Bonding Strength of Expanded Polystyrene (EPS) Beads Enhanced with Steel Fiber in Reinforced Lightweight Concrete (LWC)

2014 ◽  
Vol 661 ◽  
pp. 100-105 ◽  
Author(s):  
Jamilah Abd. Rahim ◽  
Siti Hawa Hamzah ◽  
Mohd Saman Hamidah
Keyword(s):  
Aspect Ratio ◽  
Bonding Strength ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Expanded Polystyrene ◽  
Normal Concrete ◽  
Pull Out ◽  
Concrete Mix ◽  
Reinforcement Bar

Lightweight concrete (LWC) is one of the favourable concrete to be used as it has low density with acceptable high strength, high durability, and toughness. In order to produce LWC, it is required special material such as expanded polystyrene (EPS) beads and steel fiber to be added into the design mix concrete. As known, EPS beads have zero strength. Meanwhile, the significant of steel fiber is to reduce micro and macro crack propagation. Therefore, pull out test were carried out to measure the bond strength between reinforcement bar and three series of concrete mix design which are normal concrete, EPS-LWC and EPS-LWC enhanced with steel fiber. Concrete adhesion and bearing deformation of reinforcing bar against the concrete are the two main mechanisms that influence the strength of bond in the steel reinforced concrete. Deformation will increase when the bonding stress increase. Normal concrete series shows the higher average bonding stress which is 531.22 kPa compared to others series concrete mix. Meanwhile, bonding stress of EPS-LWC mix is 174.54 kPa which is higher than EPS-LWC enhanced with steel fiber mix. Even though the present of the steel fibre can increase the strength of the LWC, but it effects to the bonding strength between reinforcement steel rod and concrete. There are two improtant factor in bonding determination which are volume fraction and aspect ratio of the steel fiber. Segregation will increase when the aspect ratio of steel fiber increased. Besides, the workability becomes low. This present study used types of hooked end steel fiber with 60 mm length and aspected ratio is 0.75. While the size of the cylindrical is 300 mm x 150 mm. The position of the steel fiber in the specimens is too compact and presenting the air voids. Consequently weaken the bonding strength between concrete and reinforcement bar.

Study on the In Situ Growth of Carbon Nanotubes for the Reinforcement of Cf/SiC Composite Fabricated by CVI+PIP Process

2013 ◽  
Vol 745-746 ◽  
pp. 582-586 ◽  
Author(s):  
Jian Bao Hu ◽  
Shao Ming Dong ◽  
Xiang Yu Zhang ◽  
Zhen Wang ◽  
Hai Jun Zhou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Bonding Strength ◽  
Volume Fraction ◽  
Interfacial Bonding ◽  
Mechanical And Thermal Properties ◽  
Fiber Volume ◽  
Pull Out ◽  
Interfacial Bonding Strength

Cf/SiC composites were fabricated through in situ growth of carbon nanotubes (CNTs) on three-dimensional needle-punched carbon fabric via chemical vapor deposition and polymer impregnation and pyrolysis process. The mechanical and thermal properties of the composites were investigated. The flexural strength and fracture toughness were decreased due to the fiber volume fraction loss and much shorter pull-out length of fibers which was caused by the higher interfacial bonding strength between fiber and matrix after the growth of CNTs. Brittle fracture character of CNTs was observed due to the strong interfacial bonding strength between CNTs and matrix. The parallel thermal conductivity and perpendicular thermal conductivity were improved to 14.5% and 8.0% respectively.

scholarly journals Flexural Fatigue Performance of Steel Fiber Reinforced Expanded-Shales Lightweight Concrete Superposed Beams with Initial Static-Load Cracks

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3261
Author(s):  
Fulai Qu ◽  
Changyong Li ◽  
Chao Peng ◽  
Xinxin Ding ◽  
Xiaowu Hu ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Static Load ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Stress Amplitude ◽  
Flexural Stiffness ◽  
Compression Zone ◽  
Fatigue Load ◽  
Upper Limit

Concerning the structural applications of steel fiber reinforced expanded-shales lightweight concrete (SFRELC), the present study focuses on the flexural fatigue performance of SFRELC superposed beams with initial static-load cracks. Nine SFRELC superposed beams were fabricated with the SFRELC depth varying from 50% to 70% of the whole sectional depth, and the volume fraction of steel fiber ranged from 0.8% to 1.6%. The fatigue load exerted on the beams was a constant amplitude sinusoid with a frequency of 10 Hz and a fatigue characteristic value of 0.10; the upper limit was taken as the load corresponded to the maximum crack width of 0.20 mm at the barycenter of the longitudinal rebars. The results showed that with the increase of SFRELC depth and the volume fraction of steel fiber, the fatigue life of the test beams was prolonged with three altered failure modes due to the crush of conventional concrete in the compression zone and/or the fracture of the tensile rebar; the failure pattern could be more ductile by the prevention of fatigue fracture by the longitudinal tensile rebar when the volume fraction of steel fiber was 1.6% and the reduction of crack growth and concrete strain in the compression zone; the fatigue life of test beams was sensitive to the upper-limit of the fatigue load, a short fatigue life appeared from the higher stress level and larger stress amplitude of the longitudinal rebar due to the higher upper-limit of the fatigue load. The methods for predicting the stress level, the stress amplitude of the longitudinal tensile rebar, and the degenerated flexural stiffness of SFRELC superposed beams with fatigue life are proposed. With the optimal composites of the SFRELC depth ratio and the volume fraction of steel fiber, the controllable failure of reinforced SFRELC superposed beams could be a good prospect with the trend curves of fatigue flexural stiffness.

scholarly journals Influence of MgO and Hybrid Fiber on the Bonding Strength between Reactive Powder Concrete and Old Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Mo Jinchuan ◽  
Ou Zhongwen ◽  
Wang Yahui
Keyword(s):  
Tensile Strength ◽  
Bonding Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Drying Shrinkage ◽  
Splitting Tensile Strength ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Reactive Powder

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.

Experimental Study on Shear Behavior of Hybrid Fiber Reinforced High Performance Concrete Deep Beams

2012 ◽  
Vol 166-169 ◽  
pp. 664-669
Author(s):  
Sheng Bing Liu ◽  
Lihua Xu
Keyword(s):  
Shear Strength ◽  
Aspect Ratio ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Shear Behavior ◽  
Calculation Formula ◽  
Hybrid Fiber ◽  
Deep Beams ◽  
Vertical Reinforcement

In order to investigate the effect of steel fiber and polypropylene fiber on shear behavior of HPC deep beams, the shear tests were conducted on 18 different groups of deep beams with steel fiber and polypropylene fiber and 2 groups of HPC deep beams without fiber according to the orthogonal experiment. 6 factors, including the shape of steel fiber, the volume fraction of steel fiber, the aspect ratio of steel fiber, the volume fraction of polypropylene fiber, the ratio of web horizontal reinforcement and the ratio of web vertical reinforcement, were compared by direct-viewing analysis. Results illuminate that hybrid fibers greatly increase the diagonal cracking strength and shear strength of HPC deep beams. The aspect ratio of steel fiber plays the most important role in diagonal cracking strength whereas the ratio of web vertical reinforcement has minimum effect. Meanwhile the ratio of web horizontal reinforcement plays the most important role in shear strength whereas the volume fraction of polypropylene fiber has minimum effect. An anti-cracking capacity for inclined section calculation formula and a shear bearing capacity calculation formula for hybrid fiber reinforced HPC deep beams are put forward based on current code. Meantime test verification is carried out and the calculated results are satisfied.

scholarly journals Compressive strength of lightweight expanded polystyrene basalt fiber concrete

2020 ◽  
Vol 329 ◽  
pp. 04010
Author(s):  
Galina Okolnikova ◽  
Lina Abass Saad ◽  
Majeed M. Haidar ◽  
Fouad adnan noman Abdullah Al-shaibani
Keyword(s):  
Compressive Strength ◽  
Lightweight Concrete ◽  
Polypropylene Fiber ◽  
Basalt Fiber ◽  
Expanded Polystyrene ◽  
Noticeable Effect ◽  
Lower Weight ◽  
Fiber Concrete ◽  
Concrete Mix ◽  
Research Show

The ability of concrete to give a lower weight and retain good properties for strength is very important concrete structures. Lightweight concrete is known for its brittleness hence the strengthening of the concrete with dispersed chopped fiber is necessary. The addition of dispersed chopped fiber in polystyrene concrete to check the effect of the fiber this concrete the main objective of this paper. The experimental method of research was used in this research paper after a proper review of previous works by other researchers were done. 42 grams of fiber were added in the concrete mix of each composition. The results of this research show a noticeable effect of fiber in the lightweight expanded polystyrene concrete. The concrete without fiber showed the best compressive strength followed by the concrete with dispersed polypropylene fiber.

scholarly journals Development of Steel Fiber-Reinforced Expanded-Shale Lightweight Concrete with High Freeze-Thaw Resistance

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Mingshuang Zhao ◽  
Xiaoyan Zhang ◽  
Wenhui Song ◽  
Changyong Li ◽  
Shunbo Zhao
Keyword(s):  
Steel Fiber ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
Content Volume ◽  
Steel Fibers ◽  
Fine Aggregate ◽  
Test Results ◽  
Fiber Reinforced ◽  
Freeze Thaw ◽  
Expanded Shale

For the popularized structural application, steel fiber-reinforced expanded-shale lightweight concrete (SFRELC) with high freeze-thaw resistance was developed. The experimental study of this paper figured out the effects of air-entraining content, volume fraction of steel fibers, and fine aggregate type. Results showed that while the less change of mass loss rate was taken place for SFRELC after 300 freeze-thaw cycles, the relative dynamic modulus of elasticity and the relative flexural strength presented clear trends of freeze-thaw resistance of SFRELC. The compound effect of the air-entraining agent and the steel fibers was found to support the SFRELC with high freeze-thaw resistance, and the mechanisms were explored with the aid of the test results of water penetration of SFRELC. The beneficial effect was appeared from the replacement of lightweight sand with manufactured sand. Based on the test results, suggestions are given out for the optimal mix proportion of SFRELC to satisfy the durability requirement of freeze-thaw resistance.

scholarly journals Effect of Using EVA as Partial Replacement for Coarse Aggregates on Concrete Properties

2021 ◽  
Vol 9 (2) ◽  
pp. 58-63
Author(s):  
Moatasim Attaelmanan Alnour Mustafa ◽  
Mohammed Izzeldeen Mansour Ibrahim ◽  
Mohammed Tawfeeg Mohammed Alradey ◽  
Mohammed Altayeb Berier Alsheikh
Keyword(s):  
Vinyl Acetate ◽  
Lightweight Concrete ◽  
Ethylene Vinyl Acetate ◽  
Weight Percent ◽  
Partial Replacement ◽  
Standard Mixture ◽  
Normal Concrete ◽  
Suitable Material ◽  
Coarse Aggregates ◽  
Concrete Mix

Ethylene-vinyl acetate (EVA), is the copolymer of ethylene and vinyl acetate. The weight percent of vinyl acetate usually varies from 10 to 40%, with the residuum being ethylene, also EVA is an elastomeric polymer that makes materials which are (rubber-like) in fineness and flexibility. In this study, EVA waste was used in the concrete mix instead of different percentages of coarse aggregates (5%, 8%, 10%, 12%) by volume. The concrete slump test was performed to measure the workability of freshly made concrete. The compression test was performed on all samples at 7 and 28 days. The results were compared with the standard mixture. It was concluded that EVA was a suitable material to replace coarse aggregates. Accordingly, the results of these experiments indicate that not only EVA can be noticed as aggregate in concrete, but also it will have more advantages in lightweight concrete than normal concrete. Using of EVA concrete shows decrease in slump for further replacement without compromising on strength. The best replacing ratio was 5% of aggregate.  

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