Addition of silica fume and fly ash to enhance the compressive and flexural strength of concrete

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1 Addition of silica fume and fly ash to enhance the compressive and flexural strength of concrete Alok kumar, Monendra singh 2,Dheeraj 3 Kunal sobhawat 4,Krishan joshi 5,Dinesh 6 Asst. Professor, Dept. of Civil Engg. Poornima Institute of Engineering and Technology 2, 3, 4, 5 B.Tech. Students, Dept. of Civil Engg., Poornima Institute of Engineering and Technology Jaipur India Abstract: Now a days we required to make the project economic. In the project the cost of material play vital role. Mainly cost of cement is so high so every person cannot afford it.to attain high performance concrete on low cost we can add fly ash and silica fume in the concrete mixture. It make the project economic and ecofriendly and this work mainly deals with the strength such as compressive split tensile and flexural strength. High performance concrete (HPC) is the mixture of different- different constituents which were cast and tested with different level of silica 2.5, 5, 7.5 and fly ash 0, 5, 20 by weight of cement and after each trial super plasticizer (lingo sulphonate) add to attain fix range of slump with desired degree of workability with constant water cement ratio is 0.43.Specimen was cast and cured in water bath for 7, 28 days. After determined the density of cube the cube are tested of compressive strength in compressive testing machine (CTM).By addition of silica fume and fly ash the density of concrete is increased.in this study we add 0-7.5%of silica fume and 0-20% of fly ash so we can develop high strength concrete at low cost as well as the problem of disposal of by product silica fume and fly ash can be resolve and project became ecofriendly. Keyword: silica fume high performance concrete, silica fume, fly ash, water cement ratio, flexural strength, compressive strength INTRODUCTION: Generally high grade cement is use in high grade concrete which fulfil the requirement of high grade concrete but by using the high grade cement the cost of the project increases. This problem can be resolve by cheap admixture having cementious property. For this purpose we are adding silica fume and fly ash in M-25 grade concrete. Fly ash and silica fume both are by product. Silica fume is amorphous material. It is obtain by silicon and ferro silicon alloy production. It is contain spherical alloy having average diameter 50nm.Whereas fly ash is by product of coal combustion. It is generally captured by electrostatic precipitator or other practical filtration equipment. Generally the fly ash and silica fume don t have any cementious property but when we use it with cement than it show cementious property because the silica of the pozzolanic material (fly ash and silica fume) react with the calcium hydroxide which is released by the hydration of cement and formed calcium silicate hydrate(c-s-h) which is helpful to improve strength and other mechanical property concrete. By increasing the grade of concrete the water cement ratio is decreases as well as the cement percentage is increases. High performance concrete denotes good abrasion, impact and cavitation resistance. By adding of silica fume the concrete become resistant sulphate attack freezing and thawing and alkali silica reactivity. SILICA FUME REACTION: Pozzolanic effect When water is added to OPC (ordinary Portland cement), hydration occur forming two products, as shown below: OPC + H 2 O CSH (Calcium silicate hydrate) + Ca (OH) 2 In the presence of micro-silica, the silicon dioxide from the micro-silica will react with the calcium hydroxide to produce more aggregate binding CSH as follows:- Ca (OH) 2 + SiO 2 +H 2 O CSH The reaction reduces the amount of calcium hydroxide in the concrete. The weaker calcium hydroxide does not contribute to strength. When combine with carbon dioxide, it forms a soluble salt which will leach through the concrete causing efflorescence, a familiar architectural problem. Concrete is also more vulnerable to sulphate attack, chemical attack and adverse alkali-aggregate reactions when high amounts of calcium hydroxide is present in concrete. LITERATURE REVIEW There are many studies which have been concerned or taken in literature on behavior and performance of concrete containing ground-granulated blast-furnace slag by means of partial addition. We have studied on Compressive strength of high performance concrete with the addition of cement with Ground-granulated blast-furnace slag and Fly ash, and also with natural sand to manufactured sand In this study the effect ISSN: Page 54

2 of Ground-granulated blast-furnace slag as a supplementary cementing material and filling material on the strength of concrete was investigated. The maximum compressive strength of concrete is achieved by using Ground-granulated blast-furnace slag 0% & Fly Ash 30% The addition of Ground-granulated blast-furnace slag increases the self-compatibility characteristics like filling ability, passing ability and resistance to segregation. The relative cost of Ground-granulated blast-furnace slag is cheaper than cement hence it is also economic with higher strength. Saoji M.S. Pawar, A.C. have studied the Effect of Groundgranulated blast-furnace slag on Self Compacting Concrete The study explores the use of the Ground-granulated blastfurnace slag powder to increase the amount of the fines and hence achieve self compatibility. The study focuses on comparison of the properties of SCC with fly ash and Ground-granulated blast-furnace slag to that of standard one. Deval Soni, Suhasini Kulkarni and Vilin Parekh (203) have investigated the experimental study on high-performance concrete, with mixing of Ground-granulated blast-furnace slag and fly ash by means of partial replacement of Groundgranulated blast-furnace slag203 and fly ash by weight of cement. They get maximum compressive & flexural strength when cement is replaced by 24% (i.e. 8% Ground-granulated blast-furnace slag & 6% fly ash). Yatin H Patel, P.J.Patel, Prof. Jignesh M Patel, Dr. H S Patel (203) have investigated on durability of high performance concrete with Ground-granulated blast-furnace slag and fly ash. On this study they investigate the performance of concrete mixture in terms of compressive strength, In addition of Ground-granulated blast-furnace slag and fly ash from given mix proportion concluded that compressive strength achieved by using Ground-granulated blast-furnace slag (8%) + Fly Ash (20% is higher. Their result also shows that concrete incorporating Groundgranulated blast-furnace slag and fly ash have higher compressive strength and Ground-granulated blast-furnace slag enhanced the durability of concretes and reduced the chloride diffusion. Saurav, Ashok Kumar Gupta (204) have investigated on experimental study of strength relationship of concrete cube and concrete cylinder using ultrafine slag Ground-granulated blast-furnace slag and have shown the comparison between cubical strength and cylindrical strength of normal concrete and with partial replacement of cement with ultra-fine slag (Ground-granulated blast-furnace slag) and varies at 3%, 5%, 7%, 0%, 3%, 5% & 8 %. They found the result is higher compressive cube strength and compressive cylinder strength at 3% replacement of cement with ultra-fine slag. MATERIAL CEMENT: Opc according to code AGGREGATE: it is cover 70-80% part of whole volume. It is consists of river sand fine aggregate and coarse aggregate. The sand should be pass through.8mm sieve And having fineness modulus and specific gravity 3.05&2.35 respectively. The sand should be free from impurities like organic material or clay coarse aggregate should be pass through 2.5mm and retain on 4.75mm is taken the fineness modulus and specific gravity 4.03 & 2.88 respectively according to IS code provision. WATER: The water which is use in the experiment should be free from impurities like acids, alkalis organic waste and suspended solid, According to code IS the potable water having ph 7 is suitable for this. FLY ASH: Fly ash (FA) obtained from Thermal power plant, Kota district, Rajasthan state, India confirming to IS: used in mineral admixture in dry powder form. The physical and chemical properties were given Table S. No Parameter Quantity (% wt.) Silicon Dioxide(SiO 2 ) Alumina(Al 2 O 3 ) Iron oxide(fe 2 O 3 ) Calcium oxide (CaO) Magnesium (MgO) oxide Sulphur tri oxide (SO 3 ).34 7 Sodium oxide (Na 2 O) Potassium oxide (K 2 O) Loss On Ignition % by mass SILICA FUME: The Silica fume obtained from the M/s ELKEM Pvt Ltd, Bombay confirming to ASTM C240 was ISSN: Page 55

3 used for this study. The physical and chemical properties were given in Table. (silica fume) CHEMICAL ADMIXTURE: Super plasticizers (SP) or high range water reducing admixtures are an essential component of HPC. Lingo sulphonate was used as super plasticizer (conforming to IS: 903:999). MIX PRPORTION AND CASTIN OF HPC: Numbers of attempts were made in laboratory to get optimum mix proportion to produce M-25 grade HPC without segregation and bleeding with satisfying the properties both in fresh and hardened states. For this study totally seven HPC mixes were prepared with a water to binder (W/(C+SF+FA) ratio of 0.43 with % of super plasticizer. The HPC was mixed for 5 minutes in laboratory drum mixer. For all mixes, nine cube specimens of 50mm size were cast from each mix for compressive strength testing. Three cylindrical specimens of 50mm diameter and 300mm height were also cast from each mix for determining the splitting tensile strength. Before compression test, all specimens were tried and used for ultrasonic pulse velocity test. After casting, all the specimens were left covered in the casting room for 24 hours. The specimens were unmolded and transferred to moist curing room until the time of testing. TEST & OBSERVATION COMPESSIVE STRENGTH: Compressive strength test was conducted in compressive testing machine on cubes of size 50*50*50 mm (Compressive Testing Machine) Compressive strength of M-25 Average For Mix (Cement Compressive + Silica Strength M-25 Fume + Fly (N/mm 2 ) ash) 28 7 Days Days OPC+Fly Fume (00+0+0) Fume ( ) Fume (00+5+5) Fume ( ) ISSN: Page 56

4 SSRG International Journal of Civil Engineering (SSRG-IJCE) volume 3 Issue 7 July Average For Comp. Strength N/mm z SPLIT TENSILE STRENGTH: This test is conducted in universal testing machine on cylinders of size 50*300 mm Split tensilt strength of M Mix (Cement + Silica Fume + Fly ash) Average For Splitting Tensile strength M- 25 (N/mm 2 ) 28 Days OPC+Fly Fume (00+0+0).98 Fume ( ) 2.04 Fume (00+5+5) 2.2 Fume ( ) Average For Spliting 2.9 Tensile.8 Strength N/mm 2 28 days FLEXURAL STRENGTH: This test is conducted in universal testing machine on beam of size 00*00*500 mm (Splitting Tensile Strength Test) Flexural strength Test (for single loading) ISSN: Page 57

5 Flexural strength of M-25 Mix (Cement + Average For Flexural Silica Fume + Fly Strength M-25 (N/mm 2 ) ash) OPC+Fly Ash+ Silica Fume 4.95 (00+0+0) 2 Silica Fume 5.09 ( ) 3 Silica Fume 5.3 (00+5+5) 4 Silica Fume 5.79 ( ) Average For Flexural 5 Strength 4.5 N/mm 2 28 days Mixing of Ground-granulated blast-furnace slag and Fly ash Perspex - Indian Journal of Research, Is , volume 3, issue 4, pp , May Saurav and Ashok Kumar Gupta Experimental Study Of Strength Relationship Of Concrete Cube And Concrete Cylinder Using Ultrafine Slag Ground-granulated blastfurnace slag International Journal of Scientific & Engineering Research, ISSN , Volume 5, Issue 5,, pp , May IS: , Plain and Reinforced Concrete - Code of Practice Bureau of Indian Standards, New Delhi, India. 4. IS: (Part I to Part III), Indian Standards Method of Test for Aggregate for Concrete, Bureau of Indian Standards, New Delhi, India. 5. IS: , Indian Standard Specification for coarse and fine aggregates from Natural Source for Concrete, Bureau of Indian Standards, New Delhi, India. 6. IS: , Specifications for 43-Grade Portland Cement, Bureau of Indian Standards, New Delhi, India. 7. IS: , Guidelines for Concrete Mix Design, Bureau of Indian Standards, New Delhi, India.. 8. IS: , Indian Standard Code of Practice-Methods of Test for Strength of Concrete, Bureau of Indian Standards, New Delhi, India. RESULTS AND DISCUSSION In this test we add fly ash and silica fume to enhance the strength of concrete in ratio of silica 0, 2.5, 5, 7.5 and fly ash 0, 0, 5, 20 by the weight of cement. We have performed three test on Concrete mix that was compression test, split tensile test, flexural test. The result of following test given below in the tables 9. IS: , Method of Test Splitting Tensile Strength of Concrete, Bureau of Indian Standards, New Delhi, India. 0. IS: , Specification for Concrete Admixtures Bureau of Indian Standards, New Delhi, India. CONCLUSION & RECOMMENDATION By adding silica fume and fly ash the strength of concrete is increases. At fly ash 7.5% & silica fume 20% of cement we obtain M-30 concrete in M-25 concrete design mix. The future aspect of the project is REFERENCE. Deval Soni, Suhasini Kulkarni and Vilin Parekh Experimental Study on High-Performance Concrete, with ISSN: Page 58