ISSN Vol.05,Issue.04, April-2017, Pages:

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1 ISSN Vol.05,Issue.04, April-2017, Pages: G. K. MANASA 1, CH. VENKATA RAMANA 2, P. SAI PRADEEP 3 1 PG Scholar, Dept of Structural Engineering, Rise Krishna Sai Prakasam Group of Institutions, Ongole, AP, India, gkvmanasa@gmail.com. 2 Assistant Professor, Dept of Structural Engineering, Rise Krishna Sai Prakasam Group of Institutions, Ongole, AP, India, kvr.kokkilagadda@gmail.com. 3 Assistant Professor, Dept of Structural Engineering, Rise Krishna Sai Prakasam Group of Institutions, Ongole, AP, India, pradprady@gmail.com. Abstract: Reactive Powder Concrete (RPC) is an ultra-high strength and high ductility composite material with advanced mechanical properties. It is developed in 1990 s by the French Company Bouygues. It is a special wherein the microstructure is optimized by precise gradation of all particles in the mix to yield maximum density. RPC extensively uses the pozzolanic properties of highly refined silica fume and optimization of the Portland cement chemistry to produce the highest strength hydrates. It represents a new class of Portland cement based material with compressive strengths of range 150Mpa. The flexural strength is also to be ranges from Mpa. The material exhibits high ductility with values of energy absorption approaching those that are reserved for only metals. The RPC concept is based on the principle that a material with a minimum of defects such as micro-cracks and voids will be able to achieve a greater load carrying capacity and greater durability. And finally, the purpose of this investigation is to attribute to the refinements in RPC with an introduction of graded aggregate (3-8mm) and also do the without of coarse aggregate is to be done by the Ordinary Reactive Powder Concrete (ORPC). So as to make this RPC more economical and feasible without much reduction in its mechanical properties. This modification makes the traditional RPC as an innovative MRPC (Modified Reactive Powder Concrete). The RPC is with and without of Coarse aggregate is tested in compressive and flexural strength using steel fibers. To find flow of is also to be measured in the addition of steel fibers without coarse aggregate only. Keywords: Ordinary Reactive Powder Concrete (ORPC), Ultra High-Performance Concrete (UHPC), High-Range Water Reducer (HRWR). I. INTRODUCTION A. Reactive Powder Concrete Recently, very high strength cement based composite with high ductility called Reactive Powder Concrete (RPC) has been developed in Bouygues, France (Richard and Cheyrezy, 1994). Reactive Powder Concrete provides many enhancements in properties compared to conventional and high strength of all particles in the mix to yield maximum density. The term Reactive Powder Concrete (RPC) has been used to describe a fibre-reinforced, super plasticized, silica fume-cement mixture with very low watercement ratio (w/c) characterized by the presence of very fine Quartz sand ( mm) instead of ordinary aggregate. In fact, it is not a because there is no coarse aggregate in the cement mixture. The absence of coarse aggregate was considered by the inventors to be a key aspect for the microstructure and the performance of the RPC in order to reduce the heterogeneity between the cement matrix and the aggregate. RPC represents a new class of Portland cement based material with compressive strength s in excess of 200mpa. By introducing fine steel fibres, RPC can achieve remarkable flexural strength up to 50mpa. The material exhibits high ductility with typical values for energy absorption approaching those reserved for metals. B. Development Of RPC RPC was developed by the French engineers in the 1990s [6]. Richard and Cheyrezy presented the initial composition in which they eliminated coarse aggregates to enhance the homogeneity. The bond between the coarse aggregate and the cement paste are the weakest links in the matrix, so to improve strength the coarse aggregates were removed from the composition. However, other studies have indicated that addition of coarse aggregate does not necessarily reduce the compressive strength. The use of the coarse aggregates led not only to the decrease in cementitious paste volume fraction, but also necessitated changes in the mixing process and in the consequent mechanical properties. RPC containing coarse aggregate was more easily fluidised and homogenized. The mixing time was found to be shorter than for RPC without coarse aggregates. Formulations with and without coarse aggregate exhibited a similar behaviour under compressive loading, although with somewhat different modulus of elasticity and strain at peak stress, which was dependent on the stiffness of the aggregates. The lower paste volume fraction and the physical resistance of the stiffer basalt aggregate resulted in a lower autogenous shrinkage of the RPC containing coarse aggregates. The initial purpose of adding coarse aggregates was to reduce the cement usage so that the costs of construction could be lowered. Work has 2017 IJIT. All rights reserved.

2 been undertaken where artificial aggregate was used to replace natural ones with clinker-aggregates resulted in an increase of strength (by about 20MPa) compared to natural aggregates. C. Advantages Of RPC Better alternative to HPC. High Tension Ductile failure mechanism eliminates the need for reinforcing steel. Improved seismic performance by reducing inertia loads with lighter members. Low and non-inter connected porosity diminishes mass transfer. The main advantage that RPC has over standard is its high compressive strength. RPC construction requires low maintenance costs in its service life. D. Applications Of RPC RPC has found application in the storage of nuclear waste, bridges, roofs, piers, seismic-resistant structures and structures designed to resist Impact/blast loading. Owing to its high compression resistance, precast structural elements can be fabricated in slender form to enhance aesthetics. Durability issues of traditional have been acknowledged for many years and significant funds have been necessary to repair aging infrastructure. Reactive Powder Concrete possesses good durability properties. RPC usually incorporates larger quantities of steel or synthetic fibres and has enhanced ductility and high temperature performance. II. LITERATURE REVEIW M K Maroliya (2012), An Investigation on Reactive Powder Concrete containing Steel Fibers and Fly- Ash The primary focus of this development has been on the achievement of greater compressive strengths and it is now no longer possible to refer to all s as merely. The production of very high strength normal weight Reactive powder (RPC) requires detailed investigation of number of factors that have and what can be done to optimized their contribution to the attainment of very high compressive strength. Studied were the effects of water to cement ratio, curing conditions, compositions and the effect of mineral and chemical admixtures to achieve higher compressive strength. S. Collepardi, L. Coppola, R. Troli, M. Collepardi, Mechanical Properties of Modified Reactive Powder Concrete, Original Reactive Powder Concrete (RPC) - in form of a superplasticized cement mixture with silica fume, steel fibers and ground fine quartz ( mm) - was studied in comparison with a modified RPC where a graded natural aggregate (max size 8 mm) was used to replace the fine sand and/or part of the cementitious binder. Original and modified RPC were manufactured at a plastic-fluid consistency, cast by vibration and cured at three different conditions: a) room temperature; b) steam-curing at 90 C; c) G. K. MANASA, CH. VENKATA RAMANA, P. SAI PRADEEP high pressure steam-curing at 160 C. The addition of the graded aggregate does not reduce the compressive strength provided that the quality of the cement matrix, in terms of its water-cement ratio, is not changed. This result is in contrast with the model proposed to relate the high compressive strength level of RPC (200 MPa) to the absence of coarse aggregate. Both the original and modified RPC (with the coarse aggregate addition) perform better in terms of higher strength and lower driying shrinkage or creep strain - when they are steam cured rather than cured at room temperature. This improvement was related to a more dense microstructure of the cement matrix, particularly in the RPC specimens steam cured at 160 C. Olivier Bonneau, Mohamed Lachemi, ÉricDallaire, JérômeDugat, and Pierre-Claude Aïtcin (1997), Mechanical Properties and Durability of Two Industrial Reactive Powder Concretes, Two reactive powder s (RPC) were produced on an industrial scale at the Université de Sherbrooke and in a nearby precast plant. A 2.6 m3 mix was prepared in a ready mix truck while a 1.35 m3 mix was prepared in the central mixer of the precast plant. The ready mix RPC was sampled before and after the addition of steel fibers while the one produced at the precast plant was sampled only at the end of the mixing process. These RPCs were tested for compressive strength, modulus of elasticity, freezing and thawing cycling resistance, scaling resistance to deicing salts, and resistance to chloride ion penetration. Large samples were also cast allowing core samples to be taken. The results show that a 200 MPa compressive strength could be achieved in both cases: after curing in hot water at 90 deg C or in the low pressure steam chambers at the precast plant. Confinement of the RPC in a steel tube greatly increases its compressive strength and its ductility. The two mixes were found to be freeze-thaw resistant and presented a very low mass loss under the scaling test. Chloride ion permeability was below 10 Coulombs even for the specimens containing steel fibers; this extremely low value translates to the quasi-impermeability of the two RPCs. Kay Wille, Antoine E. Naaman, and Gustavo J. Parra-Montesinos (2011), Ultra-High Performance Concrete with Compressive Strength Exceeding 150 MPa (22 ksi): A Simpler Way, Although intensive research related to ultra high-performance (UHPC) and its composition has been carried out over the past two decades, attaining compressive strengths of over 150 MPa (22 ksi) without special treatment, such as heat curing, pressure, and/or extensive vibration, has been nearly out of reach. This paper describes the development of a UHPC with a compressive strength exceeding 200 MPa (30 ksi), which was obtained using materials commercially available in the U.S. market and without the use of any heat treatment, pressure, or special mixer. The influence of different variables such as type of cement (C), silica fume (SF), sand, and high-range water reducer (HRWR) on compressive strength is evaluated. The test results show that the spread value, measured through a slump cone test on a flow table, is a good and quick indicator

3 to optimize the mixture packing density and thus its compressive strength. Mr. M K Maroliya (2012), A State Of Art- On Development Of Reactive Powder Concrete, Low flexural tensile strength has number of undesirable consequences for its performance as an effective building material. These include necessity of auxiliary steel reinforcement and thick sectioned members that are both aesthetically unappealing and consume significant quantities of aggregates. An emerging technology with the potential to overcome these limitations is reactive powder (RPC) RPC is a cold cast cementitious material in which the mechanical properties of the matrix are improved by suppression of the weak interfacial transition zone normally developed around the aggregate through improved particle packing and by refinement of the hydrated paste microstructure by extensive use pozzolanic silica and elevated temperature curing. Tensile capacity is provided by steel micro fibres rather than conventional reinforcement the low and non connected porosity of RPC also render extremely durable. RPC offers the possibility building with with slender member with improved seismic response. F.A = 2355-( ) = 687 kg/m3 TABLE I: Mix Proportions for the RPC with Coarse Aggregate B. Mix Design for RPC without Coarse Aggregate In this mix design the w/c ratio is assumed to 0.3 and the cement conent is increased by the first mix. Weight of water = 220 kg/m3 Weight of cement = 733 kg/m3 Weight of quartz sand = 257 kg/m3 Weight of river sand = 1136 kg/m3 TABLE II: III. EXEPERIMENTAL PROGRAM A. Mix Design for RPC with Coarse Aggregate To developed the mix proportions for the replacement of coarse aggregate is to be used Characteristic strength of is 150 Mpa, Specific gravity of F.A and C.A is 2.63 and 2.8 respectively. Step 1: The mean target strength fm =f min+ ks = *6 Step 2: the assumed water content ratio is 0.28 Step 3: For slump of 50 mm, 10 mm aggregate maximum size of aggregate, for non air entrained The mixing water content is 205 kg/m3 of Te required cement content = 205/0.28 =732 Step 4: from 10mm coarse aggregate fineness modulus is 2.40 and dry rodded bulk density volume of coarse aggregate is 0.50 per unit volume of Step 5: the weight of coarse aggregate =0.50*1800=900kg/m3 Step 6: The estimated density of fresh for 10mm maximum size of aggregate for non air entrained = 2285 kg/m3 Step 7: The weight of all the known ingredient of Weight of water = 205 kg/m3 Weight of cement = 733 kg/m3 Weight of C.A = 900kg/m3 Weight of F.A = ( ) = 447 kg/m3 The mix proportion is C: F.A:C.A: Water =733:447:900:205 1:0.60:1.22:0.28 C. Comparison of RPC without And With Coarse Aggregate From the above results we can take the four mix proportions i.e., 0.27, 0.25, 0.24, 0.22 of the results are compare with the RPC and RPCCA. TABLE III: RPC = Reactive Powder Concrete without coarse aggregate RPCCA = Reactive Powder Concrete with coarse aggregate If the cement content is greater than 500kg/m3 So we can reduce the cement content is 600kg/m3 Fig.1. Water = 0.28*600 =168kg/m3

4 Form the above Fig.1 the compressive strength is reducing the addition of coarse aggregate. D. Compressive Strength Results Of Addition Of Steel Fibres is 20 % of the RPC and RPCCA TABLE IV: G. K. MANASA, CH. VENKATA RAMANA, P. SAI PRADEEP Flexural Strength Results of RPC and RPCCA with Steel Fibres: TABLE VII: From the above results the flexural strengths graph is to be as below RPCSF = Reactive Powder Concrete with steel fibres. RPCCASF =Reactive Powder with C.A and steel fibres. E. Comparison Of RPC And RPCCA With The Addition Of Steel Fibres Fig.5. Fig.2. F. Flexural Strength Results of RPC and RPCCA and Steel FIBERS Flexural Strength Results of RPC and RPCCA: TABLE V: From the above results the flexural strengths graph is to be as below IV. CONCLUSION From the above results we can conclude that RPC and RPCCA have very slight variations in compressive strength and also flexural strength values. At water cement ratio as low as 0.22, polycarboxylic ether gives good workable, but normal super plasticizers like SNF requires higher water-cement ratio. The results show that silica fume gives better compressive strength and good flow at lower watercement ratio. Workability is not achieved when coarse aggregate is used in MRPC. From the table 1 on average compressive strength is increased by 3 % for RPC than RPCCA. From the table 2 on average compressive strength is increased by 20 % for RPCSF than RPCCASF. From the table 3 on average of flexural strength is increased by 6 % for RPC than RPCCA. From the table 4 on average of flexural strength is increased by 8 % for RPCSF than RPCCASF. If the coarse aggregate is used the workability is not coming. The cost of RPC is less than the MRPC. Fig.3. V. REFERENCES [1]Richard, P., and Cheyrezy, M H RPC with high ductility and compressive strengths of 200 Mpa order, [2]Cheyrezy.M, Maret.V, Frouin.L (1995) microstructure analysis for RPC cements research, vol.25 no.7pp [3]Benjamin A. Graybeal. (2006) Practical Means For Determination of the Tensile Behaviorop of Ultra-High Performance Concrete. Journal of ASTM International, Vol. 3, No. 8, pp. 1-9.

5 [4]The Indian Concrete Journal, November Editorial Concrete Without Coarse Aggregate [5]CONCRETE Microstructure, Properties, and Materials by P. Kumar Mehta and Paulo J. M. Monteiro. [6]Indian Standard METHOD OF MAKING, CURING AND DETERMINING COMPRESSIVE STRENGTH OF ACCELERATED-CURED CONCRET TEST SPECIMENS, IS: [7]Indian Standard CONCRETE MIX PROPORTIONING- GUIDELUINES, IS 10262:2009. [8]Neville, A.M. Properties of Concrete, Fourth Edition, 1995, Editor: Longman Group Limited, Essex, England, p. 844 [9]Silica fumes Manual. ELKEM India Pvt. Ltd. Mumbai. [10]Standard test method for Flexural performance of fibre reinforced (Using Beam with third point loading). [11]Marcel Cheyrezy, Vincent Maret, and Laurent Frouin. Micro-structural analysis of RPC (Reactive powder ). Cement and Concrete Research, 1995, Vol. 25, No. 7 [12] Concrete Technology by M.S.Shetty.