scholarly journals Research on the Fractal Characteristics and Energy Dissipation of Basalt Fiber Reinforced Concrete after Exposure to Elevated Temperatures under Impact Loading

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1902
Author(s):  
Wenbiao Liang ◽  
Junhai Zhao ◽  
Yan Li ◽  
Yue Zhai
Keyword(s):  
Fractal Dimension ◽  
Energy Consumption ◽  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Impact Velocity ◽  
Impact Loading ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Fractal Characteristics

The fractal characteristics and energy dissipation of basalt fiber reinforced concrete (BFRC) with five kinds of fiber volume contents (0.0%, 0.1%, 0.2%, 0.3%, 0.4%) after exposure to different temperatures (20 °C, 200 °C, 400 °C, 600 °C, 800 °C) under impact loading were investigated by using a 50 mm diameter split Hopkinson pressure bar (SHPB) apparatus. Scale-mass distribution rules and fractal dimension characteristics of fragments were studied based on the screening statistical method and the fractal theory. Furthermore, the relationship between the energy consumption density and the fractal dimension of fragments was established, and the effects of fiber content, temperature and impact velocity on fractal dimension and absorption energy were analyzed. The results show that the crushing severity of fragments and fractal dimension increase with the impact velocity under the same fiber content. The energy consumption density increases first and then decreases with increasing fiber content, and also decreases with increasing temperature. When the temperature and fiber content remain unchanged, the energy consumption density increases linearly with the increasing fractal dimension, and under the same impact velocity and temperature, there is no obvious linear relationship between energy consumption density and fractal dimension.

scholarly journals Research on Fractal Characteristics and Energy Dissipation of Concrete Suffered Freeze-Thaw Cycle Action and Impact Loading

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2585 ◽  
Author(s):  
Yan Li ◽  
Yue Zhai ◽  
Xuyang Liu ◽  
Wenbiao Liang
Keyword(s):  
Fractal Dimension ◽  
Energy Consumption ◽  
Energy Dissipation ◽  
Impact Loading ◽  
Physical Parameters ◽  
Impact Compression ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Fractal Characteristics

In order to study the fractal characteristics and energy dissipation of concrete suffered freeze-thaw cycle actions and impact loading, C35 concrete was taken as the research object in this paper, and freeze-thaw cycle tests were carried out with a freeze-thaw range of −20 °C~20 °C and a freeze-thaw frequency of 0~50 times. The degradation characteristics of concrete material and the variation rules of basic physical parameters under various freeze-thaw cycle conditions were obtained consequently. By using the SHPB (separated Hopkinson pressure bar) test device, impact compression tests of concrete specimens under different freeze-thaw cycle actions were developed, then the process of impact crushing and the mechanism of damage evolution were analyzed. Based on the screening statistical method and the fractal theory, the scale-mass distribution rules and fractal dimension characteristics of crushing blocks are investigated. Furthermore, the absorption energy, fracture energy and block kinetic energy of concrete under different conditions were calculated according to the energy dissipation principle of SHPB test. The relationship between the energy consumption density and the fractal dimension of fragments was established, and the coupling effect mechanism of freeze-thaw cycle action and strain rate effect on the fractal characteristics and energy consumption was revealed additionally. The research results show that the concrete under different freeze-thaw cycle conditions and impact loading speeds has fractal properties from the microscopic damage to the macroscopic fracture. The energy dissipation is intrinsically related to the fractal characteristics, and the energy consumption density increases with the increase of the fractal dimension under a certain freeze-thaw cycle condition. When at a certain loading speed, with the growth of freeze-thaw cycles, the energy consumption density reduces under the same fractal dimension, while the fractal dimension improves under the same energy consumption density.

scholarly journals Study on the Fractal Characteristics of the Pomegranate Biotite Schist under Impact Loading

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jianguo Wang ◽  
Ting Zuo ◽  
Xianglong Li ◽  
Zihao Tao ◽  
Jun Ma
Keyword(s):  
Compressive Strength ◽  
Fractal Dimension ◽  
Energy Consumption ◽  
Energy Dissipation ◽  
Strain Rate ◽  
Power Relationship ◽  
Strain Rates ◽  
Biotite Schist ◽  
Fractal Characteristics ◽  
Dynamic Compressive Strength

In order to study the fractal characteristics of the pomegranate biotite schist under the effect of blasting loads, a one-dimensional SHPB impact test was carried out to test the dynamic compressive strength, damage morphology, fracture energy dissipation density, and other parameters of the rocks under different strain rates; besides, sieve tests were conducted to count the mass fractal characteristics of the crushed masses under different strain rates to calculate the fractal dimension of the crushed rock D . Finally, the relationships between fractal dimension and dynamic compressive strength, crushing characteristics, and energy dissipation characteristics were analysed. The results show that under different impact loads, the strain rate effect of the rock is significant and the dynamic compressive strength increases with the increasing strain rate, and they show a multiplicative power relationship. The higher the strain rate of the rock, the deeper the fragmentation and the higher the fractal dimension, and the fractal dimension and rock crushing energy density are multiplied by a power relationship. By performing the comparative analysis of the pomegranate biotite schist, a reasonable strain rate range of 78.75 s-1~82.51 s-1 and a reasonable crushing energy consumption density range of 0.78 J·cm-3~0.92 J·cm-3 were determined. This research provides a great reference for the analysis of dynamic crushing mechanism, crushing block size distribution, and crushing energy consumption of the roadway surrounding rock.

scholarly journals Study on Mechanical Properties of Basalt Fiber-Reinforced Concrete with High Content of Stone Powder at High Temperatures

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lina Xu ◽  
Daohan Song ◽  
Ning Liu ◽  
Wei Tian
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Temperature ◽  
Unconfined Compressive Strength ◽  
Fiber Length ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Acoustic Response

Concrete materials are an important part of global structure, and their fire resistance directly affects the safety of buildings and tunnels. In this study, basalt fiber was used to reinforce concrete with high content of stone powder in order to enhance its high-temperature performance. The mechanical properties and ultrasonic characteristics at different temperatures were studied using the cube compressive strength test and nonlinear ultrasonic test. The results indicated that the addition of basalt fiber in specimens improved their compressive strength; however, this strength did not continuously increase with increases in the fiber length and fiber content, and the optimal values for fiber length and fiber content were determined to be 12 mm and 1 kg/m3 at 600°C, respectively. With increases in temperature, the unconfined compressive strength increased first and then decreased. When the temperature was 400°C, the unconfined compressive strength of the specimens reached their highest values and then decreased. When the temperature was 400°C and 600°C, the strength of the stone powder concrete with fiber was higher than that without fiber, which shows that fiber can improve the mechanical properties of concrete at high temperatures. Based on the Box-Behnken design (BBD) method, the unconfined compressive strength response regression model of basalt fiber-reinforced concrete with high content of stone powder, which follows parameters including fiber content, fiber length, and temperature at high-temperature environments, was established, and it was found that the interaction of fiber content, fiber length, and the temperature was significant based on multifactor interaction analysis. The analysis of ultrasonic signals based on the S transform showed that, with increases in temperature, the amplitudes of the acoustic response signals, the corresponding frequency spectrum, and the time-frequency spectrum were clearly reduced. At the same temperature, the amplitudes of the acoustic response signals of different concrete testing blocks did not change much and remained at the same level.

scholarly journals Study on the Fracture Toughness of Polypropylene–Basalt Fiber-Reinforced Concrete

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Ninghui Liang ◽  
Lianxi Ren ◽  
Shuo Tian ◽  
Xinrong Liu ◽  
Zuliang Zhong ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Reinforced Concrete ◽  
Polypropylene Fiber ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Negative Effects ◽  
Initial Fracture

AbstractTo study the hybrid effects of polypropylene fiber and basalt fiber on the fracture toughness of concrete, 13 groups of notched concrete beam specimens with different fiber contents and mass ratios were prepared for the three-point bending test. Based on acoustic emission monitoring data, the initiation cracking load and instability load of each group of specimens were obtained, and the fracture toughness parameters were calculated according to the double-K fracture criterion. The test results show that the basalt fiber-reinforced concrete has a greater increase in initial fracture toughness, and the toughness of coarse polypropylene fiber-reinforced concrete is more unstable. Moreover, after the coarse polypropylene fiber content reaches 6 kg/m3 and the basalt fiber content reaches 3 kg/m3, increasing the content will not significantly improve the fracture toughness of the concrete. The polypropylene–basalt fiber will produce positive and negative effects when mixed, and the mass ratio of 2:1 was optimal. Finally, the fitting analysis revealed that the fracture process of polypropylene–basalt fiber-reinforced concrete (PBFRC) can be objectively described by the bilinear softening constitutive curve improved by Xu and Reinhardt.

scholarly journals Experimental Investigation of Shear Behavior of Two-Span Fiber Reinforced Concrete Beams

2019 ◽  
Vol 65 (2) ◽  
pp. 35-55 ◽  
Author(s):  
J. Krassowska ◽  
M. Kosior-Kazberuk
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Basalt Fiber ◽  
Shear Capacity ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
Shear Reinforcement ◽  
Fiber Reinforced

AbstractExperimental tests were carried out to assess the failure model of steel and basalt fiber reinforced concrete two-span beams. Experimental research was focused on observing the changes in behavior of tested elements in dependence on the ratio of shear reinforcement and type of fiber. The beams had varied stirrup spacing. The steel fiber content was 78.5 kg/m3 (1.0% by vol.) and basalt fiber content was 5.0 kg/m3 (0.19% by vol.). Concrete beams without fibers were also examined. Two-span beams with a cross-section of 120×300 mm and a length of 4150 mm were loaded in a five-point bending test. Shear or flexural capacity of tested members was recorded. The effectiveness of both sorts of fibers as shear reinforcement was assessed and the differences were discussed. It was shown that fibers control the cracking process and the values of deflections and strains. Fibers clearly enhance the shear capacity of reinforced concrete beams.

Study on Bond Properties of BFRP Bars to Basalt Fiber Reinforced Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1251-1256 ◽  
Author(s):  
Qiao Wei Bi ◽  
Qing Xiang Wang ◽  
Hui Wang
Keyword(s):  
Reinforced Concrete ◽  
Bonding Strength ◽  
Basalt Fiber ◽  
Concrete Specimen ◽  
Edge Length ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Bonding Length

In order to study the bonding characteristic of the BFRP(Basalt Fiber Reinforced Plastics for short) bars and the basalt fiber reinforced concrete, the BFRP was embedded into the cubic concrete specimen which mixed the basalt fiber sized the edge length 150 mm. By changing the diameter of the BFRP, the bonding length of the BFRP and the basalt fiber volume content of the basalt fiber reinforced concrete, the experimental results indicate that the average bonding strength decreased while the bonding length increased and it become weaker while the diameter of the BFRP was bigger, and it shows the best effect of the bonding strength when its fiber content was 0.1% comparing with three kinds of fiber content. The bond-slip constitutive model of BFRP bar and the basalt fiber concrete corresponded to the continuous curve model.

scholarly journals Shear behavior of steel or basalt fiber reinforced concrete beams without stirrup reinforcement

2017 ◽  
Vol 4 (20) ◽  
pp. 391-404
Author(s):  
Julita Krassowska ◽  
Marta Kosior-Kazberuk
Keyword(s):  
Reinforced Concrete ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Basalt Fiber ◽  
Shear Behavior ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Shear Reinforcement ◽  
Fiber Reinforced

The paper presents the results of a comprehensive investigation aimed at studying the shear behavior of basalt or steel fiber-reinforced concrete (BFRC or SFRC) beams, as well as analyzing the possibility of using basalt or steel fibers as a minimum shear reinforcement. Two-span reinforced concrete beams with the cross-section of 8×16 cm and length of 200 cm and diversified spacing of stirrups were tested. Steel stirrups or alternatively steel or basalt fibers were used as a shear reinforcement. Steel fiber content was 80 and 120 kg/m3and basalt fiber content was 2.5 and 5.0 kg/m3. The shear behavior and/or bending capacity of SFRC and BFRC beams were studied. The result indicated that fibers can be safely used as a minimum shear reinforcement.

scholarly journals Fractal Dimension of Basalt Fiber Reinforced Concrete (BFRC) and Its Correlations to Pore Structure, Strength and Shrinkage

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3238
Author(s):  
Yue Li ◽  
Aiqin Shen ◽  
Hua Wu
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Pore Size ◽  
Pore Diameter ◽  
Size Range ◽  
Basalt Fiber ◽  
Shrinkage Strain ◽  
Fiber Reinforced Concrete ◽  
Average Pore ◽  
Fractal Characteristics

In this study, we focused on exploring the correlations between the pore surface fractal dimensions and the pore structure parameters, strength and shrinkage properties of basalt fiber-reinforced concrete (BFRC). The pore structure of BFRCs with various fiber contents and fiber lengths was investigated using mercury intrusion porosimetry (MIP) measurements. Through Zhang’s model, the fractal characteristics of BFRCs in the whole pore size range and in different pore size ranges were calculated from the MIP test data. The results showed that the addition of BF increased the total porosity, total pore volume and pore area but decreased the average pore diameter, indicating that BFs refined the pore structure of the concrete. BFRC presented obvious fractal characteristics in the entire pore-size range and individual pore-size ranges; generally, the fractal dimension increased with increasing fiber content. Moreover, correlation analysis suggested that the fractal dimension of BFRC in the whole pore-size range (FD) was closely related to the fractal dimension in the macropore region (Dm) and average pore diameter (APD). The influence of pore structure factors on mechanical strength and shrinkage was studied by grey correlation theory, and the results showed that Dm showed positive correlations with strength and fracture energy, with increasing Dm tending to strengthen and toughen the concrete. An increase in fiber content and length was detrimental to reducing the drying shrinkage strain. In the transition pore region, the fractal dimension (Dt) at diameters ranging from 20 to 50 nm and shrinkage strain exhibited a highly linear relation. These results merit careful consideration in macro-property evaluation by using the pore surface fractal dimension in a specific region instead of the whole region. Finally, grey target theory was applied to evaluate the rank of the mechanical strength and shrinkage of concrete, and the results showed that the overall properties of concrete with a BF length of 18 mm and a BF content of 0.06% ranked the best.

scholarly journals Ductility and flexure of lightweight expanded clay basalt fiber reinforced concrete slab

2021 ◽  
Vol 17 (1) ◽  
pp. 74-81
Author(s):  
Vera V. Galishnikova ◽  
Alireza Heidari ◽  
Paschal C. Chiadighikaobi ◽  
Adegoke Adedapo Muritala ◽  
Dafe Aniekan Emiri
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Basalt Fiber ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Lightweight Aggregate Concrete ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Chopped Basalt Fiber

Relevance. The load on a reinforced concrete slab with high strength lightweight aggregate concrete leads to increased brittleness and contributes to large deflection or flexure of slabs. The addition of fibers to the concrete mix can improve its mechanical properties including flexure, deformation, toughness, ductility, and cracks. The aims of this work are to investigate the flexure and ductility of lightweight expanded clay concrete slabs reinforced with basalt fiber polymers, and to check the effects of basalt fiber mesh on the ductility and flexure. Methods. The ductility and flexural/deflection tests were done on nine engineered cementitious composite (expanded clay concrete) slabs with dimensions length 1500 mm, width 500 mm, thickness 65 mm. These nine slabs are divided in three reinforcement methods types: three lightweight expanded clay concrete slab reinforced with basalt rebars 10 mm (first slab type); three lightweight expanded clay concrete slab reinforced with basalt rebars 10 mm plus dispersed chopped basalt fiber plus basalt fiber polymer (mesh) of cells 2525 mm (second slab type); three lightweight expanded clay concrete slab reinforced with basalt rebars 10 mm plus dispersed basalt fiber of length 20 mm, diameter 15 m (third slab type). The results obtained showed physical deflection of the three types of slab with cracks. The maximum flexural load for first slab type is 16.2 KN with 8,075 mm deflection, second slab type is 24.7 KN with 17,26 mm deflection and third slab type 3 is 32 KN with 15,29 mm deflection. The ductility of the concrete slab improved with the addition of dispersed chopped basalt fiber and basalt mesh.

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