scholarly journals Study on Mechanical Properties of Hybrid Polypropylene-Steel Fiber RPC and Computational Method of Fiber Content

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2243
Author(s):  
Chunling Zhong ◽  
Mo Liu ◽  
Yunlong Zhang ◽  
Jing Wang ◽  
Dong Liang ◽  
...  

On the basis of determining the optimum content of polypropylene fiber reactive powder concrete (RPC), the influence of different steel fiber content on the compressive strength and splitting tensile strength of hybrid polypropylene-steel fiber RPC was studied. The particle morphology and pore parameters of hybrid polypropylene-steel fiber RPC were analyzed by combining scanning electron microscope (SEM) with image-pro plus (IPP) software. The results showed that the RPC ductility can be further improved on the basis of polypropylene fiber RPC, the compressive strength and splitting tensile strength of polypropylene fiber. The optimum content of hybrid polypropylene-steel fiber RPC is 0.15% polypropylene fiber, 1.75% steel fiber. Hybrid polypropylene-steel fiber RPC is mainly composed of particles with small particle size. The particle area ratio first increased and decreased with the increase of steel fiber content, and the maximum steel fiber content is 1.75%. The pore area ratio first decreased and increased with the increase of steel fiber content, and the pore area ratio is the smallest when the steel fiber content is 1.75%. The calculation methods of polypropylene fiber content and steel fiber content and 28-day RPC compressive strength and splitting tensile strength are proposed to select polypropylene fiber content and steel fiber content flexibly according to different engineering requirements, which can provide important guidance for the popularization and application of RPC in practical engineering.

2011 ◽  
Vol 477 ◽  
pp. 274-279 ◽  
Author(s):  
Yi Xu ◽  
Lin Hua Jiang ◽  
Hong Qiang Chu ◽  
Lei Chen

In this study, the effects of fiber types on the mechanical properties of lightweight aggregate concretes were investigated. Three types of fibers, namely, polypropylene fiber, steel fiber and water hyacinth (Eichhornia crassipes) fiber, and two types of lightweight aggregates, namely, expanded polystyrene and ceramsite were used. The compressive strength and splitting tensile strength of concretes were tested. The results show that both the compressive strength and the splitting tensile strength were improved by adding a reasonable volume of steel fiber and polypropylene fiber into LWAC. The addition of water hyacinth fiber had little effect on the compressive strength of LWAC, while a little increase was observed in the splitting tensile strength.


2014 ◽  
Vol 906 ◽  
pp. 329-334
Author(s):  
Yu Ting Zhu ◽  
Dong Tao Xia ◽  
Bo Ru Zhou

In this paper, according to the national standard and testing methods,the direct tension strength,splitting tensile strength and cubic compressive strength test were carried out for 8 different groups of hybrid fiber (containing steel fiber, macro-polypropylene fiber and dura fiber) reinforced HPC specimens.The results showed that when the volume proportion of ternary hybrid fiber was less than 1%, there was not obvious influence for the concrete compressive strength, but the splitting tensile strength increased by 26% ~ 69%; the ratio between splitting tensile strength and compressive strength for HFRC increased to 1/12~1/9. When added 0.7% steel fiber, 0.19% macro-polypropylene fiber and 0.11% dura fiber, the confounding effect was the best. Based on the advantages and disadvantages of tensile splitting strength and direct tensile strength test and the results of tests, the concept of equivalent tensile strength and calculative formula was put forward .


YMER Digital ◽  
2021 ◽  
Vol 20 (11) ◽  
pp. 421-430
Author(s):  
M. Sriram ◽  
◽  
K.R. Aswin Sidhaarth ◽  
◽  
◽  
...  

Increasing demand and inadequate materials availability leads the researchers to find alternate materials. In general, hybrid fiber is nothing but mixture of two or more fibers. In this review, various properties of steel fibers and polypropylene fibers were studied. In order to study the physical and mechanical properties of steel fiber, polypropylene fiber and other materials used in concrete, various tests such as Slump cone test, Compaction factor, Compressive strength , flexural strength etc., were used. Hybrid fibers have the tendency to control cracks at different levels. Workability of concrete get reduced due to more addition of steel fibers.The addition of steel fiber and polypropylene fiber results in an increase of 12 to 14.30% compressive strength, 33 to 36.6% increase in flexural strength and 9 to 10.16% increase in split tensile strength. Addition of most favorable amount 0.9 to 1% of steel fiber and 0.9 to 1% of polypropylene fiber gives maximum compressive strength up to 41.67 to 42.68%. Split tensile strength increases by increasing the fiber content in concrete but workability decreases when steel fiber content is increased in concrete.


2014 ◽  
Vol 1065-1069 ◽  
pp. 1985-1989
Author(s):  
Jia Bin Wang ◽  
Di Tao Niu ◽  
Rui Ma ◽  
Ze Long Mi

In order to investigate the carbonation resistance of shotcrete and the mechanical properties after carbonation, the accelerated carbonation test was carried out. The results indicate that the carbonation resistance of shotcrete is superior to that of normal concrete. With the increasing of carbonation depth, compressive strength and splitting tensile strength of shotcrete grew rapidly. The admixing of steel fiber can further improve the carbonation resistance, reduce the carbonation rate, and increase the splitting tensile strength of shotcrete greatly. Besides, based on analyzing the effects of construction technology and steel fiber of concrete for the carbonation resistance, a carbonation depth model for shotcrete was established. Key words: shotcrete; carbonation; steel fiber; mechanical properties


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Mo Jinchuan ◽  
Ou Zhongwen ◽  
Wang Yahui

The reactive powder concrete (RPC) was used as concrete repair material in this paper. The influence of steel fiber, steel fiber + MgO, and steel fiber + MgO + polypropylene fiber (PPF) on the mechanical properties of RPC repair materials and the splitting tensile strength between RPC and old concrete was studied. Influences of steel fiber, MgO, and PPF on the splitting tensile strength were further examined by using scanning electronic microscopy (SEM) and drying shrinkage test. Results indicated that the compressive and flexural strength was improved with the increasing of steel fiber volume fraction. However, the bonding strength showed a trend from rise to decline with the increasing of steel fiber volume fraction. Although MgO caused mechanical performance degradation of RPC, it improved bonding strength between RPC and existing concrete. The influence of PPF on the mechanical properties of RPC was not obvious, whereas it further improved bonding strength by significantly reducing the early age shrinkage of RPC. Finally, the relationship of drying shrinkage and splitting tensile strength was studied, and the equation between the splitting tensile strength relative index and logarithm of drying shrinkage was obtained by function fitting.


2010 ◽  
Vol 34-35 ◽  
pp. 1441-1444 ◽  
Author(s):  
Ju Zhang ◽  
Chang Wang Yan ◽  
Jin Qing Jia

This paper investigates the compressive strength and splitting tensile strength of ultra high strength concrete containing steel fiber. The steel fibers were added at the volume fractions of 0%, 0.5%, 0.75%, 1.0% and 1.5%. The compressive strength of the steel fiber reinforced ultra high strength concrete (SFRC) reached a maximum at 0.75% volume fraction, being a 15.5% improvement over the UHSC. The splitting tensile strength of the SFRC improved with increasing the volume fraction, achieving 91.9% improvements at 1.5% volume fraction. Strength models were established to predict the compressive and splitting tensile strengths of the SFRC. The models give predictions matching the measurements. Conclusions can be drawn that the marked brittleness with low tensile strength and strain capacities of ultra high strength concrete (UHSC) can be overcome by the addition of steel fibers.


2011 ◽  
Vol 413 ◽  
pp. 270-276 ◽  
Author(s):  
Wen Zhong Zheng ◽  
Hai Yan Li ◽  
Ying Wang ◽  
Heng Yan Xie

87 prismatic flexural steel fiber-reinforced reactive powder concrete (RPC) specimens with the size of 40mm×40mm×160mm were tested as well as 87 dumbbell-shaped axis tensile RPC specimens after being exposed to different high temperatures. The effect of steel fiber content and heating temperature on the flexural and tensile strength of steel fiber-reinforced RPC was analyzed. With the steel fiber content increasing, the flexural and tensile strength of steel fiber-reinforced RPC after high temperature improve significantly, and they increase first and then decrease with the heating temperature elevated, and the critical temperatures are 200¡æ and 120¡æ, respectively. Equations are established to express the relationship between the flexural and tensile strength of steel fiber-reinforced RPC and the heating temperature. The theoretical curves are in good agreement with the test data.


In this paper various mix proportions of Reactive Powder Concretes were formulated using ordinary Portland cement, Fly ash, Micro silica, Silica Fume, Quartz powder etc and these concretes were subjected to strength test. The best mix was selected for further in depth study with fibers like Sisal fiber, Coir fiber, Hair fiber and Polypropylene fiber mixed Reactive Powder Concrete and the various tests have been performed Cube Compressive strength, Cylinder Compressive strength, Flexural strength, Split Tensile strength, Shear test, Water absorption, Sorptivity and Chloride diffusion etc. As a result, fiber incorporated concrete shows increasing Flexural strength, splitting tensile strength, and shear strength up to 30% as compared to control RPC and gives minimal decrease in compressive strength by the addition of fibers. These characteristics make it as a promising material for casting non structural elements such as pressure pipes, flooring tiles, Partition panels, door and window frames. It can also be used as repair materials.


Author(s):  
Asfaw Mekonnen LAKEW ◽  
Mukhallad M. AL-MASHHADANI ◽  
Orhan CANPOLAT

This experimental work evaluated geopolymer concrete containing fly ash and slag by partial replacement of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) to manufacture environmental-friendly concrete. The proportion of recycled aggregates considered consists of 10%, 20%, 30%, and 40% of the total coarse aggregate amount. Also, a steel fiber ratio of 0.3% was utilized. The mechanical properties and abrasion resistance of fly ash/slag-based geopolymer concrete were then assessed. Majorly, the mechanical strength of the concrete samples decreased by the increase of RCA content. The geopolymer concrete with 40% RCA gave 28.3% lesser compressive strength and 24% lower splitting tensile strength than NCA concrete at one year. Also, the flexural strength of concrete specimens was reduced by 35% (from 5.34MPa to 3.5MPa) with the incorporation of 40% RCA. The incorporation of 30% RCA caused 23% and 22.6% reduction in compressive strength at 56 days and one year, respectively. The flexural and splitting tensile strength of the specimens was not significantly reduced (less than 10%) with the inclusion of a recycled coarse aggregate ratio of up to 30%. Furthermore, the abrasion wear thickness of every concrete sample was less than 1mm. RCA inclusion of 20% produced either insignificant reduction or better strength results compared to reference mixtures. As a result, it was considered that the combination of 0.3% steel fiber and 20% recycled coarse aggregate in fly ash/slag-based geopolymer concrete leads to an eco-friendly concrete mix with acceptable short and long-term engineering properties that would lead to sustainability in concrete production and utilization sector.


2019 ◽  
Vol 9 (8) ◽  
pp. 1602 ◽  
Author(s):  
Ditao Niu ◽  
Daguan Huang ◽  
Hao Zheng ◽  
Li Su ◽  
Qiang Fu ◽  
...  

This study investigates the effects of basalt–polypropylene fibers on the compressive strength and splitting tensile strength of concrete and calculates the fractal dimension of the pore structure of concrete by using a fractal model based on the optical method. Test results reveal that hybrid fibers can improve the compressive strength and splitting tensile strength of concrete, and the synergistic effect of the hybrid fibers is strongest when the contents of basalt fiber (BF) and polypropylene fiber (PF) are 0.05% each, and that the maximum increments in compressive strength and splitting tensile strength are 5.06% and 9.56%, respectively. The effect of hybrid fibers on splitting tensile strength is greater than on compressive strength. However, hybrid fibers have adverse effects on mechanical properties when the fiber content is too high. The pore structure of basalt–polypropylene fiber-reinforced concrete (BPFRC) exhibits obvious fractal characteristics, and the fractal dimension is calculated to be in the range of 2.297–2.482. The fractal dimension has a strong correlation with the air content and spacing factor: the air content decreases significantly whereas the spacing factor increases with increasing fractal dimension. In addition, the fractal dimension also has a strong positive correlation with compressive strength and splitting tensile strength. Therefore, the fractal dimension of the pore structure can be used to evaluate the microscopic pore structure of concrete and can also reflect the influence of the complexity of the pore structure on the macroscopic mechanical properties of concrete.


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