Your SlideShare is downloading. ×
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Factors affecting the strength of reactive powder concrete rpc
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Factors affecting the strength of reactive powder concrete rpc

2,158

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
2,158
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
124
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. INTERNATIONAL JOURNAL and Technology (IJCIET), ISSN 0976 – 6308 International Journal of Civil Engineering OF CIVIL ENGINEERING AND (Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME TECHNOLOGY (IJCIET)ISSN 0976 – 6308 (Print)ISSN 0976 – 6316(Online)Volume 3, Issue 2, July- December (2012), pp. 455-464 IJCIET© IAEME: www.iaeme.com/ijciet.aspJournal Impact Factor (2012): 3.1861 (Calculated by GISI) © IAEMEwww.jifactor.com FACTORS AFFECTING THE STRENGTH OF REACTIVE POWDER CONCRETE (RPC) Khadiranaikar R.B. and Muranal S. M. Mr. Santosh M. Muranal M.Tech (Str.Engg) Assistant Professor, Dept. of Civil Engineering Basaveshwar Engineering College Vidyagiri, BAGALKOT-587102 Karnataka, India Email-Id: murnal.santosh@gmail.com Dr. R. B. Khadiranaikar M.E, PhD(IIT, Delhi) Professor, Dept. of Civil Engineering Basaveshwar Engineering College Vidyagiri, BAGALKOT-587102 Karnataka, India Email-Id: dr.rbknaikar@gmail.com ABSTRACT Reactive Powder Concrete (RPC) is catching more attention now days because of its high mechanical and durability characteristics. RPC mainly comprises of cement, silica fume, silica sand, quartz powder and steel fibers. RPC has been able to produce with compressive strength ranging from 200 MPa to 800 MPa with flexural strength up to 50 MPa. Although suitable guidelines are not available to produce RPC in India, the present study focuses on developing RPC of compressive strength up to 150 MPa. Along with the development of RPC, various factors affecting the strength of RPC are studied. The 100×100×100 mm size RPC cube specimens were cast by varying the constituent materials and cured at both normal and high temperature before testing for their strength. The compressive strength of 146 MPa was achieved with the mix considered. It is observed from the study that w/b ratio, silica fume content, quartz powder, high temperature curing significantly affects the compressive strength of RPC. It was observed that addition of quartz powder and high temperature curing increases the compressive strength up to 10 percent when compared with specimens tested after normal room temperature curing. The material can be effectively utilized in the production of precast elements/PSC structures. 455
  • 2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEMEKeywords: Reactive powder concrete, silica fume, quartz powder, accelerated curing, compressivestrength.1. INTRODUCTIONReactive Powder Concrete (RPC) is an ultra high strength and high ductile composite material withadvanced mechanical properties. Reactive powder concrete is a concrete without coarse aggregate, butcontains cement, silica fume, sand, quartz powder and steel fiber with very low water binder ratio.The absence of coarse aggregate was considered by inventors to be key aspect for the microstructureand performance of RPC in order to reduce the heterogeneity between cement matrix and aggregate(Richard et al. 1995).The original concept of RPC was first developed, in early 1990, by researchers at Bouygueslaboratory in France. The addition of supplementary material, elimination of coarse aggregates, verylow water/binder ratio, additional fine steel fibers, heat curing and application of pressure before andduring setting were the basic concepts on which it was developed (Richard et al. 1995). Compressivestrength of RPC ranges from 200 to 800 MPa, flexural strength between 30-50 MPa and Young’smodulus up to 50-60 GPa. There is a growing use of RPC owing to the outstanding mechanicalproperties and durability. RPC structural elements can resist chemical attack, impact loading fromvehicles and vessels, and sudden kinetic loading due to earthquakes. Ultra high performance is themost important characteristic of RPC (Gilliland et al. 2007). RPC is composed of more compact andarranged hydrates. The microstructure is optimized by precise gradation of all particles in the mix toyield maximum density. It uses extensively the pozzolonic properties of highly refined silica fume andoptimization of the Portland cement chemistry to produce highest strength hydrates (Cheyrezy et al.1995; Reda et al. 1999).RPC will be suitable for pre-stressed application and for structures acquiring light and thincomponents such as roofs of stadiums, long span bridges, space structures, high pressure pipes, blastresistance structures and the isolation and containment of nuclear wastes (Gowripalan et al. 2003;Bonneau et al. 1996; Hassan et al. 2005). In India the work on RPC has started from last few years.SERC, Chennai, worked towards the development of the UHSPC with and without steel fibers and theeffect of various heat curing regimes adopted on the strength properties of the mixtures (Harish et al.2008). Dili A.S. and Manu Santhanam (2004) have studied mix design, mechanical properties anddurability aspects of RPC. The utility of RPC in actual construction is minimal or nil in India, it isbecause of non-availability of sufficient experimental data regarding production and performance ofRPC. So the basic objective of the current investigation is to experience the production of RPC. Thekey issues of the study are: to develop RPC of compressive strength up to 150 MPa, to determine theeffect of silica fume content on compressive strength, to determine the effect of high temperaturecuring on the compressive strength and to determine the effect of addition of quartz powder on thecompressive strength of RPC. As the standard code is not available to design RPC, here an attempt is made to design RPC mix withlocally available materials referring literature. The RPC cube specimens were cast and cured for bothnormal and high temperature curing. The cured specimens were tested to evaluate the compressivestrength.2. EXPERIMENTAL DETAILS 2.1 Raw Materials 2.1.1. Cement The Ultra-Tech 53 Grade Ordinary Portland Cement (OPC) which complies with IS: 12269-1987is used in the present study. The physical and chemical properties are given in Table 1. 456
  • 3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME Table 1 Properties of 53 Grade OPC Sl.No. Particulars Test Results IS 12269 Requirement Chemical Properties: CaO - 0.7SO3 0.80 min 1 0.87 1.20 max 2.8 SiO2 + 1.2Al2O3 + 0.65 Fe2O3 1.02 Max Lime Saturation Factor (%) 2 TriCalcium silicate (C3S) 45.38% - 3 DiCalcium silicate (C2S) 27.06% - 4 TriCalcium aluminate (C3A) 7.04% - 5 Tetra Calcium Aluminoferrate (C4AF) 13.44% - 6 Al2O3 / Fe2O3 1.20 0.66 min 7 Insoluble Residue (% by mass) 2.25 5.00 max 8 Magnesia (% by mass) 1.0 6.00 max 9 Sulphuric Anhydride (% by mass) 2.01 3.00 max 10 Total Loss on Ignition (% by mass) 1.8 4.00 max 11 Total Chlorides (% by mass) 0.016 0.10 max Performance Improver: 2.5 12 Limestone (%) 2.4 5 max Fly ash (%) Physical Properties: 13 Fineness (Specific surface) (m2/kg) 294 225 min 14 Setting time (min) a. Initial 160 30 b. Final 255 600 15 Soundness test a. By Le Chatelier (mm) 1.0 10.0 max b. By Autoclave (%) 0.090 0.8 % max 16 Compressive strength (MPa) a. 3 days 37.0 27.0 min b. 7 days 48.8 37.0 min c. 28 days 68.8 53.0 min 2.1.2. Ultrafine Powders The Silica fume – 945 D from Elkem India Ltd. which complies with ASTM C 1240 –95a and IS:15388-2003 is used in the study. It is in grey powder form which contains latentlyreactive silicon dioxide and no chlorides or other potentially corrosive substances. Thephysical and chemical properties are mentioned in Table 2. Quartz Powder - The crushed quartz with particle size ranging from 10 µm to 45 µm isused. The specific gravity of quartz powder is 2.6 457
  • 4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME Table 2 Physical and chemical properties of silica fume Sl. No. Properties 1 Form Ultra fine amorphous powder 2 Colour Grey 3 Specific gravity 2.2 4 Bulk Density 700 kg/m3 Densified 5 Specific surface 25 m2/g 6 Particle size 15 µm 7 Sio2 90% 8 H2 O 1% 2.1.3. Aggregate The fine silica sand is the large sized aggregate in RPC. It is yellowish-white high puritysilica sand. The particle size of sand is 150 µm – 600 µm. The particle distribution graph ofall fine materials is shown in Fig.1 Particle size distribution graph 100.0 90.0 80.0 Percentage passing 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0.001 0.010 0.100 1.000 Sand 10.000 Cement Particle size (mm) Quartz Powder Fig. 1 Partical distribution graph of fine materials 2.1.4. Superplasticizer The very low w/b ratio required for RPC can be achieved with use of superplasticizer(SP) to obtain good workability. In this study, the 2nd generation of super plasticizer calledGlenium B-276 Surtec from BASF India Ltd. was used. It is an extremely high range water-reducing agent which meets the requirements of IS: 9103-1999. The properties ofsuperplasticizer are given in Table 3. 458
  • 5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308 (Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME Table 3 Properties of Superplasticizer Sl. Properties Glenium B-276 No. 1 Type of S.P. Polycarboxylate polymer 2 Appearance Dark brown 3 pH Value 6 4 Sp.Gravity 1.2 5 Solid content 40% 6 Recommended dosage 0.3 to 1.2% 2.2. Experimental Procedures 2.2.1 Mix Proportioning To study the influence of the constituent materials, 14 different proportions were considered by varying water-binder ratio, silica fume and quartz powder content. Cement of quantity 900 kg/m3 was kept constant for all the mixes. The water-binder ratio of the mixes varied from 0.16 to 0.24. Silica fume was added by 15 to 25 percent by weight of cement. 20 percent of quartz powder by weight of cement was also added for few mixes. Superplasticizer dosage varied from 1 to 4 percent for all the mixes. Detailed mix proportioning is mentioned in Table 4. Table 4 Proportioning of RPC mixesM i x TM1 TM2 TM3 TM4 TM5 TM6 TM7 TM8 TM9 TM10 TM11 TM12 TM13 TM14Material 15% silica fume 20 % silica fume 25% Silica fume 15% Silica fume + 20% Quartz PowderCement 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Silica 0.15 0.15 0.15 0.15 0.15 0.20 0.20 0.20 0.25 0.25 0.25 0.15 0.15 0.15 fume Quartz - - - - - - - - - - - 0.2 0.2 0.2 powder Sand 1.33 1.28 1.24 1.19 1.15 1.16 1.11 0.91 0.98 0.98 0.92 0.82 0.82 0.82 W/B 0.16 0.18 0.20 0.22 0.24 0.20 0.22 0.24 0.20 0.22 0.24 0.18 0.2 0.22 ratioSP in % 3 2.5 2 1.5 1 3 2.5 2 4 3 2 3 2.5 2Curing Water curing at room temperature and steam curing at 900c for 48 hours.regime 2.2.2 Mixing Procedure The high speed mortar mixer is used to mix the ingredients of RPC. The mixing sequence is as follows: 1. Dry mixing the powders (including cement, silica fume, quartz powder and silica sand) for about 3 minutes with a low speed of about 140 rpm. 2. Addition of sixty percentage volume of water and mix for about 3 minutes with a higher speed of about 285 rpm. 3. Addition of the remaining water and superplasticizer, and mixed for about 10 minutes with a higher speed of about 285 rpm. 459
  • 6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME 2.2.3 Sample Preparation and Curing For each batch of concrete, 100 x 100 x 100 mm cubes were cast to evaluate compressive strength(IS:10086-1999). The specimens were cured at both normal temperature for 28 days and at 90° C for48 hours, remaining 26 days at normal temperature. 2.2.4 Testing Three cube specimens were cast and tested with each RPC mix proportion to evaluatecompressive strength at 7 and 28 days. All tests were carried out using compression testing machine.3. RESULTS AND DISCUSSION Arriving at optimal composition with locally available materials is important to achieve the bestoverall performance of RPC. Hence, the effects of several parameters on compressive strength wereinvestigated which include water-to-binder ratio, superplasticizer dosage, different percentage ofsilica fume, with and without quartz powder and curing regime. During the study it was observed thatthe mixes appeared to be very sensitive to any variation of the chemical composition of the binders orparticle size distribution of the fillers. As there are no standard guidelines for the mix design of RPC,literature was referred to design the mixes. The silica fume content was varied from 15 to 25 percentby weight of cement to find the optimum percentage of silica fume in the production of RPC. Tostudy the influence of addition of quartz powder to RPC, the RPC mixes were also designed withaddition of quartz powder by 20 percent by weight of cement. 3.1. Density of RPC Specimens The density of all the specimens recorded varied between 23.3 – 24.7 kN/m3. 3.2. Effect of Water-to-Binder Ratio on Compressive Strength of RPC The strength of concrete is very much dependent upon the hydration reaction in which water playsa critical role, particularly the amount of water used. The effect of w/b ratio on compressive strengthunder various curing ages is shown in Fig. 2. The result demonstrates that an optimal w/b ratio thatgives the highest compressive strength of RPC in the present study is 0.2. The reduction in strength atlower w/b ratio may be due to the lack of adequate amount of mixing water in RPC to ensure adequatecompaction and proper hydration to occur. Effect of water-to-binder ratio on compressive strength of RPCFig. 2 Effect 140 of 128 water- 120 120 Compressive Strength N/mm2 116 to- 110 112 binder 100 Avg. 94 ratio 80 Compressive strength at 7 days on 72 70 69 66 60 40 Avg. 20 Compressive strength at 28 days 0 WB.-0.22 WB.-0.24 WB-0.16 WB-0.18 WB-0.20 compressive strength of RPC 460
  • 7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME Beyond this optimal w/b ratio of 0.2, it was found that compressive strength decreaseswith increasing w/b ratios. This may be because of more water which is susceptible toentraining air bubbles due to the folding action of the mixing process. As a result, more voidsare left in the matrix which increase the porosity and thus considerably reduce thecompressive strength. The compressive strengths of all mix proportions at 7 and 28 days aretabulated in Table 5. Table 5 Compressive strength of RPC with Glenium B- 276 Normal Curing at 27oc Accelerated Curing at 90 oc for 48 hoursSample Compressive Compressive Compressive Compressive no strength at 7 days strength at 28 strength at 7 days strength at 28 N/mm2 days N/mm2 days N/mm2 N/mm2 TM-1 72 116 81 124 TM-2 70 120 83 132 TM-3 94 128 99 138 TM-4 69 110 78 121 TM-5 66 112 76 119 TM-6 62 93 - - TM-7 58 95 - - TM-8 56 87 - - TM-9 61 96 - -TM-10 55 90 - -TM-11 57 85TM-12 88 112 94 138TM-13 91 117 105 146TM-14 85 109 89 122 3.3 Effect of Silica Fume Percentage on Compressive Strength of RPCThe effect of varying percentage of silica fume on the compressive strength of RPC mix isdemonstrated in Fig. 3. It is observed that the compressive strength tends to decrease as thesilica fume dosage increases. The highest compressive strength was observed for addition of15% silica fume. The compressive strength is seen to fluctuate in the range of 15 % to 25% ofsilica fume regardless of water/binder ratio. As silica fume content increases, mix requiresmore superplasticizer to disperse in fresh concrete. 461
  • 8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME Effect of Silica fume on Compressive strength 140 130 Compressive strength N/mm2 120 110 100 W/B 0.2 W/B 0.22 90 W/B 0.24 80 70 60 15% 20% 25% % Silica fume Fig. 3 Effect of silica fume on compressive strength of RPC 3.4 Effect of Addition of Quartz Powder From the literature it is learnt that, hydrated cement alone cannot help to elevate the strength ofRPC, but other finer materials also contribute marginally. Quartz powder improves the filler effect inRPC mix. As shown in Fig. 4 the addition of quartz powder produce the better result underaccelerated curing condition than that of normal curing condition. The results show that the additionof quartz powder increases the compressive strength by 20% under the accelerated curing condition.This is possible due to increased proportion of hard, fine fillers that enhance the packing density andpore filling action. Effect of curing regime on addtion of quartz powder 160 146 138 140 122 117 120 112 Avg. Compressive strength a t 109 105 7 da ys for norma l curing Compressive strengthN/mm2 100 94 Avg. Compressive strength a t 91 89 88 28 days for norma l curing 85 80 Avg. Compressive strength a t 7 da ys for a ccelera ted curing 60 Avg. Compressive strength a t 28 days for a ccelera ted curing 40 20 0 TM-12 TM-13 TM-14 Fig. 4 The effect of Quartz powder on compressive strength of RPC 462
  • 9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEME 3.5 Influence of Curing Regime An adequate supply of moisture is necessary to ensure that hydration is sufficient toreduce the porosity to a level such that the desired strength can be attained. The effect ofcuring regime on compressive strength under various curing ages is shown in Fig. 5. Twocuring methods were exercised, one with normal water curing at 27ºC, and other at 90ºC hotwater curing for 48 hours. The compressive strength increased by 10% when cured in hotwater as compared to normal curing. This indicates that curing temperature has a significanteffect on the early strength development of RPC. The increased strength is due to the rapidhydration of cement at higher curing temperatures of 90°C compared to that of 27°C.Moreover, the pozzolonic reactions are also accelerated by the higher curing temperatures. Effect of curing regime 160 146 138 138 140 132 128 124 120 121 122 116 119 117 Compressive strength Mpa. 120 110 112 112 109 100 28 days compressive strength of nornal curing 80 60 40 28 days compressive strength of accelerataed 20 curing 0 T-1 T-2 T-3 T-4 T-5 T-12 T-13 T-14 Specimen Fig. 5 Effect of curing regime4. CONCLUSIONS From the present study the following conclusions may be drawn;1. During the production process, it was found that an extended mixing time up to 20-30 min. is required to obtain a consistent and homogeneous mix.2. The maximum compressive strength of RPC obtained in the present study is 146 MPa at w/b ratio of 0.2 with accelerated curing.3. In the production of RPC the optimum percentage addition of silica fume is found to be 15% (by weight of cement) with available superplasticizer.4. The addition of quartz powder increases the compressive strength of RPC up to 20%5. The high temperature curing is essential for RPC to achieve higher strength. It increases the compressive strength up to 10% when compared with normal curing. 463
  • 10. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 3, Issue 2, July- December (2012), © IAEMEACKNOWLEDGEMENTS The authors would like to sincerely thank Mr. Nagesh Chitari for preparing thespecimens and helping to conduct the relevant tests. This research was funded by theVisveswaraya Technological University, Belauam, Karnataka, India through VTU ResearchGrant Scheme.REFERENCES1. Richard P., Cheyrezy M., Composition of Reactive Powder Concretes, Cement and Concrete Research, Vol. 25, No. 7, pp. 1501-1511, 1995.2. Gilliland Scott K., Reactive Powder Concrete (RPC), A New Material for Pre-stressed Concrete Bridge Girders, Building an International Community of structural Engineers, pp. 125-132, 2007.3. Cheyrezy M. et al., Microstructural Analysis of RPC, Cement and Concrete Research, Vol. 25, No. 7, pp. 1491-1500, 1995.4. Reda M.M. et al., Microstructural Investigation of innovative UHPC, Cement and Concrete Research, Vol. 29, pp. 323-329, 1999.5. Gowripalan N. et al., Reactive powder concrete for precast structural concrete, 21st Biennial conference concrete institute of Australia, Brisbane, pp. 99- 108, 2003.6. Bonneau O. et al., Reactive Powder Concretes: from Theory to Practice, Concrete International, Vol. 18, No. 4, pp. 47-49, 1996.7. Hassan A. and Makoto Kawakami, Steel-Free composite slabs made of reactive powder materials and fiber reinforced concrete, ACI structural Journal, Vol. 102, No. 5, pp. 709- 718, 2005.8. Harish K V et al., Role of ingredients and of curing regime in ultra high strength powder concretes, Journal of Structural Engineering, Vol. 34, No. 6, pp. 421-428, 2008.9. Dili A S., Manu Santhanam, Investigation on reactive Powder Concrete: A developing ultra high- strength technology, The Indian Concrete Journal, Vol. 78, No. 4, pp. 33-38, 2004.10. M.N.Bajad, C.D.Modhera and A.K.Desai, “Influence Of A Fine Glass Powder On Strength Of Concrete Subjected To Chloride Attack” International Journal of Civil Engineering & Technology (IJCIET), Volume2, Issue2, 2011, pp. 1 - 12, Published by IAEME11. Vidula S. Sohoni and Dr.M.R.Shiyekar, “Concrete–Steel Composite Beams Of A Framed Structure For Enhancement In Earthquake Resistance” International Journal of Civil Engineering & Technology (IJCIET), Volume3, Issue1, 2012, pp. 99 - 110, Published by IAEME12. K. Sasiekalaa And R. Malathy, “Flexural Performance Of Ferrocement Laminates Containing Silicafume And Fly Ash Reinforced With Chicken Mesh” International Journal of Civil Engineering & Technology (IJCIET), Volume3, Issue2, 2012, pp. 130 - 143, Published by IAEME 464

×