Size Effect on Shear Behavior of Reactive Powder Concrete Containing Steel Fibres and Silica Fume

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1 Vol. 2, Issue. 5, Sep.-Oct. 212 pp ISSN: Size Effect on Shear Behavior of Reactive Powder Concrete Containing Steel Fibres and Silica Fue Mr. M. K. Maroliya Assistant professor, Applied Mechanics Dept, Faculty of Technology & Engineering, M. S. University of Baroda, Vadodara, ABSTRACT: To focus on a structural perforance in response to intense shear loading, a series of direct shear speciens rando oriented fibres in shear failure plane were tested using optiized coposition of RPC A siple shear strength test setup is proposed which is found to provide reliable and consistent results. The experiental results show that RPC exhibits ductile failure ode, higher ultiate strength and slip capacity in addition to uch iproved structural integrity. This enhanceent of perforance, however, reduces with decrease in size of Specien. Key Words: RPC, Strain hardening, Ductility, Slip capacity. I. INTRODUCTION Shear failure is generally brittle in concrete structures. Exaples of concrete structural failure related to shear loading are bridge deck punching shear, corbel failure, anchor bolt pull out and segental bridge shear key failure a otivation of the work presented here is to odify the brittle failure ode by taking advantage of unique aterial behavior of RPC. It is a fiber reinforced ceent based aterial with designed icrostructure such that coposite undergoes pseudo strain hardening instead of softening when first crack strain is exceeded. As a result, RPC is characterized by ultiate tensile strain and fracture energies which can be higher than conventional ceentitious aterials. The present study is priarily concerned with the translation of pseudo strain hardening properties of RPC fro aterial level to structural level. A nuber of researchers have reported about the use of fibers as a replaceent for shear reinforceent to enhance shear capacity of concrete beas in order to ensure a ductile final failure in flexure in RCC beas [3]. They ephasized testing of conventional reinforced beas to study the effect of shear span to effective depth ratio, fiber type, volue fraction and aspect ratio and the longitudinal steel content on shear capacity. But experience shows that two planes failing siultaneously in double shear for bea speciens never happens in reality and hence shear strength calculated in this anner could be erroneous. On the other hand, an attept to get one failure plane in shear in bea and colun specien directly under copression testing achine invites undue eccentricity since one portion of the specien needs to be held fixed with respect to the other part. Hence, there exists no standard, reliable and siple ethod to get direct shear strength. Sliding of one layer over the other layer with slip at coon surface of contact gives realistic picture of direct shear. An attept is ade in the present paper to get direct shear strength of RPC aterial using a siplified and reliable test setup, both in conventional UTM under load control with large size specien giving 2D effect of fiber orientation and MTS achine under displaceent control with saller size specien giving 1D effect of randoly oriented fibres in shear failure plane. Reactive Powder Concrete has higher durability, higher fatigue, and ipact and abrasion resistances. With these unique properties, there is a potential for substantial reductions in cross-section diensions reducing the weight of ebers which directly ipact on substructure and erection cost. Further, for RPC beas without conventional shear reinforceent lower anpower and supervision cost are also a consideration when considering total long ter costs. In ter of structure perforance, the inclusion of discrete fibers into the concrete atrix can arrest cracks and thereby control crack propagation. II. MATERIAL COMPOSITION TABLE: 1. OPTIMIZED COMPOSITION OF RPC Mixture RPC 1 RPC 2 RPCF 3 RPCF 4 Ceent Silica Fue Quartz Sand Sand 15 6µ Super Plasticizer Steel Fibers Water/Ceent Copressive Strength (7-days) N/ Copressive Strength (28-days) N/ Flexural Strength (N/ 2 ) Page

2 Vol. 2, Issue. 5, Sep.-Oct. 212 pp ISSN: RPC 1 = RPC without Steel Fibers at noral Curing RPC 2 = RPC with Steel Fibers at hot water Curing RPCF 1 = RPC with Steel Fibers at noral Curing RPCF 2 = RPC with Steel Fibers at hot water Curing III. LITERATURE REVIEW Bairagi and Modhera [11, 12] checked the feasibility and reliability of the test ethod proposed by the with the test ethod suggested by JSCE ethod. Results obtained by their proposed ethod were 1% higher than that of JSCE ethod. They concluded that by coparing the procedure of test ethods and fabrication of test asseblies as well as the test specien, their proposed ethod is sipler to handle copared to JSCE ethod. During the perforance of the test using the arrangeent as suggested by Bairagi and Modhera, it was seen that the roller penetrates down in the specien, not giving the correct picture of the failure. Also the results reported by the were on higher side copared to that of JSCE ethod in case of fiber reinforced concrete saples. IV. SPECIMEN AND TEST SET-UP In the present study the influence of steel fiber variation on Shear strength of RPC have been studied. Different size of L-shape oulds are used for the preparation of saples. Three different percentage of steel fiber (i.e.., 1., 2. & 3.%) added in the RPC ixture and copare the shear strength of RPC. The variations in the shear strength gained fro the different steel fiber variation are tabulated in the table FIG.1.: TWO TYPES OF L-SHAPED SPECIMENS FIG.2.: SHEAR TEST SET UP ON MTS V. RESULTS AND DISCUSSION Experiental results presented shows that the ultiate single shear strength for RPC with inclusion of fibers increases considerably with reference to plain RPC. With addition of fiber the speciens do not fail suddenly and the failure load is ore than the first crack load. The quantity of fibers used in plain RPC do not significantly affect the first cracking load but a significantly influence on the rate of crack propagation and on the failure load. Typical shear strength variation with respect to fiber volue fraction and shear plane variations has been plotted in FIG 3. & FIG 4.. It can be noted that the axiu increase in shear strength is found for 2% fiber volue fraction than %, 1%, 3% fiber volue. For L shape shear specien we had observed that shear strength increase for shear plane width 23 than 28, 33, 37 in 2% fiber volue in FIG 4. and shear plane 28, 33, 37 of 2% fiber volue shear strength increase in copare shear plane 28, 33, 37 of %, 1%, 3% fiber volue. By referring fig.5 to fig.8 it is observed that the area below the curve is increases we increases fibre content as well as post peak perforance is also enhanced to a large extant Page

3 Load (N) Avg Shear Strength (MPa) Avg Shear Strength (MPa) Vol. 2, Issue. 5, Sep.-Oct. 212 pp ISSN: X 23 7 x 28 7 x 33 7 x % 1% 2% 3% Fiber (%) FIG.3.: SHEAR STRENGTH OF RPC WITH STEEL FIBRE VARIATION % 1.% 1.5% 2.% 2.5% Fibre (%) 15 X 6 15 X7 15 X 8 FIG: 4. SHEAR STRENGTH OF RPC WITH STEEL FIBRE VARIATIONS % Fiber Displaceent () FIG.5.: EFFECT OF.% STEEL FIBER IN DIFFERENT SHEAR DEPTH 3936 Page

4 Load (N) Load (N) Load (N) Vol. 2, Issue. 5, Sep.-Oct. 212 pp ISSN: % Fiber Displaceent 1 () FIG.6.: EFFECT OF 1.% STEEL FIBER IN DIFFERENT SHEAR DEPTH 6 4 2% Fiber Displaceent 1 () FIG.7.: EFFECT OF 2.% STEEL FIBER IN DIFFERENT SHEAR DEPTH 5 4 3% Fiber Displaceent.6 () FIG.8.: EFFECT OF 3.% STEEL FIBER IN DIFFERENT SHEAR DEPTH VI. CONCLUSIONS The proposed direct shear test is not only siple but also ost suitable for the RPC coposite. It indicates ore realistic and efficient sliding echanis in shear. Steel tends to enhance the shear strength uch better than orientation effect could be closely seen as the shear strength of the saller specien and bigger speciens for all the atrices, deforation characteristics in shear could be evaluated better by testing the speciens in displaceent control instead of load control. Maxiu shear strength obtained in SF-RPC is quite high then ordinary concrete However, results of SF-RPC are uch scattered as ost of the speciens failed by fracture control after a foration of first crack, steel fibres being very strong and stiff in shear ake it possible to resist large aount of load if fibres are available in the resisting plane. Due to presence of fibres ductile failure is observed.in fact crack get arrested by fibres does not get fractured but pulling out of fibres fro atrix is observed. Experiental results shows that higher the thickness of shearing plane higher the value of shearing strength. However, optiu value results can be obtained at 6 to 75 depth Page

5 Vol. 2, Issue. 5, Sep.-Oct. 212 pp ISSN: RPC speciens achieved uch higher load carrying capacity and slip capacity in shear and were gradually daaged by ductile yielding. This phenoenon is due to ductile nature of RPC aterial and results of which confirs switching of failure ode fro brittle concrete fracture to ductile yielding of RPC aterial with iproved structural integrity. Such advantageous translation of structural shear response can effectively iprove seisic resistance of building fraes REFERENCES 1) A. S. Dili and Manu Santhana (24) Investigation on Reactive Powder Concrete: A Developing Ultra High- Strength Technology Indian Concrete Journal. 2) Abdeldjelil and Thoas T.C.Hsu (1995) Constitutive Laws of Softened in Biaxial Tension-Copression ACI Structural Journal, Vol 92 No.[5] 3) Abouzar Sadrekarii. (24) Developent Of A Light Weight Reactive Powder Concrete. Journal Of Advanced Concrete Technology Vol. 2, no. 3, ) Aicha Kaen, Eanuel Denarie And Eugen Bruhwiler. (27) Theral Effects On Physico-Mechanical Properties Of Ultra-High-Perforance Fiber-Reinforced Concrete, ACI Material Journal. 5) Ali R. Khaloo and Nakseok ki. (1997) Influence Of Concrete And Fiber Characteristics On Behaviour Of Steel Fiber Reinforced Concrete Under Direct Shear ACI Structural Journal, Vol. 94 No.[6]. 6) Aar Hassan And Makoto Kawakai (25) Steel Free Coposite Slabs Made Of Reactive Powder Materials And Fiber Reinforced Concrete, ACI Structural Journal, Vol. 12 No. [5]. 7) Arnaud Poitou, Francisco Chinesta, And Ge Rard Bernier. Orienting Fibers by Extrusion In Reinforced Reactive Powder Concrete. 8) ASTM International Standard Test Method for Copressive Strength of Hydraulic Ceent Mortars, (using [5-] cube speciens), C-19/c 19 5, C ) ASTM International Standard Test Method for Flow Of Hydraulic Ceent Mortar, C , 1) B.I.G.BARR and K.L.W.LIU (1983) A copact test specien Journal Of Materials Science Letters ) Bairagi N. K. and Modhera C.D. (21) Shear Strength of Fibre Reinforced Concrete ICI Journal Vol 1 No.[4]. 12) Bairagi, n. K. & Modhera, C. D. (24) An Experiental Study Of Shear Strength Test Method For SFRC, Proceedings Of International Conference On Advances In Concrete And Construction, Vol. No Page

MECHANICAL AND RHEOLOGICAL PROPERTIES OF FIBER REINFORCED SELF COMPACTING CONCRETE WITH ALCCOFINE Arun Raja.L 1, Dr. M.

MECHANICAL AND RHEOLOGICAL PROPERTIES OF FIBER REINFORCED SELF COMPACTING CONCRETE WITH ALCCOFINE Arun Raja.L 1, Dr. M.Shahul Haeed 2 1 Assistant Professor, 2 Professor Departent of Civil Engineering,