EXPERIMENTAL STUDY OF FACTORS INFLUENCING COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE

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1 EXPERIMENTAL STUDY OF FACTORS INFLUENCING COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE Ajay Sharma 1, Jund Ahmad 2 1 PG Studnt, Structural Enginring, Intgral Univrsity, Uttar Pradsh, India 2 Assistant profssor, Dpartmnt Of Civil Enginring, Intgral Univrsity, Uttar Pradsh, India *** Abstract - Manufactur of Portland cmnt producs larg of volums of carbon dioxid and othr gass. Rlasing ths gass causs atmosphric pollution and subsqunt nvironmntal dgradation. Finding a suitabl altrnativ solution to mitigat th nvironmntal dgradation causd by using Portland cmnt is vry important for nvironmntal sustainability. On th othr sid, fly ash is th wast matrial of coal basd thrmal powr plant, availabl abundantly but pos disposal problm. Thr ar nvironmntal bnfits in rducing th us of Portland cmnt in concrt, and using a cmntitious matrial, such as fly ash. Gopolymr concrt is nw sustainabl concrt which is manufacturd by rplacing cmnt 100% with procssd fly ash which is chmically activatd by alkalin solutions mad from sodium silicat (Na2SiO3) and sodium hydroxid (NaOH). This thsis prsnts th ffct of svral factors lik alkalin liquid to fly ash ratio, molarity of NaOH, curing hours and curing tmpratur on th comprssiv strngth of fly ash basd gopolymr concrt. Fly ash is takn as th basic matrial to dvlop th gopolymr concrt and it is activatd by th alkalin solution of sodium silicat and sodium hydroxid. Th tst variabls wr molaritis of sodium hydroxid (NaOH) M, 4M, M, and M, ratio of NaOH to sodium silicat (Na2SiO3) 2.5, alkalin liquid to fly ash ratio 0.35, 0.40, 0.45 and 0.50 wr usd in th prsnt study. Th xprimnt wr also conductd on GPC cubs for curing tmpratur of 75 C, 90 C and 105 C with curing priod of, and 24 hours by adopting hot ovn curing mthod. Th tst rsult indicatd that th comprssiv strngth incrass with incras in molarity of NaOH but it dcrass with incrass in watr contnt. It is also absorbd that comprssiv strngth is rmarkably affctd by th curing hours and curing tmpratur. Whn curing tmpratur is incrass, th comprssiv strngth is also incrass and it rquirs lss curing priod to gain th highr strngth. 1.INTRODUCTION 1.1 Gnral Production of cmnt is on of th major contributors to th mission of grn-hous gasss lik carbon dioxid. Day by day th World s Portland cmnt production incrass with th incrasing dmand of construction industry. Cmnt is th main ingrdint for th production of concrt. But th production of cmnt rquirs larg amount of raw matrial. During th production of cmnt burning of lim ston tak plac which rsults in mission of carbon dioxid (CO2) gas into th atmosphr. Thr ar two diffrnt sourcs of CO2 mission during cmnt production. Combustion of fossil fuls to oprat th rotary kiln is th largst sourc and othr on is th chmical procss of burning limston. In 1995 th production of cmnt was 1.5 billion tons which gos on incrasing up to 2.2 billion tons in On ton of production of cmnt causs on ton of mission of CO2 into th atmosphr. It is stimatd that th mission of carbon dioxid du to cmnt production to b narly about 7% of th total production of carbon dioxid, which mak rquird to go for othr grnr altrnativ bindr from Portland cmnt [1]. Fly ash is th wast rsidu that rsults from th combustion of coal in thrmal powr station is availabl at larg scal all ovr th world. In India mor than 100 million tons of fly ash is producd annually. Out of this, only 17 20% is utilizd ithr in concrt or in stabilization of soil. Most of th fly ash is disposd off as a wast matrial that covs svral hctors of valuabl land. As fly ash is light in wight and asily flis, this crats svr halth problms lik asthma, bronchitis, and so forth. Thr ar nvironmntal bnfits in rducing th us of Portland cmnt in concrt, and using a by-product matrial, such as fly ash as a substitut. With silicon and aluminium as th main constitunts, fly ash has grat potntial as a cmnt rplacing matrial in concrt. For vry ton of fly ash usd in plac of Portland cmnt savs about a ton of carbon dioxid mission to th atmosphr [2]. Davidovits proposd a nw trm gopolymr in 1978 to rprsnt th minral polymrs rsulting from gochmistry. Gopolymrs ar mmbrs of th family of inorganic polymrs in which th minral molculs ar linkd with covalnt bond. Gopolymrs ar producd by sourc matrials or by-product of gological origin that is rich in silica and alumina lik fly-ash whn ract with alkalin solution at lvatd tmpratur. Th chmical raction that taks plac in this cas is polymrization, so this bindr is calld gopolymr. Gopolymr concrt is a nw typ of concrt in which cmnt is fully rplacd by th pozzolanic matrials that is rich in Silicon (Si) and Aluminium (Al) lik fly ash. It is activatd by highly alkalin liquids to produc th bindr which binds th aggrgats in concrt whn subjctd to lvatd tmpratur. Th 2017, IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1306

2 concrt mad with such industrial wast is co-frindly and so it is calld as Grn concrt. Th chmical composition of th gopolymr matrial is similar to zolitic matrials, but th microstructur is irrgular. Th polymrization procss involvs a fast chmical raction undr alkalin condition on Si-Al minrals, thos rsults in a thr-dimnsional polymric chain and ring structur xisting of Si-O-Al-O bonds. Poly (sialats) as th rsultd matrial has th mpirical formula as blow: Mn [-(SiO2)z-AlO2]n. wh2o Whr: M = th alkalin lmnt or cation such as potassium, sodium or calcium n = th dgr of polycondnsation or polymrisation z = 1,2,3 or highr Th main concpt bhind this gopolymr matrial is th polymrization of th Si-O-Al-O bond which dvlops whn Al-Si sourc matrials lik Fly ash is mixd with alkalin liquids. Th gopolymr can b on of ths basic form: Poly (sialat), [-Si-O-Al-O-] Poly (sialat-siloxo), [-Si-O-Al-O-Si-O-] Poly (sialat-disiloxo), [-Si-O-Al-O-Si-O-Si-O-] Th schmatic formation of gopolymr matrial can b shown by quations (1) and (2). n( Si2O5, Al2O2 ) + 2nSiO2 + 4nH2O +NaOH/KOH (Si-Al matrials) Na+, K+ + n(oh)3-si-o-al--o-si-(oh (OH)2 (Gopolymr prcursor) [1] n(oh)3-si-o-al--o-si-(oh)3 + NaOH/KOH (OH)2 ( Na+, K+)-(-Si-O-Al--O-Si-O-) + 4nH2O O O O ( Gopolymr Backbon) [2] Th xact mchanism of stting and hardning of th gopolymr matrial is not clar. Howvr, most proposd mchanism consists th chmical raction may compris th following stps: 1. Dissolution of Si and Al atoms from th sourc matrial through th action of hydroxid ions. 3. Stting or polymrisation of monomrs into polymric structurs [3]. Watr is rlasd during th chmical raction that occurs in th formation of gopolymrs. This watr, rlasd from th gopolymr concrt during th rst priod, ovn curing and furthr drying priods, lavs bhind discontinuous nano-pors in th concrt, which provid bnfits to th prformanc of gopolymr concrt. Th watr in a gopolymr mixtur, plays no rol in th chmical raction that taks plac; it provids th workability to th mixtur during handling [4] 1.2 Constitunts of Gopolymr Concrt Thr ar two main constitunts of Gopolymrs, namly th sourc matrials and th alkalin liquids. By-product matrials such as fly ash, silica fum, slag, ric husk ash, GGBS, rd mud, tc can b usd as sourc matrials. Th most common alkalin liquid usd in gopolymr concrt is a combination of sodium hydroxid or potassium hydroxid and sodium silicat or potassium silicat. It is important that th alkalin liquid is prpard by mixing both th solutions togthr at last 24 hours prior to us. Th mass of NaOH solids in a solution dpnd on th molarity of th solution. 1.3 Advantags of Go-Polymr Concrt High arly comprssiv strngth gain Good abrasion rsistanc Rapid controllabl stting and hardning Fir rsistanc up to 1000 dgr cntigrad and no mission of toxic fums whn hatd High lvl of rsistanc to a rang of diffrnt acids and salt solutions Low thrmal conductivity and low shrinkag Imprmabl lik normal OPC concrt Bld fr High surfac dfinition that rplicats mould pattrns [5]. 1.4 Objctiv of th Prsnt Study To study th ffct of factors lik, alkalin liquid to fly ash ratio, curing hour and curing tmpratur that affcts th comprssiv strngth of fly ash basd gopolymr concrt. 2. Transportation or orintation or condnsation of prcursor ions into monomrs. 2017, IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1307

3 2 EXPERIMENTAL PROGRAMME 2.1 Matrials Usd A. Fly Ash In this study, fly ash (ASTM Class F) obtaind from Rosa Thrmal Powr Station Shahajahanpur was usd. Th chmical and physical proprtis of fly ash shown blow in tabl 2.1 and 2.2 rspctivly. Tabl-1: Chmical Proprtis of Fly Ash Charactristics Silicon dioxid (SiO2) Alumina (Al2O3) Iron oxid (F2O3) Calcium oxid (CaO) Magnsium Oxid (MgO) Sulphur trioxid (SO3) Sodium oxid (Na2O) Potassium oxid (K2O) Titanium (TiO2) Obsrvd Valu (%) Rang Spcifid for Class- F Fly ash (as pr ASTM C-6) Tabl-2: Physical Proprtis of Fly Ash Charactristics Obsrvd Valu Spcific Gravity 2. Finnss(m2/kg) 340 Lim ractivity(n/mm2) 4.8 Loss on Ignition(% by mass) 0.70 Soundnss by auto-clav 0. mthod B. Alkalin Solution Th combination of sodium silicat to sodium hydroxid was usd as alkalin solution in th prsnt study and th ratio of both was maintaind to 2.5 throughout th study. Th solution was prpard on day prior to b usd. I. Sodium Hydroxid Gnrally NaOH is availabl in markt in pllts or flaks form with 96% to 98% purity whr th cost of th product dpnds on th purity of th matrial. Sodium hydroxid in pllt form was usd in this work of 97% purity. Th solution of NaOH was formd by dissolving it in dionisd watr for th molarity of M, M, M & M. Th NaOH solution was prpard 24 hours bfor casting of spcimns. II. Sodium Silicat Sodium Silicat (Na2SiO3) is also known as watrglass which is availabl in th markt in gl form and also in th solid form. Sodium silicat in gl form was usd in this study having 31% of SiO2, % of Na2O & 55% of H2O. Th ratio of silicon dioxid (SiO2) and sodium oxid (Na2O) in sodium silicat gl is Fig.-1: Sodium Hydroxid Pllts 2.2 Proportioning Dtails Fig.-2: Sodium Silicat Liquid Th gopolymr concrt was mad for sixtn diffrnt mix proportion of fly ash, alkalin solution, fin aggrgat and coars aggrgat with variation in alkalin liquid to fly ash ratio as 0.35, 0.40, 0.45 & 0.50 for molaritis of M, M, M, &M. Tabl-3: dtails of fly ash basd gopolymr Concrt S Alkalin sol./fly ash ratio Fly ash (Kg/m3) , IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1308

4 and 24 hours. Aftr th curing priod, th tst spcimns wr lft in th moulds for at last 5-6 hours in ordr to avoid a major chang in th nvironmntal conditions. Aftr d-moulding, th concrt spcimns wr allowd to bcom air-dry in th laboratory until th day of th comprssiv strngth tsting. Coars aggrgat (Kg/m3) Sodium hydroxid (Kg/m3) Sodium silicat (Kg/m3) Fig.-4: Addition of Alkalin Solution 2.3 ing Casting and of Gopolymr Concrt In th laboratory, th fly ash and th aggrgats was first mixd togthr in dry stat 2-4 minuts to gt homognous mix. Th alkalin solution was mixd with th xtra watr and this liquid componnts wr addd to th mixd aggrgat and th mixing continud usually for anothr - 15 minuts so that binding past covrd all th aggrgats and mixtur bcom homognous and uniform in colour. Th frsh concrt could b handld up to 0 minuts without any sign of stting and without any dgradation in th comprssiv strngth. Aftr th mixing is don, th frsh gopolymr concrt was filld in th moulds in thr layrs with rquird compaction sam as th usual mthods usd in th cas of Portland cmnt concrt and th spcimns ar kpt on a vibrating tabl so that to minimiz amount of voids prsnt in th frsh concrt. Th workability of th frsh concrt was masurd by mans of th convntional slump tst. For th polymrisation procss, th high tmpratur curing is rquird in gopolymr concrt. Th rquird tmpratur may b providd ithr by ovn curing or by stam curing. In th prsnt study, ovn curing was usd. Th GPC cubs wr placd in an ovn for th priod of, Fig.-5: Frsh Gopolymr Concrt Fig.-6: Ovn of GPC Cubs 2017, IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1309

5 2.4 Tsting of Gopolymr Concrt Cubs Th gopolymr hardnd concrt cubs wr tstd for comprssiv strngth. Th comprssiv strngth tst was prformd according to IS-50: Cub spcimns of siz 150mm 150mm 150mm wr prpard for ach mix. Aftr on day of rst priod, thy wr curd in ovn for, & 24 hours and wr dmodd and stord until th day of tsting. For spcimns with unvn surfacs, capping was usd to minimiz th ffct of strss concntration. Th comprssiv strngth rportd is th avrag of thr rsults obtaind from thr idntical cubs. Chart-1: Effct of molarity on comprssiv strngth gopolymr concrt for AL/Fly-ash ratio 0.35 of Tabl-5: strngth for Alkalin solution to fly ash ratio=0.40 Fig.-7: Tsting of GPC Cubs 3. EXPERIMENTAL RESULTS AND DISCUSSION 3.1 Effct of and AL (Alkalin Liquid)/Fly-Ash Ratio on th of GPC Tabl-4: of Alkalin solution to fly ash ratio= days Avrag comp days Avrag comp Chart-2: Effct of molarity on comprssiv strngth of gopolymr concrt for AL/Fly-Ash ratio , IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1310

6 Tabl-6: strngth for Alkalin liquid to fly ash ratio= Tabl-7: strngth for Alkalin liquid to flyash ratio= days Avrag comp Avrag comp Chart-4: Effct of molarity on comprssiv strngth of gopolymr concrt for AL/Fly-ash ratio 0.50 Th rsults indicatd that th comprssiv strngth incrass with incras in molarity of NaOH solution upto M but byond th molarity M, slightly variation in comprssiv strngth is obsrvd for th molarity M. Rsults also show that th comprssiv strngth is incrass with incrmnt in alkalin liquid to fly ash ratio but for ratio valu byond 0.45, slightly dcras in comprssiv strngth is obsrvd. It mans whn this ratio is incrass, th watr contnt in th solution is incrass which affct th comprssiv strngth. 3.2 Effct of Hour and Tmpratur on of GPC Tabl-8: strngth of GPC spcimns at curing tmpratur of 75 C -11 Tmp - ratur ( C) 75 Priod (hours ) 24 Comprssiv Man Comprssiv (MPa Chart-3: Effct of molarity on comprssiv strngth of gopolymr concrt for AL/Fly-ash ratio , IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1311

7 Tabl-10: strngth of GPC spcimns at curing tmpratur of 105 C Tmp- Raptur ( C) Priod (hours ) Comprssiv Man Comprssiv Chart-5: Effct of curing hours on comprssiv strngth of GPC for tmpratur 75 C Tabl-9: strngth of GPC spcimns at curing tmpratur of 90 C Tmpratur ( C) 90 Priod (hours) 24 Man Chart-7: Effct of curing hours on comprssiv strngth of GPC for tmpratur 105 C Th comprssiv strngth of GPC concrt is obsrvd to incrass at curing tmpraturs 75 C and 90 C for, and 24 hr of curing priod, but whn curing is don at 105 C, comprssiv strngth incrasing up to hr of curing, aftr that it start dcrasing. Hnc it is obsrvd that whn curing tmpratur is incrasd, it rquirs lss curing hours to gain sam comprssiv strngth. 3. CONCLUSIONS Basd on th xprimntal work rportd in this study, th following conclusions ar drawn: Chart-6: Effct of curing hours on comprssiv strngth of GPC for tmpratur 90 C 1. strngth of gopolymr concrt is incrass with incras in alkalin solution to fly ash ratio upto 0.45, but at 0.50 th strngth slightly dcrass bcaus of incras in watr contnt prsnt in alkalin solution. 2017, IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 13

8 2. strngth of GPC is also incrass with incras in concntration of NaOH up to M, but for M, thr is no rmarkabl changs in comprssiv strngth but th cost of production is incrass. 3. At 75 C tmpratur, th comprssiv strngth incrass gradually with th incrass in curing priod up to 24 hr. 4. At 90 C tmpratur, th sampls gaind 95 % strngth at hours of curing, byond this curing priod, minor incrmnt in strngth is rcordd. 5. strngth of GPC sampls at 105 C tmpratur crtain incrass up to hours of curing priod but it dcrass whn it curd for 24 hr at 105 C. It has bn obsrvd from th abov discussion that thr ar various paramtrs that affcts th comprssiv strngth of th gopolymr concrt. Thrfor, paramtric study of various factors influncing th comprssiv strngth of th gopolymr concrt is strongly rcommndd first bfor conducting any furthr invstigations rlatd to mchanical proprtis and durability of th gopolymr concrt in ordr to gt th dsirabl bnfits from th furthr invstigations. 3rd Nirma Univrsity Intrnational confrnc on Enginring, 20. [7] Subhash V. Patankar t al Effct of watr-togopolymr bindr ratio on th production of fly ash basd gopolymr concrt Rsarch Scholar, Dpartmnt of Applid Mchanics, Govrnmnt Enginring Collg, Aurangabad, (M.S.) India, [8] Yasir Sofi, Iftkar Gull Study Of Proprtis Of Fly Ash Basd Go Polymr Concrt A Pr Rviwd Intrnational Journal, Vol.3., Issu.1, [9] Raijiwala D.B. Patil H. S. Gopolymr Concrt: A Concrt Of Nxt Dcad JERS/Vol.II/ Issu I/January- March 2011/ [10] Dali Bondar Go-polymr Concrt as a Nw Typ of Sustainabl Construction Matrials third intrnational confrnc on sustainabl construction matrials and tchnologis. [11] Shriram Marath t al A Rviw on and Durability Studis on Gopolymr Concrt Intrnational Journal of Innovativ Rsarch in Scinc, Enginring and Tchnology,Vol. 5, Spcial Issu 9, May 20 ACKNOWLEDGEMENT Author thanks to Asst. Prof. Jund Ahmd and frinds for ncouraging m to work on this topic and thir constant assistant. REFERENCES [1] Shivaji S. Bidw and Ajay A. Haman Effct of diffrnt molaritis of Sodium Hydroxid solution on th of Gopolymr concrt Amrican Journal of Enginring Rsarch (AJER) -ISSN : p- ISSN : Volum-4, 2015, Issu-3, pp [2] Satput Mansh B t al., Effct of Duration and Tmpratur of on of Gopolymr Concrt Intrnational Journal of Enginring and Innovativ Tchnology (IJEIT) Volum 1, Issu 5.May 20. [3] M. M. A. Abdullah t al Mchanism and Chmical Raction of Fly Ash Gopolymr Cmnt- A Rviw Int. J. Pur Appl. Sci. Tchnol., 6(1), 2011, pp [4] Kolli Ramuj and M. Potharaju Dvlopmnt of Low Calcium Flyash Basd Gopolymr Concrt IACSIT Intrnational Journal of Enginring and Tchnology, Vol. 6, 1, Fbruary 20, [5] A.Maria Rajsh, M.Adams Jo, Roy Mammn Study of th Gopolymr Concrt with Alkalin Solution of Varying IOSR Journal of Enginring (IOSRJEN) ISSN (): , ISSN (p): Vol. 04, Issu, Jun. 20, V1 PP [6] Prakash R. Voraa, Urmil V. Davb Paramtric Studis on of Gopolymr Concrt Chmical, Civil and Mchanical Enginring Tracks of 2017, IRJET Impact Factor valu: 5.1 ISO 9001:2008 Crtifid Journal Pag 1313