scholarly journals Effect of hybrid fibers, calcium carbonate whisker and coarse sand on mechanical properties of cement-based composites

2018 ◽  
Vol 68 (330) ◽  
pp. 156 ◽  
Author(s):  
M. Cao ◽  
L. Li ◽  
M. Khan
Keyword(s):  
Mechanical Properties ◽  
Calcium Carbonate ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Optimization Procedure ◽  
Coarse Sand ◽  
Flexural Behavior ◽  
Hybrid Fibers ◽  
Flexural Performance ◽  
Pva Fiber

Nowadays researchers are developing a new hybrid fiber reinforced cement-based composites (HyFRCC). The new HyFRCC can restrain micro-cracking, improves compressive and flexural performance of beams by addition of calcium carbonate (CaCO3) whisker, polyvinyl alcohol (PVA) fiber and steel fiber. In this work, a mix optimization procedure is shown for multi-scale HyFRCC, with steel, PVA fiber and CaCO3 whisker. The new HyFRCC is explored with addition of coarse sand to further improve its mechanical properties. Additionally, the flexural performance of beam and slabs has been investigated to optimize sand gradation and fiber combination in new HyFRCC. The compressive strength, flexural strength, flexural behavior, flexural toughness, equivalent flexural strength and deflection-hardening behavior of beams and slabs are improved with optimized content of sand gradation, fibers and CaCO3 whisker. The HyFRCC slab with 1.5% steel fiber, 0.4% PVA fiber, 1% CaCO3 whisker and optimized coarse sand showed overall best properties.

scholarly journals Effect of different PVA and steel fiber length and content on mechanical properties of CaCO3 whisker reinforced cementitious composites

2019 ◽  
Vol 69 (336) ◽  
pp. 200 ◽  
Author(s):  
M. Cao ◽  
C. Xie ◽  
L. Li ◽  
M. Khan
Keyword(s):  
Mechanical Properties ◽  
Crack Resistance ◽  
Fiber Length ◽  
Large Deflection ◽  
Steel Fiber ◽  
Flexural Behavior ◽  
Cementitious Composites ◽  
Hybrid Fiber ◽  
Pva Fiber ◽  
Fiber Reinforced Cementitious Composites

In this paper, calcium carbonate (CaCO3) whisker as a fiber reinforcement is mixed with steel and PVA fiber to form a multiscale hybrid fiber reinforced cementitious composites (MHFRCC). ASTM standard and post-crack strength techniques are performed to evaluate the mechanical properties of MHFRCC. The 1.25 % long steel fiber, 0.55 % short PVA fiber and 2.0 % CaCO3 whisker specimens showed the best flexural behavior before L/600 deflection. However, 1.5 % long steel fiber, 0.4 % long PVA fiber and 1.0 % CaCO3 whisker specimens presented better crack resistance after L/600 deflection. It is revealed that flexural parameters increase as comprehensive reinforcing index increase. The result showed that the CaCO3 whisker and short PVA fiber provided crack resistance effect at micro-scale and mainly play a dominate role in inhibiting micro-cracking. However, long steel fiber and long PVA fiber showed a better bridging effect of macro cracks at a large deflection.

scholarly journals Flexural Performance of Engineered Cementitious Compositelayered Reinforced Concrete Beams

2017 ◽  
Vol 63 (4) ◽  
pp. 173-189 ◽  
Author(s):  
A. R. Krishnaraja ◽  
S. Kandasamy
Keyword(s):  
Tensile Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Poly Vinyl Alcohol ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Strength ◽  
Flexural Performance ◽  
Pva Fiber

Abstract This study focuses to develop a new hybrid Engineered Cementitious Composite (ECC) and assesses the performance of a new hybrid ECC based on the steel short random fiber reinforcement. This hybrid ECC aims to improve the tensile strength of cementitious material and enhance better flexural performance in an RC beam. In this study, four different mixes have been investigated. ECC with Poly Vinyl Alcohol (PVA) fiber and PolyPropylene (PP) fiber of 2.0% volume fraction are the two Mono fiber mixes; ECC mix with PVA fiber of 0.65% volume fraction hybridized with steel fiber of 1.35% volume fraction, PP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction are the two additional different hybrid mixes. The material properties of mono fiber ECC with 2.0 % of PVA is kept as the reference mix in this study. The hybridization with fibers has a notable achievement on the uniaxial tensile strength, compressive strength, Young’s modulus, and flexural behavior in ECC layered RC beams. From the results, it has been observed that the mix with PVA fiber of 0.65% volume fraction hybrid with steel fiber of 1.35% volume fraction exhibit improvements in tensile strength, flexural strength, and energy absorption. The PP fiber of 0.65% volume fraction hybridized with steel of 1.35% volume fraction mix has reasonable flexural performance and notable achievement in displacement ductility over the reference mix.

scholarly journals Flexural Behavior of Reinforced Concrete Beams Reinforced with 3D-Textile Composite Fiber

2020 ◽  
Vol 26 (7) ◽  
pp. 127-144
Author(s):  
Mays R. Abdulghani ◽  
Dr. Ahmed S. Ali
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Main Idea ◽  
Composite Fiber ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Textile Fiber ◽  
Textile Composite

Normal concrete is weak against tensile strength, has low ductility, and also insignificant resistance to cracking. The addition of diverse types of fibers at specific proportions can enhance the mechanical properties as well as the durability of concrete. Discrete fiber commonly used, has many disadvantages such as balling the fiber, randomly distribution, and limitation of the Vf ratio used. Based on this vision, a new technic was discovered enhancing concrete by textile-fiber to avoid all the problems mentioned above. The main idea of this paper is the investigation of the mechanical properties of SCC, and SCM that cast with 3D AR-glass fabric having two different thicknesses (6, 10 mm), and different layers (1,2 layers). As well as micro-steel fiber with 1.25% volume fraction was used. Sixteen rectangular reinforced concrete beam specimens have been tested to study the behavior of their flexural strength. The results concluded that utilizing 3D-TFs with mortar mixture gave significantly higher enhancement for the load-carrying capacity than the concrete mixture. The utilization of 3D-TFs and micro-steel fiber together in the SCM mix gave better results. The stiffness of the specimens was improved with increasing the thickness and the number of textile fiber layers.

scholarly journals The effect of curing conditions on the mechanical properties of SIFCON

2021 ◽  
Vol 20 (1) ◽  
pp. 37-51
Author(s):  
Kubilay Akçaözoğlu ◽  
◽  
Adem Kıllı ◽  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Impact Resistance ◽  
Strength Properties ◽  
Fiber Reinforced Concrete ◽  
Curing Conditions ◽  
Accelerated Curing ◽  
Aspect Ratios ◽  
Curing Method

In this study, the effect of curing conditions on the mechanical properties of slurry infiltrated fiber reinforced concrete (SIFCON) was investigated. For this purpose, SIFCON samples containing 4% and 8% steel fiber with two different aspect ratios were produced. The samples were subjected to three different curing types, namely standard, dry and accelerated curing methods. Ultrasonic wave velocity, flexural strength, fracture toughness, compressive strength, impact resistance and capillary water absorption tests were performed on the samples. The highest flexural strength was found to be achieved in the samples with an aspect ratio of 55 and a content of 8% steel fiber. The most suitable curing method was determined as the standard curing method and the best flexural strength was achieved at the rate of 8%. According to the test results, the best strength properties were achieved in the samples exposed to the standard curing method. In addition, the samples exposed to the accelerated curing method showed satisfactory values. The accelerated curing method can be used as an alternative in SIFCON production especially in applications requiring mass production.

scholarly journals Study of Mechanical Properties of an Eco-Friendly Concrete Containing Recycled Carbon Fiber Reinforced Polymer and Recycled Aggregate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4592
Author(s):  
Chen Xiong ◽  
Tianhao Lan ◽  
Qiangsheng Li ◽  
Haodao Li ◽  
Wujian Long
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Fiber Reinforced Polymer ◽  
Recycled Aggregate ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Flexural Performance ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

This study investigates the feasibility of collaborative use of recycled carbon fiber reinforced polymer (RCFRP) fibers and recycled aggregate (RA) in concrete, which is called RCFRP fiber reinforced RA concrete (RFRAC). The mechanical properties of the composite were studied through experimental investigation, considering different RCFRP fiber contents (0%, 0.5%, 1.0%, and 1.5% by volume) and different RA replacement rates (0%, 10%, 20%, and 30% by volume). Specifically, ten different mixes were designed to explore the flowability and compressive and flexural strengths of the proposed composite. Experimental results indicated that the addition of RCFRP fibers and RA had a relatively small influence on the compressive strength of concrete (less than 5%). Moreover, the addition of RA slightly decreased the flexural strength of concrete, while the addition of RCFRP fibers could significantly improve the flexural performance. For example, the flexural strength of RA concrete with 1.5% RCFRP fiber addition increased by 32.7%. Considering the good flexural properties of the composite and its potential in reducing waste CFRP and construction solid waste, the proposed RFRAC is promising for use in civil concrete structures with high flexural performance requirements.

Study on the Preparation of Green and Environmentally Friendly High Toughness Cementitous Composites with Large Amount of Fly Ash

2020 ◽  
Vol 996 ◽  
pp. 97-103
Author(s):  
Xiang Rong Cai ◽  
Bai Quan Fu ◽  
Zhi Gang Liu
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Strain Hardening ◽  
Cementitious Composites ◽  
Special Focus ◽  
Type I ◽  
Flexural Performance ◽  
High Toughness ◽  
Four Point Bending ◽  
Pva Fiber

In order to reduce the environmental burden and the energy consumption of PVA fiber reinforced high toughness cementitious composites, special focus is placed on the influence of fly ash type and content and curing type on the flexural performance of high toughness cementitious composites through four-point bending tests. The high toughness cementitious composites without fly ash have been used in the program for comparison purpose. The tests results show that, compared with the basic high toughness cementitious composites, the flexural strength decreases and the deflection increases with the s/b increasing when the fly ash is added. The increase in fly ash content results in an improvement of strain hardening property and increases in both flexural strength and deflection, which show that fly ash is benefit to the pseudo strain hardening performance. However the effects of fly ash type and curing type are not obvious on the load but obvious on the deflection. The deflection of high toughness cementitious composites with type I fly ash or water curing is higher than that of type II or standard curing. It is demonstrated that all the high toughness cementitious composites studied in this paper exhibit strain-hardening and multiple cracking through adding fly ash.

scholarly journals Effects of Hooked-End Steel Fiber Geometry and Volume Fraction on the Flexural Behavior of Concrete Pedestrian Decks

2019 ◽  
Vol 9 (6) ◽  
pp. 1241 ◽  
Author(s):  
Seung-Jung Lee ◽  
Doo-Yeol Yoo ◽  
Do-Young Moon
Keyword(s):  
Flexural Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Three Dimensional ◽  
High Strength ◽  
Flexural Behavior ◽  
Multiple Cracks ◽  
Fiber Volume ◽  
Volume Fractions ◽  
Steel Rebars

This study investigates the effects of hooked-end fiber geometry and volume fraction on the flexural behavior of concrete pedestrian decks. To achieve this, three different fiber geometries, i.e., three-dimensional (3D), four-dimensional (4D), and five-dimensional (5D), and volume fractions of 0.37%, 0.6%, and 1.0% were considered. Test results indicate that a higher number of hook ends can more effectively enhance the flexural strength and flexural strength margin at all volume fractions than a lower number, so that the order of effectiveness of hooked-end fibers on the flexural strength parameters was as follows: 5D > 4D > 3D. To satisfy the ductility index of 0.39, the amounts of 3D, 4D, and 5D hooked steel fibers should be in the range of 0.98%‒1.10%. Moreover, at a fiber volume fraction of 1.0%, only multiple cracking behaviors were observed, and the numerical results indicated that the volume fraction should be equal to 1.0% to guarantee a deflection-hardening response of pedestrian decks, regardless of the hooked-end fiber geometry. Consequently, a 1.0% by volume of hooked-end steel fiber is recommended to replace the minimum longitudinal steel rebars and guarantee a ductile flexural behavior with multiple cracks for pedestrian decks made of high-strength concrete.

scholarly journals Mechanical properties of Hybrid steel/PVA fibers reinforced high strength concrete

2018 ◽  
Vol 199 ◽  
pp. 11005 ◽  
Author(s):  
Wasim Abbass ◽  
M. Iqbal Khan
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Research Work ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Hybrid Fiber ◽  
Strength Concrete ◽  
Flexural Performance ◽  
Micro Level

The high strength concrete exhibits improved compressive strength with drawback of brittle failure due to lack of tensile strength which can be catered by the addition of fibers. The efficient use of fibers with hybridization at macro and micro level can improve mechanical properties of high strength concrete. The effect of hybridization of hooked end steel macro fibers (60 mm) and PVA micro fibers (12 mm) with different dosages was investigated in this research work. The different percentage of steel and PVA were hybridized to find out the best combination of hybridized fibers in high strength concrete. The compressive and flexural properties of high strength concrete along with complete load vs deflection behaviour of hybrid fiber reinforced concrete were investigated. The results revealed that hybridization of macro and micro fibers provided better improvement in flexural performance. It was observed from the results that the hybrid combination of fibers of 1% macro steel fiber and 0.15% micro PVA fibers proved to be the best for enhancement in flexural performance of high strength concrete.

Investigation on Improvement of Flexural Behavior of Low-Density Cellular Concrete through Fiber Reinforcement for Non-Structural Applications

2019 ◽  
Vol 2673 (10) ◽  
pp. 641-651
Author(s):  
Arman Abdigaliyev ◽  
Jiong Hu
Keyword(s):  
Mechanical Properties ◽  
Lightweight Concrete ◽  
Construction Material ◽  
Flexural Behavior ◽  
Unit Weight ◽  
Slight Reduction ◽  
Low Density ◽  
Hybrid Fibers ◽  
Structural Applications ◽  
Cellular Concrete

During the last decades, cellular lightweight concrete (CLC), or foamed concrete, has been experiencing greater interest in geotechnical, structural, and non-structural applications. The low density and high flowability makes it a favorable construction material in relation to handling, placing, and construction costs. However, the applications of low-density cellular concrete (LDCC), the category of CLC with a unit weight less than 50 pounds per cubic foot (801 kg/m3) and generally without fine aggregates, are limited mostly to backfill applications in geotechnical engineering. The main reason lies in the brittleness of the material and low to zero resistance to flexural loads. Fiber-reinforced LDCC may be a reasonable solution to improve mechanical properties and expand the application range of the material. This study investigated the effects of adding polypropylene and hybrid fibers on physical and mechanical properties of LDCC and the feasibility of expanding LDCC utilization to non-structural applications. Results showed that although there is a slight reduction of flowability and compressive strength, the flexural behavior of LDCC can be significantly improved with the incorporation of fibers. The flexural strength and flexural toughness of LDCC was found to increase from 26.8 pounds per square inch (psi) (0.18 MPa) to 217.5 psi (1.48 MPa), and from 5.67 lb-in. (0.64 kN-mm) to 292 lb-in. (33.0 kN-mm) respectively at a 1.0% addition rate of a fibrillated polypropylene fiber selected in this study, which makes it a feasible material for non-structural applications.

scholarly journals Residual Flexural Performance of Epoxy Polymer Concrete under Hygrothermal Conditions and Ultraviolet Aging

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3472
Author(s):  
Ma ◽  
Pan ◽  
Liu ◽  
Jiang ◽  
Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Flexural Strength ◽  
Aging Time ◽  
Uv Radiation ◽  
Aging Process ◽  
Epoxy Polymer ◽  
Polymer Concrete ◽  
Flexural Performance ◽  
Layered Beam

Epoxy polymer concrete (EPC) has found increasing applications in infrastructure as a rising candidate among civil engineering materials. In most of its service environments, EPC is inevitably exposed to severe weather conditions, e.g., violent changes in temperature, rain, and ultraviolet (UV) radiation. In this paper, we designed an accelerated aging test for EPC, which includes periodic variation of temperature and water spray, as well as intensive UV-light irradiation, imitating the outdoor environment in South China. The experimental results show that the flexural performance of EPC is found deteriorate with the aging time. An aging process equivalent to four years (UV radiation dose) results in up to 8.4% reduction of flexural strength. To explore the mechanisms of observed performance degradation, the EPC specimen in the four-point-bending test is considered as a layered beam. The analysis indicates that the loss of flexural load-carrying capacity of an aged EPC beam is dominated by the reduction of mechanical properties of the surface layer. The mechanical properties of the surface layer are closely associated with the aging of epoxy mortar, which can be approximated as a reciprocal function of the aging time. By introducing damage to the surface layer into the layered beam, the proposed model demonstrates a good ability to predict the residual flexural strength of EPC during the aging process

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