing capacity. Experimental-theoretical studies of biaxially prestressed steel-fiber-concrete slabs under the action of a uniformly distributed load were performed. Experimental studies were performed on plates measuring 40x800x800 mm with prestressed reinforcement Ø5Bp-II in two directions. Samples of the first series were reinforced with a mixture of steel fibers of STAFIB 50/1.0 and STAFIB 30/0.6 with anchors at the ends, the percentage of which was 0.5% by volume of each fiber. The samples of the second series contained 1.0% by volume of NOVOKON URW 50/1.0 corrugated fibers. A method for calculating steel-fiber-concrete (SFB) slabs based on the deformation method is proposed. This takes into account the real diagram "σ-ε" for uniaxial and biaxial compression of steel-fiber-concrete and increase the compressive strength of steel-fiber-concrete under conditions of biaxial compression. Stress losses in the reinforcement from creep and shrinkage deformations of steel-fiber-concrete are also taken into account. The results of calculation of experimental samples and their comparison with the results of experimental researches are given. They showed sufficient convergence. The difference was 1.1… 2.5%. It is established that the bearing capacity of biaxially prestressed slabs is 1.55… 1.61 times higher than unstressed slabs and 42.4… 55.5% higher than uniaxially stressed slabs.

scholarly journals LABORATORY TESTING OF STEEL FIBER CONCRETE PRISM FOR TENSION IN BENDING

2020 ◽  
pp. 105-113
Author(s):  
M.G. Surianinov ◽  
◽  
S.P. Neutov ◽  
I.B. Korneeva ◽  
I.K. Kalchev ◽  
...  
Keyword(s):  
Crack Resistance ◽  
Bearing Capacity ◽  
Steel Fiber ◽  
Fiber Reinforcement ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Fiber Concrete ◽  
Steel Fiber Concrete

Abstract. Laboratory bending tests of concrete and steel-fiber-concrete prisms were carried out. The concrete matrix for all prisms is made of a concrete mixture of the same composition with a coarse aggregate size up to 10 mm and a water-cement ratio that allows correct mixing of the ready mixture with fiber, so that the latter is evenly distributed over the sample volume. Fiber reinforcement is 1% for all three types of fiber, a fiber made of the same steel with an ultimate strength of 1335 MPa, fiber length 50 mm, diameter 1 mm is used. Fibers differ only in shape, which makes it possible to compare test results across series without correction factors. Concrete samples without fiber are considered as control samples. As a result of laboratory tests, data sets were obtained and analyzed, which are presented in the form of diagrams. Different types of steel fiber show different increases in the load at the beginning of cracking and load-bearing capacity. The most profitable from this point of view is the addition of anchor fiber to concrete, the least – wave fiber. However, the presence of any of the considered steel fibers in the mixture significantly increases the load-bearing capacity of the sample. In addition, the type of destruction of such a sample changes from brittle to viscous. We also studied the deformability of samples with different fiber reinforcement and plotted the dependence of the relative longitudinal strain on the load. Before the crack formation begins, there is a direct proportionality between the load and the strain with the appearance of cracks, the slope of the graphs changes sharply. When the load-bearing capacity is lost, steel fiber-reinforced concrete samples are restrained from final destruction. The use of steel fiber in concrete on average increases the crack resistance by 40%, and the load-bearing capacity by 64%. Compared with samples without fiber reinforcement, samples with anchor fiber show an increase in load-bearing capacity by 89%, and crack resistance by 61%. When using flattened fiber, these values are 56% and 32%, and for wave fiber – 47% and 25%, respectively. The use of steel fiber in the manufacture of concrete mix avoids the brittle nature of destruction.

scholarly journals EXPERIMENTAL STUDIES OF DEFORMABILITY AND FRACTURE RESISTANCE OF AIRFIELD SLABS ON MODELS

2021 ◽  
Vol 3 (2) ◽  
pp. 64-74
Author(s):  
I. Korneieva ◽  
◽  
D. Kirichenko ◽  
O. Shyliaiev ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Slab ◽  
Crack Opening ◽  
Experimental Studies ◽  
Measuring Instruments ◽  
Reinforced Concrete Slab ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
Opening Width

The results of experimental studies of deformability and crack resistance of models of aerodrome slabs made of reinforced concrete and steel-fiber concrete, made on the basis of serial slab PAG-18 taking into account the scale factor, are presented. Two series of slabs were tested - two models of reinforced concrete and two models with one-percent dispersed reinforcement. The load was applied in steps, the instrument readings were recorded twice at each step and the crack opening width was measured starting from the moment of the first crack formation. Dial gauges, deflectometer and microscope MPB-3 were used as measuring instruments. In accordance with the normative documents acting in Ukraine, one of two possible loading schemes was considered - with the loading by the concentrated force applied in the span part of a plate which had a hinged support along its short sides. Plate models were tested on a specially made stand. Each load step ended with a five-minute dwell time, at the beginning and the end of which readings were taken on the measuring instruments. The deformations at the same levels were measured with dial gauges. The process of crack formation was observed with a Brinell tube in the places of the greatest crack opening. Breaking load for fiber concrete slab was 1.52 times higher than for reinforced concrete slab, and the moment of cracking initiation was 1.22 times higher. The process of cracking in the fiber concrete slab begins at higher loads than in the reinforced concrete slab. The initial crack opening width of the slabs is almost the same, and the final crack opening width of all the cracks in the fiber concrete slab is significantly lower than in the reinforced concrete slab. The deformations in steel-fiber concrete slabs when the load is applied in the span, both for compressed and stretched fibers, are higher than in reinforced concrete slabs. The experimental studies indicate that dispersed reinforcement of airfield slabs with steel fiber leads to their higher crack resistance.

scholarly journals Experimental and theoretical studies of biaxially prestressed steel-fiber-concrete slabs.

2018 ◽  
Vol 2 (3) ◽  
pp. 10-14
Author(s):  
Oleksandr Zhuravskyi ◽  
Andriy Gorobetc
Keyword(s):  
Steel Fiber ◽  
Physical Nonlinearity ◽  
Concrete Slabs ◽  
Theoretical Studies ◽  
Transverse Loading ◽  
Software Complex ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
Experimental And Theoretical Studies

The article presents the results of experimental and theoretical studies of strength and deformability of steel-fiber concrete double-sided pre-stress slabs under the action of transverse loading. The simulation of such plates in the software complex LIRA-SAPR was performed taking into account the physical nonlinearity of materials.

scholarly journals Influence of long-term compressive stresses on strength of concrete and steel-fiber concrete prismatic element

2018 ◽  
Vol 230 ◽  
pp. 02020
Author(s):  
Stepan Neutov ◽  
Maryna Sydorchuk ◽  
Oleksii Shyliaiev
Keyword(s):  
Bearing Capacity ◽  
Steel Fiber ◽  
Rupture Strength ◽  
Load Level ◽  
Short Term ◽  
Fiber Concrete ◽  
Steel Fiber Concrete ◽  
Long Acting ◽  
Acting Load

The strength and deformation characteristics of concrete and steel-fiber concrete on prisms and cubes are determined. Short-term and long-term tests of the samples were carried out taking into account the recommendations of the regulatory documents for the testing of concrete. Loading of samples with a long load was carried out in force installations (stands) consisting of four metal rods to which rigid loading plates were fixed at certain levels with threaded connections. To cover the entire operational spectrum of the stress state of real reinforced concrete elements, levels of 0.3; 0.4; 0.5; 0.67 and 0.8 from the short-term destructive load were adopted as long-term loading levels. All samples, which were more than a year under the action of a long-acting load, increased their bearing capacity. Prisms from steel-fiber concrete, which were under the influence of a long-acting load during 370 days, increased the bearing capacity, depending on the level of load, by 30-50%. The higher load level, the higher the creep rupture strength. When the loading was repeated before the destruction, the deformations of steel-fiberconcrete prisms changed linearly.

Experimental Studies of Reinforced Concrete and Fiber-Reinforced Concrete Beams with Short-Term and Long-Term Loads

2019 ◽  
Vol 968 ◽  
pp. 227-233 ◽  
Author(s):  
Stepan Neutov ◽  
Maryna Sydorchuk ◽  
Mykola Surianinov
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Short Term ◽  
Ordinary Concrete ◽  
Fiber Concrete ◽  
Steel Fiber Concrete

Experimental studies of the stress-strain state of reinforced concrete and fiber-reinforced concrete beams under short-term and long-term loads were carried out. The tests were carried out on three series of beams of different types - from ordinary concrete, steel fiber concrete and combined section, when the lower zone of the beam with a height of0.5his made of steel fiber concrete, and the upper one is made of ordinary concrete. During short-term loading, the load was applied in steps with a 10-minute exposure at each step to failure or to a predetermined level of a continuously acting load. In the interval between the steps, the process of cracking was tracked. After reaching a given level of loading, the load was fixed and maintained unchanged with a spring cassette for 300 days. Deformations were measured using strain gauges and dial gauges. Deflections and relative deformations of the extreme upper and extreme lower fibers for three types of beams are determined. It has been established that stabilization of deflections in beams from steel fiber concrete occurs much earlier (100 days) than in beams made of ordinary concrete (175 days). Studies have shown that the beams of ordinary concrete in the process of long-acting load lowered the carrying capacity by 5.5%. The bearing capacity of steel concrete beams, in contrast, increased by 7.6%.

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