Effect of hybrid polypropylene-steel fibres on strength characteristics of UHPFRC

Nuaklong, Peem,Chittanurak, Jithaporn,Jongvivatsakul, Pitcha,Pansuk, Withit,Lenwari, Akhrawat,Likitlersuang, Suched Techno-Press 2020 Advances in concrete construction Vol.10 No.1

This study intends to produce an ultra-high performance fibre reinforced concrete (UHPFRC) made with hybrid fibres (i.e., steel and polypropylene). Compressive and tensile strength characteristics of the hybrid fibres UHPFRC are considered. A total of 14 fibre-reinforced composites (FRCs) with different fibre contents or types of fibres were prepared and tested in order to determine a suitable hybrid fibre combination. The compressive and tensile strengths of each concrete at 7 days were determined. The results showed that a hybrid mix of micro-polypropylene and steel fibres exhibited good compromising performances and is the ideal reinforcement mixture in a strong, cost-effective UHPFRC. In addition, maximum compressive strength of 167 MPa was achieved for UHPFRC using 1.5% steel fibres blended with 0.5% macro-polypropylene fibres.

Investigating the Hybrid Effect of Micro-steel Fibres and Polypropylene Fibre-Reinforced Magnesium Phosphate Cement Mortar

Hu Feng,Qi Shao,Xupei Yao,Lulu Li,Chengfang Yuan 한국콘크리트학회 2022 International Journal of Concrete Structures and M Vol.16 No.5

To overcome the drawbacks caused by the intrinsic brittleness of cementitious materials, various types of fibres were incorporated as reinforcements. Extensive research on Ordinary Portland cement indicated that compared with the use of a single type of fibres, the mixed-use of multiple fibres can significantly improve both strength and toughness of the cementitious composites, which is referred to as the hybrid effect. However, such hybrid effect in multiple fibre-reinforced magnesium phosphate cement-based composite (HFRMC) still lack quantitative understanding. Therefore, this study conducted a series of experiments, including slump flow tests, compression tests, four-point bending tests and microstructure analysis, to investigate the hybrid effect of micro-steel fibres (MSF) and polypropylene (PP) fibres in HFRMC. Two types of mixed designs of HFRMC were conducted: 1. total fibres fraction (including both PP fibres and MSF) was fixed to be 1.6%; 2. PP fibres fraction was fixed to be 1.6% with different addition of MSF. Our results indicated that the slump flow of magnesium phosphate cement mortar varied around 7.6–8.8% with the hybrid use of MSF and PP fibres, while the flexural strength and toughness increased around 13.7–23.1% and 1.6–45.9%, respectively.

Crack Propagation Analysis of Synthetic vs. Steel vs. Hybrid Fibre-Reinforced Concrete Beams Using Digital Image Correlation Technique

Aniket B. Bhosale,S. Suriya Prakash 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.6

Improvement in fracture behaviour of fibre-reinforced concrete (FRC) due to the inclusion of various types and combinations of fibres is widely reported. The fracture behaviour of FRC needs to be fully understood for the optimum use of these fibres in structural elements. Fracture behaviours of synthetic fibre-reinforced concrete (SynFRC), hybrid fibre-reinforced concrete (HFRC) and steel fibre-reinforced concrete (SFRC) are investigated in this study using digital image correlation (DIC) technique. This work focuses on improvement in the structural performance of FRC through a comprehensive study of the change in the crack length, crack opening and fracture process zone (FPZ) due to different fibres addition and their combinations. Three distinct fibre dosages of 0.50%, 0.75%, and 1.00%, of macro-polyolefin fibres, hooked end steel fibres and their hybrid combination are regarded as research parameters. Test outcomes indicate that HFRC offers higher post-cracking resistance when compared to SynFRC. SFRC showcases superior fracture performance than that of HFRC and SynFRC. Full-field strain measurements from DIC are used to measure the crack openings at different load levels during the fracture tests. Results of DIC analysis show good agreement with experimental measurements. Continuous monitoring of strain contours using DIC reveals the effective engagement of fibres along the depth at higher dosages for HFRC when compared to that of SynFRC. Also, HFRC had longer cracks than SFRC at a particular load.

Experimental Study on Shear Behaviour of Hybrid Fibre Reinforced Concrete Beams

M. P. Karthik,D. Maruthachalam 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.1

In general Fibre Reinforced Concrete (FRC) can improve the strength properties of hardened concrete; likewise this experimentalinvestigation is to clarify Shear cracking behaviour of Hybrid Fibre Reinforced Concrete (HyFRC) beams, with the combination ofScrim bled Steel (ST) Fibre and synthetic fibre like Recycled Polyethylene Therephthalate (RPET) and Polypropylene (PP) in thevolume fraction of 0.5%. The grade of concrete is M40 was designed by using codal provision of IS 10262-2009. The mechanicalproperties and shear performance were studied for concrete prepared using different hybrid fibre combinations like ST-PP and STRPET. The dosage of fibres are 0-100, 25-75, 50-50, 75-25, 100-25. Addition of steel fibres generally contributed towards bridgingaction where as synthetic fibres resulted in delaying formation of the micro cracks. Compared to the ST-RPET combination, the shearperformance of the hybrid fibre reinforced concrete is superior in ST-PP combination. Then the experimental results were exploredwith the nonlinear Finite Element Analysis (FEA) using ANSYS 12 that has been carried out to simulate the behaviour of failuremodes of HyFRC beams. The result shows that the combination of ST-PP is relatively similar with the experimental investigation. The maximum result obtain in combination of ST75PP25 combination, Allowable strength of the Polyethylene Theraphthalte fibre iscomparatively lower than the Steel and Polypropylene fibre.

Study of Mechanical and Thermomechanical Properties of Vinyl Ester/Polyurethane Interpenetrating Polymer Network Based Hybrid Composites

Sudipta Goswami,Jagesh Kumar Ranjan 한국섬유공학회 2020 Fibers and polymers Vol.21 No.5

Interpenetrating polymer networks of vinyl ester (VE) resin and polyurethane (PU) was synthesized using blendratio of 93:7 (w/w). Bio-composites with Kenaf fibre reinforcement in VE/PU IPN matrix were prepared by hand-lay-up. Similar bio-composites were prepared with vinyl silane treated kenaf (SKF) and fibre content was varied by 15, 25, 35 and40 wt. % of the matrix in both the cases. Hybrid composites consisting of both silica nano filler (2 wt. %) and 35 % of kenaffibre together in VE/PU IPN (93:7 w/w) matrix were prepared. Analysis of these composites showed that 93VESi35SKFhybrid composite possessed improved tensile strength, Young’s modulus and Interlaminar Shear Strength by 3.12, 0.24 %and 4.13 % respectively in comparison to that of the 93VESi35KF. Thus silane treatment of natural fibre caused better fibre/matrix adhesion in these hybrid composites. Also the same properties increased by 9.22, 18.53 and 22.07 % respectively for93VESi35SKF in comparison to that of 93VE35KF showing that the hybrid composite was stronger than the correspondingbio-composite without nanofiller.

Flexural Mechanical Properties of Natural Fibre Reinforced Polymer Composites - A Statistical Investigation

Benkhelladi Asma,Laouici Hamdi,Bouchoucha Ali,Mouadji Youcef 한국섬유공학회 2020 Fibers and polymers Vol.21 No.10

The objectives and novelty of this paper are to create a hybrid-natural fibre composite by the Response SurfaceMethodology RMS technique, and then compared this hybrid composite with the individual fibre reinforced composites inthe bending test. The first aim of this study is devoted to analyse, modelize and optimise the various independent variablessuch as the type of fibres (X1), the types of chemical treatment (X2), the volume fraction of fibre (X3) and the treatmentduration (X4) used on the output parameters which are the mechanical characteristics namely, ultimate flexural stress andflexural modulus in the bending test using a Box-Behnken experimental design. Mathematical models for ultimate flexuralstrength and flexural modulus were developed using the response surface methodology (RSM). These models would behelpful in selecting independent variables in order to maximize the flexural mechanical properties. Statistical analysis of theresults showed that selected variables had a significant effect on the flexural properties, except the treatment time that has avery weak significance effect on the flexural properties. In the second section, the impact behaviors of the natural hybridcomposites found by the RMS method were confirmed experimentally. Finally, the experimental results indicate that theflexural properties of the natural hybrid composites increase with an increase in the composition of jute fibres.

Prediction of Hybrid fibre-added concrete strength using artificial neural networks

Ali Demir 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.4

Fibre-added concretes are frequently used in large site applications such as slab and airports as well as in bearing system elements or prefabricated elements. It is very difficult to determine the mechanical properties of the fibre-added concretes by experimental methods in situ. The purpose of this study is to develop an artificial neural network (ANN) model in order to predict the compressive and bending strengths of hybrid fibre-added and non-added concretes. The strengths have been predicted by means of the data that has been obtained from destructive (DT) and non-destructive tests (NDT) on the samples. NDTs are ultrasonic pulse velocity (UPV) and Rebound Hammer Tests (RH). 105 pieces of cylinder samples with a dimension of 150 × 300 mm, 105 pieces of bending samples with a dimension of 100x100x400 mm have been manufactured. The first set has been manufactured without fibre addition, the second set with the addition of %0.5 polypropylene and %0.5 steel fibre in terms of volume, and the third set with the addition of %0.5 polypropylene, %1 steel fibre. The water/cement (w/c) ratio of samples parametrically varies between 0.3-0.9. The experimentally measured compressive and bending strengths have been compared with predicted results by use of ANN method.

Bioinspired Hard–Soft Interface Management for Superior Performance in Carbon Fibre Composites

Ben Newman,James D. Randall,Russell J. Varley,Filip Stojcevski,Luke C. Henderson 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

Nature has evolved to create materials of unmatched performance governed by the interfacial interactions between hard and soft surfaces. Typically, in a carbon fibre composite, one polymer and one type of carbon fibre is used throughout a laminate. In this work, we use a carbon fibre surface modification approach to vary the fibre–matrix interface throughout the laminate to tailor the soft–hard interfaces. We demonstrate this effect using reclaimed carbon fibre materials in a thermoset polymer, then extend this concept to a thermoplastic polymer matrix–polypropylene. The thermoset specimens examined in this work consist of 5 carbon fibre plies, featuring 0, 1, 3 or 5 surface-modified layers located at the centre of the composite. The largest improvements in physical properties for these composites (yield strength, ultimate flexural strength, and tensile modulus) were found when only 1 modified layer of carbon fibre was placed directly within the centre of the composite. Subsequent investigations revealed that for a polypropylene matrix, where the surface chemistry is tailored specifically for polypropylene, improvements are also observed when mixed surface chemistries are used. This work shows that surface modification of reclaimed carbon fibres as non-woven mats can provide significant improvements in mechanical properties performance for structural composites when used in strategically advantageous locations throughout the composite.

Hybrid Polyester Composites Reinforced with Curauá Fibres and Nanoclays

Gilberto García del Pino,Antonio Claudio Kieling,Abderrezak Bezazi,Haithem Boumediri,Juliana Fontolan Rolim de Souza,Francisco Valenzuela Díaz,Jose Luis Valin Rivera,Jamile Dehaini,Tulio Hallak Panzer 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2

This work investigates a hybrid polyester composite consisted of Curauá natural fibres and organophilic clay nanoparticles. A Taguchi method is used to identify the effects of fibre fraction (10, 20 and 30 wt%), alkaline treatmentconcentration (NaOH, 2.5, 5 and 10 wt%), treatment time (2, 4 and 8 h) and nanoparticle content (2.5, 5 and 10 wt%) on the mechanical behaviour of the hybrid composites under tension and three-point bending. X-ray, FTIR and microstructural analysis are performed to assess the treated and untreated fibre surfaces. The optimum combination of the process parameters for the tensile and flexural properties is: fibre content at 30 wt%, NaOH concentration at 5 wt%, treatment time at 8 h and nanoclay inclusions at 5 wt%. A mean tensile and flexural strength of 36.13 MPa and 32.55 MPa are obtained, whichrepresents percent increases of 39.22 % and 25.43 % compared to the polyester polymer in pristine condition.

TENSILE, FLEXURAL PROPERTIES OF WOVEN JUTE/GLASS AND JUTE/SILK HYBRID COMPOSITES

P. Noorunnisa Khanam,Chi Hoon Jeon,Pham Thanh Nhut,Young Jin Yum 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

Unsaturated polyester based woven jute/glass and woven jute/silk fibre hybrid composites were prepared by hand layup method. Mechanical properties like tensile and flexural properties were studied for these hybrid composites. Tensile and flexural properties were also studied for woven jute, woven silk fibre composites and also for matrix. The results of jute/glass and jute/silk composites were compared with the results of jute/silk hybrid composites. From the results, it was observed that jute/glass hybrid composites showed better properties than jute/silk fibre reinforced hybrid composites. It was also observed that jute fibre properties were improved by adding glass and silk fibre in hybrid composites. Mechanical tests were carried out by using ASTM methods.