It is evident from Table 4 that the hybridfibrereinforcedconcrete specimens exhibit more number of cracks with lesser widths when compared to the plain concrete. The percentage reduction was of the order of 61.3% when compared to the plain concrete. Table 4 indicates that the hybridfibrereinforcedconcrete specimens exhibit enhanced ductility than that of plain concrete. It was noticed that for specimens with fibres the failure was not sudden. The randomly oriented fibres crossing the cracked section resisted the propagation of cracks and separation of the section. This caused an increase in the load carrying capacity beyond the first cracking 9-11 . The increase in
ABSTRACT: An experimentalinvestigation was made by the partial replacement of fine aggregates with hemp and steel fibres in concrete. HybridFibreReinforcedConcrete (HFRC) can be defined as concrete that is reinforced by two or more types of fibres. Partial replacement was done for mono fibre(hemp) and hybridfibre (hemp and steel) concrete. The above fibres were cut into fine pieces. Steel and hemp fibres were partially replaced by the weight of cement in various proportions of 0.5%,1%,1.5% respectively in the concrete mixture. Concrete having compressive strength of 25 N/mm 2 (M25) was used. Test were carried out for each mix in fresh state to test the workability of concrete. In addition, compressive strength, flexure strength and split tensile strength were carried out and compared with conventional concrete. The test conducted reveals that mono fibres(hemp) shows higher strength when compared with hybrid and conventional concrete in compressive and flexural nature but decreases in tensile nature.
An experimental research has been planned to study the behavior of short columns having 150 mm×150 mm×700 mm size in-filled with different types of concrete such as normal M30 mix and hybrid fiber reinforcedconcrete (HFRC). To obtain suitable hybrid fiber reinforcedconcrete mix for columns several trials was done by standard compression test, flexural test and slit tensile test on cube, beam and cylinder. From the test results the optimum dosages of different fibers was determined. Details of column specimens were given in table 6.
From Fig 4, Acid attack test is having more strength on 1.0% fibers+ 15% silica fume and quartz powder. In this Acid Attack Test strength at 56 days increases 13.86 % for HF2 and 17.35% for M2 when compared with conventional concrete. The loss of strength is 6.49% for CM, 5.30% for HF2 and 5.56% for M2. In this Acid Attack Test strength at 90 days increases 15.64 % for HF2 and 19.04% for M2 when compared with conventional concrete. The loss of strength is 20.55% for CM, 18.28% for HF2 and 18.610% for M2.
Abstract - In a HybridFibreReinforcedConcrete (HFRC), two or more different types of fibres are rationally combined to produce a cementitious composite that derives benefits from each of the individual fibres and exhibits a synergistic response. The main aim of the present experimentalinvestigation was to combine different fibres namely crimped stainless steel fibre and Glassfibre to produce HFRC and thus to evaluate its performance under compression, tension and flexure types of loading. The dimension of test specimens are of cube 150mmx150mmx150mm, cylinder of diameter 150mm, height 300mm, beam of 1000mmx150mmx100mm and 500mmx100mmx100mm Based on I.S. Code method of mix design, proportion of different ingredients was obtained to get M25 grade concrete. Samples were prepared by varying the volume fraction of fibres from 0 to 1.25% for each fibres individually and then the optimum percentage of fibres were combined to obtain HFRC.
When two different fibres are added to concrete to make the composite structure and it gives maximum strength to concrete that type of concrete is hybridfibrereinforcedconcrete (HFRC). In this experimental work using of two different fibres they are crimped steel fibre and polypropylene fibre with different mix proportion of hybrid fibres to form the hybridfibrereinforcedconcrete. Steel and polypropylene fibres have different properties and these properties will increases the tensile, flexural, impact strength of concrete. Initial cracks, shrinkage can be resist by using of polypropylene fiber and steel fiber is to increases the strength parameters. In present experimental work for M25 grade of concrete can be designed according to IS 10262:2009 with three different proportions of hybrid fibres are added with concrete ingredients. The proportion of steel and polypropylene fibres are added by 50% each with different hybridization ration i.e. 0%,0.5%, 1.0 %, 1.5% .For strength parameters compressive, tensile, flexural, impact strength specimens are casted and cured for 28 days and tested for hardened concrete. For durability study Sorptivity test is carried out to know the absorption of water by capillary. To evaluate the strength parameters different tests are conducted and results are tabulated. From the present work results showed that as the percentage of fibres increases the strength of concrete increases. Hybrid ratio 1.5 % gives maximum results in all the strength parameters compare to other different hybrid ratios.
The effect of steel fibres was studied by adding 0.5%, 1%, 1.5% and 2% by volume of 0.45 mm diameter steel fibres with aspect ratio 66 to the designed mix. The variations in fresh and hardened properties due to the addition of steel fibre on the mix are tabulated in Table 4. The workability decreased and the hardened properties such as cube compressive strength, cylinder compressive strength and modulus of elasticity increased with addition of fibres. Since the primary objective of fibre addition was improvement in tensile and flexural behaviour, optimum performance was observed for concrete with 1.5% of steel fibre addition. Hence for further study the percentage of steel fibre addition was fixed as 1.5%.
, 2016) experimental studies on high strength fibrereinforcedconcrete subject to plastic shrinking cracks Polyester & polypropylene fibres are better than glass fibre, because differences in stiffness, low elastic modulus and these are much longer than glass fibres. The steel and polyester hybrid combination is performed better than other combinations. are reduces the crack width, (Somasekharaih, Mahesh Sajjan, Nelson Mandela, 2015) study flexural behaviour of high strength steel fibrereinforcedconcrete beam were tested under two point load condition The test result indicates that the optimum fibre volume fraction was 1%. fraction resulted in higher load carrying capacity and enhanced ductility. (Venkatesan et al., 2015) Design method for two- layer beams consisting of normal and fibered high strength concrete". They analyzed two-layer concrete beam consisting the compressed zone of such beam section is made of high strength concrete (HSC) and the tensile one of normal strength concrete (NSC). research has been carried out on the ductility parameters, Poisson coefficient, energy dissipation (Iskhakov et al., 2014) Two-layer high-performance RC beams were used in the traffic (longitudinal) direction of long-span bridges for studies concrete grade variation in tension and compression zones of RCC beams. (Iskhakov and Ribakov, 2013) studied based on results of theoretical investigations and tests that showed high efficiency of such beams, carrying rather big bending moments As concrete in the tension zone of the section contributes little to the beam's load bearing capacity, this zone is made of NSC (Holschemacher, et al., 2012, Iskhakov et al., 2007, Eramma et al., 2011) two-layer bending
Abstract: This paper discusses the experimental results on the mechanical properties of hybridfibrereinforced composite concrete (HyFRCC) containing different proportions of steel fibre (SF) and polypropylene fibre (PPF). The mechanical properties include compressive strength, tensile strength, and flexural strength. SF is known to enhance the flexural and tensile strengths, and at the same time is able to resist the formation of macro cracking. Meanwhile, PPF contributes to the tensile strain capacity and compressive strength, and also delay the formation of micro cracks. Hooked-end deformed type SF fibre with 60 mm length and fibrillated virgin type PPF fibre with 19 mm length are used in this study.
ABSTRACT: Plain cement concrete is good at providing reasonable compressive strength but it tends to be brittle in nature and is weak in tensile strength, and minimum resistance to cracking, poor toughness. To overcome the deficiencies of concrete, fibers are added to enhance the performance of concrete. In the present study hybrid fibers consists of two different types of fiber combinations i.e. glass and polypropylene fibers are used with conventional concrete. The fiber proportions of of 0%, 0.25%, 0.5%, 0.75%, 1% and 1.25% by weight of cement is used. Strength parameters are compressive strength and split tensile strength will be tested and results were analyzed.
to be close to the corresponding steel bar reinforcedconcrete beams. A new reinforcement system consisted of FRP bars and steel bars was also proposed in Qu et al. It was reported that reinforcing concrete beams with both FRP bars and steel bars was an effective way for improving the serviceability and ductility of FRP bar reinforcedconcrete beams. Recently, in a few research investigations, it was observed that the deflection and crack width of FRP bar reinforcedconcrete beams were restrained and the ductility was improved by the addition of randomly distributed fibers[9,10]. There are many researches on the pure FRP reinforcedconcrete beam, Theoretical calculation is mostly based on the design specifications and guidelines of ordinary reinforcedconcrete beams or pure FRP reinforcedconcrete beamsand the research on flexuralperformance, crack width and deflection of hybridreinforcedconcrete beams is not sufficient.
Steel fiber reinforcedconcrete (SFRC) offers good tensile strength, ultimate strength, flexural strength, shock resistance, fatigue resistance, ductility and crack arrest. Some researches show that SFRC shows a slight tendency to reduce the young’s modulus as the fiber content decrease. Some of the experimental results show that the beams reinforced with steel fibers shows a similar or even better post cracking behavior than beams with minimum amount of transverse reinforcement.. Steel fiber also reduce the width of shear cracks, thus improve durability. The surface corrosion of steel fiber reinforcedconcrete mostly depends on the cover and the water-cement ratio. In some other research the combined effect of silica flume and steel fiber improved the impact resistance and mechanical properties of concrete.
concrete, having partial replacement of cement with waste marble powder. The result of investigation indicates that the replacement of 12% of cement with waste marble powder attains maximum compressive and tensile strength. The optimum percentage for replacement of marble powder with cement is almost 12% cement and it also minimizes the cost for construction with usage of marble powder which is freely available. Siddharth Sen and R Naga Vinothini (2015) studied the effects of addition of polypropylene fibers and granite powder on properties of concrete. The mechanical properties increased with age and thus the use of granite powder reduces the wastage disposal from granite industry. N. Venkata Ramana et.al (2016) conducted experimentalinvestigation on performance of Fibrereinforced stone waste aggregate concrete. From the results, it is observed that 50% replacement of natural aggregate by Black marble stone waste aggregate is desirable. Regression models were developed to estimate bearing strength of concrete and compared with IS 456-2000 code provision. Saranya Valivarthi and M Durga Rao (2016) presented experimental work on green concrete made with wastes. The fiber reinforced green concrete showed good strength enhancement by using marble sludge and stone dust for M-30 grade concrete. Rizwan Qadir and Fahad Perviaz (2016) presented the applications of coconut fiber and marble waste in construction and concluded that marble waste increases the compressive strength of concrete. G. Rajesh and E. Arunakanthi (2016) studied the fresh and hardened concrete properties of fiber reinforcedconcrete. An attempt was made to study the suitability of Bethamcharla waste stone aggregate in concrete works. Aquib sultan Mir and O P Mittal (2016) studied the effects of marble dust and steel fibers on steel fibers reinforcedconcrete. An immense increase in strengths in rigid pavement concretes was shown in results. Rajendra.D et.al (2017) conducted experimental work on partial replacement of coarse aggregate with waste cuddapah stone and PPC fly ash based cement. The results of fresh and hardened concrete properties were compared with conventional concrete and showed increase in strength of concrete. Subba Reddy singam and Sashidhar Chundapalle (2017) conducted experimentalinvestigation on utilization of marble waste in concrete. Here, NA was replaced with black stone marble waste and fibres were added. Better workability was achieved compared to natural coarse aggregate. Anisha S et.al (2017) conducted investigation on steel fibrereinforcedconcrete made with partial replacement of cement and addition of fibres.
being exposed to accelerated conditioning environments. Cory High et al. (2015) investigated the use of basalt fiber bars as flexural reinforcement for concrete members and the use of chopped basalt fibers as an additive to enhance the mechanical properties of concrete. Chaohua Jiang et al. (2014) studied the effects of the volume fraction and length of basalt fiber (BF) on the mechanical properties of FRC. Coupling with the scanning electron microscope (SEM) and mercury intrusion porosimeter (MIP), the microstructure of BF concrete was also studied. Fathima Irine et al. (2014) investigated the mechanical properties of Basalt fiber concrete and compare the compressive, flexural and splitting tensile strength of basalt fiber reinforcedconcrete with plain M30 grade concrete. Jon sung Sim et al. (2005) investigated the applicability of the basalt fiber as a strengthening material for structural concrete members through various experimental work for durability, mechanical properties and flexural strengthening. Kunal Singha (2012) presented a short review on basalt fiber. Mehmet Emin Arslan (2016) investigated the fracture behaviour of basalt fiber reinforcedconcrete (BFRC) and glass fibrereinforcedconcrete (GFRC). In the experimental study three-point bending tests were carried out on notched beams produced using BFRC and GFRC.Gore Ketan et al. (2013) evaluated the performance of high strength concrete (HSC) containing supplementary cementations materials. Concrete had a good future and is unlikely to get replaced by any other material on account of its ease to produce, infinite variability, uniformity, durability and economy with using of basalt fiber in high strength concrete. Nasir Shafiq et al. (2016) presentenced the flexural test results of 21 fiber reinforcedconcrete (FRC) beams containing Poly vinyl alchol (PVA) and basalt fibers (1-3% by volume) Fiber reinforcedconcrete was made of three different binders. Experimental results showed that the addition of PVA fibers significantly improved the post-cracking flexural response compared to that of the basalt fibers. Amuthakkannan et al. (2013) focused on the effect of fibre length and fibre content of basalt fiber on mechanical properties of the fabricated composites. TianyuXie and Togay Ozbakkaloglu (2016) conducted experimental study on the axial compressive behavior of concrete filled FRP tubes (CFFTs), prepared using different amounts of recycled concrete aggregate (RCA).
The flexural strength of GI fibrereinforced transparent concrete goes on increasing up to 1.5% addition of GI fibres in it. After 1.5 % addition, the flexural strength decreases. The percentage increase in the flexural strength is found to be 55.56% when 1.5% GI fibres are added with reference to the conventional concrete without optical fibres. Thus the higher flexural strength for GI fibrereinforced transparent concrete may be obtained by adding 1.5% GI fibres.
Hybridfibrereinforcedconcrete is the one in which more than one or two types of fibers are used as secondary reinforcement. Fibres have been used to reinforce materials that are weaker in tension than in compression. However for any reinforcement to be effective, it must be stiffer than the concrete matrix that is reinforcing. Generally the less stiff fibres only offer benefits in improving the tensile strength of plastic and semi-hardened concrete and are therefore mainly used to reduce plastic shrinkage and plastic settlement cracking until now, most of the production of HFRC has been for non-structural applications, with the fibres added primarily for control of cracking due to plastic or drying shrinkage. The aim of this project is to determine the behaviour of the hybridfibrereinforcedconcrete slabs under cyclic loading. The fibres used here are polyolefin and steel corrugated fibres. The percentage of fibres used here are 0.5%, 1%, 1.5% and 2%. So far the experimental works has been done under impact loading. The main aim of this project is to determine the flexural behaviour of hybridfibrereinforcedconcrete beam under cyclic loading .the beam size adopted here is 1000mmx 150mmx170mm.
For the preparation of the examined beams, the reinforcement was assembled first, and then the reinforcement was placed in the moulds. Once the reinforcement was ready, the concrete was poured in the moulds. The concrete mixture design used for the initial beams is presented in Table 2. All the initial beams were wet cured daily for 28 days, while after this period the beams were wet cured every two days and until the casting of the layers. For the preparation of the UHPFRC, silica sand with a maximum particle size of 500μm was used together with silica fume, Ground Granulated Blast Furnace Slag (GGBS) and cement class 52.5 R type I. Low water/cement ratio of 0.28 was also used together with polycarboxylate superplasticizer. A percentage of 3% per volume steel fibers was used for the preparation of the UHPFRC mixture. In this investigation straight steel fibers with a length of 13 mm, a diameter of 0.16 mm, and a tensile strength of 3000 MPa were used, while the modulus of elasticity was 200 GPa. The examined mixture design is presented in Table 3.
Fuat Ko Ksal et al (2007) experimentally investigated on the mechanical properties of concrete specimens produced by using silica fume and steel fibre. The main objective of this work was to obtain a more ductile high strength concrete produced by using both silica fume and steel fibre. Two types of steel fibre with aspect ratios (fibre length/fibre diameter) of 65 and 80 were used in the experiments and volume fractions of steel fibre were 0.5% and 1%. Additions of silica fume into the concrete were 0%, 5%, 10% and 15% by weight of cement content. Water/cement ratio was 0.38 and the reference slump was 120 ± 20 mm. Slump test for workability, air content and unit weight tests were performed on fresh concretes. Compressive strength, splitting tensile strength and flexural strength tests were made on hardened concrete specimens. Load–deflection curves and toughness of the specimens were also obtained by flexural test performed according to ASTM C1018 standards. Flexural tests on beam specimens were achieved using a closed loop deflection-controlled testing machine. The use of silica fume increased both the mechanical strength and the modulus of elasticity of concrete. On the other hand, the addition of steel fibre into concrete improves toughness of high strength concrete significantly. As the steel fibre volume fraction increases, the toughness increases, and high values of aspect ratios give higher toughness. The toughness of
Synthetic fibres have become more popular in recent years as secondary reinforcement in cementitious materials. This is due to the fact that they can provide effective and relatively inexpensive reinforcement for concrete compared to conventional fibres such as asbestos, steel and glass. Synthetic fibre types that have been utilized in cementitious matrices so far are namely; polyethylene (PE), polypropylene (PP), acrylics (PAN), polyviny1 alcohol (PVA), polyamides (PA), aramid, polyester (PES) and carbon. The properties of synthetic fibres may vary broadly, especially in term of modulus of elasticity. This characteristic plays an important role when fibres are used for producing composites (Zheng & Feldman 1995).
The concrete covering is made rough using a coarse sandpaper texture and then cleaned with an air blower to remove all dirt and debris at the time of bonding of fiber. After that, the epoxy resin is mixed in accordance with the manufacturer’s instructions. The mixing is sent out in a plastic container (100 parts by weight of Araldite LY 556 to 10 parts by weight of Hardener HY 951). After their uniform mixing, we can cut the fabrics according to the size then the epoxy pitch is applied to the concrete surface. Then the BFRP sheet is placed on the head of epoxy pitch coating and the pitch is squeezed over the rambling of the fabric with the roller. Air bubbles captured at the epoxy/concrete or epoxy/fabric interface are discarded. While solidification of the epoxy, a consistent uniform pressure is applied on the composite fabric surface in order to eject the excess epoxy pitch and to assure satisfying contact between the epoxy, the concrete, and the fabric. This procedure is carried out at room temperature. Concrete beams reinforced with glass fiber fabric are preserved for 24 hours at room temperature before the examination.