Fly Ash Based Gpc

8/19/2019 Fly Ash Based Gpc

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International Journal of Emerging Technology and Advanced EngineeringWebsite: www.ijetae.com (I! ""#$%"' I) '$$*:"$$+ ,ertified Journal -olume Issue * January "$*/

ALKALI Activated FLY-ASH Based Geopolymer ConcreteAmmar Motorwala

1 !ineet S"a"

# $avis"an%ar Kamm&la

' (raveena )annapaneni

* (ro+, , B, $ai.iwala

/

1 Department of Applied Mechanics, SVNIT-Surat, Gujarat-3!""#

$ Department of %i&il 'n(ineerin(, IIT-Delhi

3,) Department of %i&il 'n(ineerin(, SVNIT-Surat, Gujarat-3!""#

! Associate *rofessor, Department of Applied Mechanics, SVNIT-Surat, Gujarat-3!""#

Abstract % ,onsidering the increasing demand for

develo0ing alternative construction materials due to the

growing environmental concerns this 0a0er discusses the

feasibility of al1ali activated geo%0olymer concrete as a

future construction material. The main objective of this studyinvolves observation of structural behaviours of the fresh fly

ash%based geo%0olymer concrete understanding the basic

mi2ture 0ro0ortioning of fly ash%based geo%0olymer concrete

and evaluating various economic considerations.

Keywords% Al1ali activated fly%ash based geo%0olymerconstruction material for green building geo%0olymerconcrete eco%friendly construction material low calciumbased geo%0olymer concrete.

9. I )0$2C0I)

Concrete &sa3e aro&nd t"e world is second only towater and rdinary (ortland Cement 4(C5 is

conventionally &sed as t"e primary 6inder to prod&ceconcrete, 0"e environmental iss&es associated wit" t"e prod&ction o+ (C are too many, 0"e cement ind&stry is

"eld responsi6le +or some o+ t"e C# emissions, 0"eamo&nt o+ t"e car6on dio7ide released d&rin3 t"eman&+act&rin3 o+ (C d&e to t"e calcination o+ limestoneand com6&stion o+ +ossil +&el is in t"e order o+ one ton +or every ton o+ (C prod&ced, In addition t"e e7tent o+ ener3y re8&ired to prod&ce (C is only ne7t to steel andal&mini&m,

0"e demand +or (ortland cement is increasin3 day 6yday and "ence e++orts are 6ein3 made in t"e constr&ctionind&stry to address t"is 6y &tilisin3 s&pplementary

materials and developin3 alternative 6inders in concrete9t"e application o+ 3eo-polymer tec"nolo3y is one s&c"alternative, 0"e a6&ndant availa6ility o+ +ly as" worldwidecreates opport&nity to &tilise t"is 6y-prod&ct o+ 6&rnin3coal as a s&6stit&te +or (C to man&+act&re concrete,:"en &sed as a partial replacement o+ (C in t"e presence o+ water and in am6ient temperat&re +ly as"reacts wit" t"e calci&m "ydro7ide d&rin3 t"e "ydration process o+ (C to +orm t"e calci&m silicate "ydrate 4C-S-H5 3el,

In 1;>olanss&c" as 6last +&rnace sla3mi3"t 6e activated &sin3al%aline li8&ids to +orm a 6inder and "ence totallyreplace t"e &se o+ (C inconcrete, Hence in t"is paper an e++ort is made toidenti+y and st&dy t"ee++ect o+ salient parameters t"at a++ectst"e properties o+ low-calci&m +ly as"-6ased3eo-polymer concrete andt"e properties o+ concreteat varied concentrationso+ al%ali sol&tions and

"ow t"e c"an3e intemperat&re a++ects t"estren3t" c"aracteristics,

35. G?(LYM

?$

Geo-polymer is a termcoverin3 a class o+ synt"etic al&mino-silicatematerials wit" potential&se in

a n&m6er o+ areas essentially as a replacement+or (ortland cement and +or advanced "i3"-tec"

composites ceramicapplications or as a +ormo+ cast stone, 0"e nameGeo-polymer was +irstapplied to t"esematerials 6y @osep" avidovits insimilar materials "ad 6een

+ormer Soviet 2nionsince t"e 1;/sori3inally &nder t"e namesoil cements, Howevert"is name never +o&nd

widespread &sa3e in t"e?n3lis" lan3&a3e as it is

more o+ten applied to t"edescription o+ soils w"ic"are consolidated wit" asmall amo&nt o+ (ortlandcement to en"ancestren3t" and sta6ility,Geo-polymer cements arean e7ample o+ t"e 6roader class 6inders w"ic" also inc

activated metall&r3icalsla3s and ot"er relatedmaterials

A+ %onstituents of (eo- polmer concrete

0"ere are two mainconstit&ents o+ 3eo- polymers namely t"e

so&rce materials and t"eal%aline li8&ids, 0"eso&rce materials +or 3eo- polymers 6ased onal&mina-silicate s"o&ld 6e ric" in silicon 4Si5

and al&mini&m 4Al5,0"ese co&ld 6e nat&ralminerals s&c" as%aolinite clays etc,Alternatively 6y- prod&ct materials s&c"

as +ly as" silica +&me

sla3 rice-"&s% as" redm&d etc, co&ld 6e &sedas so&rce materials, 0"ec"oice o+ t"e so&rcematerials +or ma%in3

3eo-polymers dependson +actors s&c" asavaila6ility cost type o+ application and speci+icdemand o+ t"e end &sers,

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+ .l Ash

Accordin3 to t"e American Concrete Instit&te 4ACI5Committee 11$ +ly as" is de+ined as Dt"e +inely dividedresid&e t"at res&lts +rom t"e com6&stion o+ 3ro&nd or powdered coal and t"at is transported 6y +l&e 3asses +romt"e com6&stion >one to t"e particle removal system‟4ACI Committee #'# #*5, Fly as" is removed +rom t"ecom6&stion 3ases 6y t"e d&st collection system eit"er mec"anically or 6y &sin3 electrostatic precipitators 6e+ore t"ey are disc"ar3ed to t"e atmosp"ere, Fly as" particles are typically sp"erical +iner t"an (ortlandcement and lime ran3in3 in diameter +rom less t"an 1Em to no more t"an 1/ Em,

0"e c"emical composition is mainly composed o+ t"eo7ides o+ silicon 4Si#5 al&mini&m 4Al#'5 iron4Fe#'5 and calci&m 4Ca5 w"ereas ma3nesi&m

potassi&m sodi&m titani&m and s&lp"&r are also presentin a lesser amo&nt,

3igure * 4ngraded fly%ash

3igure " 5raded fly%ash

0"e c"aracteristics o+ +ly as" t"at 3enerallyconsidered are loss oni3nition 4LI5 +inenessand &ni+ormity, LI is ameas&rement o+ &n-6&rntcar6on remainin3 in t"eas", Fineness o+ +ly as"mostly depends on t"eoperatin3 conditions o+ coal cr&s"ers and t"e3rindin3 process o+ t"ecoal itsel+, Finer 3radation 3enerally

res&lts in a more reactiveas" and contains lesscar6on,

%+ /se of .l Ash in%oncrete

Fly as" plays t"e roleo+ an arti+icial po>>olanw"ere its silicon dio7idecontent reacts wit" t"ecalci&m "ydro7ide +romt"e cement "ydration process to +orm t"ecalci&m silicate "ydrate4C- S-H5 3el, 0"esp"erical s"ape o+ +lyas" o+ten "elps toimprove t"e wor%a6ilityo+ t"e +res" concretew"ile its small particlesi>e also plays as +iller o+ voids in t"e concrete"ence to prod&ce denseand d&ra6le concrete,

An importantac"ievement in t"e &seo+ +ly as" in concrete is

t"e development o+ "i3"vol&me +ly as" 4H!FA5concrete t"ats&ccess+&lly replaces t"e&se o+ (C in concrete&p to and yet possesses e7cellentmec"anical propertieswit" en"anced d&ra6ility per+ormance,

D+ Al0aline i2uids

0"e most commonal%aline li8&id &sed in

3eo-polymerisation is acom6ination o+ sodi&m"ydro7ide 4)aH5 or

potassi&m "ydro7ide4KH5 and sodi&msilicate or potassi&msilicate 4avidovits1;;;9 (alomo et al, 1;;;9Bar6osa et al, #9 &and van eventer #9Swanepoel and Strydom##9 & and vaneventer ##5, 0"e &seo+ a sin3le al%alineactivator "as 6eenreported 4(alomo et al,1;;;9 0ei7eira- (into etal, ##5

(alomo et al 41;;;5concl&ded t"at t"e typeo+ al%aline li8&id playsan important role in t"e polymerisation process,$eactions occ&r at a "i3"rate w"en t"e al%alineli8&id contains sol&6lesilicate eit"er sodi&m or potassi&m silicatecompared to t"e &se o+ only al%aline "ydro7ides,

& and van eventer 4#5 con+irmed t"at t"eaddition o+ sodi&msilicate sol&tion to t"esodi&m "ydro7idesol&tion as t"e al%alineli8&id en"anced t"ereaction 6etween t"eso&rce material and t"esol&tion, F&rt"ermorea+ter a st&dy o+ t"e 3eo- polymerisation o+ si7teennat&ral Al-Si minerals

t"ey +o&nd t"at 3enerallyt"e )aH sol&tionca&sed a "i3"er e7tent o+ dissol&tion o+ mineralst"an t"e KH sol&tion,

'+ Super *lasticisers

In order to improvet"e wor%a6ility o+ +res"concrete "i3"-ran3ewater-red&cin3nap"t"alene 6ased s&per plasticiser was added tot"e mi7t&re, 0"e dosa3e

o+ s&per plastici>er also"as an e++ect on t"ecompressive stren3t" o+ t"e concrete,

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0"e speci+ic s&per plastici>er &sed in t"e mi7t&remade +or t"e pro.ect is Si%ament-/=1,As a s&per plastici>er it s&6stantially improved t"e wor%a6ilitywit"o&t increasin3 t"e amo&nt o+ water and "encered&cin3 t"e ris% o+ se3re3ation, It res&lts in normal seteven w"en overdosed, It 3ives a 3ood s&r+ace +inis" andas it is c"loride +ree it doesn t attac% rein+orcement or ‟ pre-stressed ca6les i+ any, Apart +rom t"is vario&s ot"er s&per plasticisers w"ic" can 6e &sed are cate3ori>ed as

1S&per (lasticiser A 4)ap"t"aleneFormalde"yde Condensate5

2S&per (lasticiser B 4S&lp"onated MelamineFormalde"yde Condensate5

3S&per (lastici>er C 4A8&eo&s e(olicar6o7ilato5

4S&per (lastici>er 4A8&eo&s Sol&tion o+ Li3no S&lp"onate5

0"e main c"emical 6ase is Modi+ied )ap"t"aleneFormalde"yde and t"e dosa3e varies +rom ,-# o+ t"ewei3"t o+ +ly as",

.+ *olmerisation *rocess

Geo-polymers are

mem6ers o+ t"e +amily o+

inor3anic polymers, 0"e

c"emical composition o+

t"e 3eopolymer material

is similar to nat&ral

>eolitic materials 6&t t"e

microstr&ct&re is

amorp"o&s, 0"e

polymeri>ation process

involves a s&6stantially

+ast c"emical reaction&nder al%aline condition

on Si- Al minerals w"ic"

res&lts in a t"ree-

dimensional polymeric

c"ain and rin3 str&ct&re

consistin3 o+ Si-- Al-

6onds

M n -4Si#5 > 6

Al# n .

wH #

:"ereJ M t"eal%aline element orcation s&c" as potassi&msodi&m or calci&m9

0"e sym6ol 6 indicates t"e presence o+ a 6ond n is t"ede3ree o+ poly-condensationor polymerisation9> is 1 #' or"i3"er &p to '#,

0"e sc"ematic+ormation o+ 3eopolymermaterial can 6e s"own asdescri6ed 6y

n4Si#/Al##5#nSi#*nH#

)aH or KH

)a

K

n4H5'-Si--Al---Si-4H5' 4Si-

Almaterials5

4H5

n4H5'-Si--

Al---Si-4H5'

)aH or KH

4)aK5-4-

Si--Al---Si--5 *nH# 4H5#

0"e c"emical reaction maycomprise t"e +ollowin3 steps

1issol&tion o+ Siand Al atoms +romt"e so&rce materialt"ro&3" t"e actiono+ "ydro7ide ions,

20ransportation or orientation or condensation o+ prec&rsor ions

into monomers,3Settin3 or poly-

condensationpolymerisation o+ monomers into polymericstr&ct&res,

However t"ese t"ree stepscan overlap wit" eac" ot"er and occ&r almostsim&ltaneo&sly t"&s ma%in3it di++ic&lt to isolate ande7amine eac" o+ t"emseparately 4(alomo et al,1;;;5,

0"e last term in ?8&ationreveals t"at water is releasedd&rin3 t"e c"emical reaction

t"at occ&rsin t"e+ormationo+ 3eo- polymers,0"is watere7pelled+rom t"e3eo- polymer matri7d&rin3 t"ec&rin3 and+&rt"er

dryin3 periodsleaves 6e"inddiscontin&o&s )ano- pores int"e matri7w"ic" provide 6ene+its tot"e per+ormance o+ 3eo-

polymers,0"e water in a 3eo-

polymer mi7t&ret"ere+ore plays norole in t"ec"emicalreactiont"at ta%es place9 itmerely providest"ewor%a6ility to t"e

mi7t&red&rin3"andlin3,0"is is incontrast tot"ec"emicalreaction o+ water in a(ortlandcementmi7t&red&rin3 t"e"ydration

process,

G+ %hemicalcomposition of the (eo-

polmers

i++erences d&e tovario&s conditions o+ t"eal%aline activation may 6e +o&nd on t"e F0I$spectra,

3igure 7eginning of thegeo%0olymers 0hasedevelo0

ment on

the surfaceof the flyash0article

0"e 6andcorrespondin3 to Si-and Al-vi6rationscan 6eo6servedin t"eori3inal +lyas" at1=-

1;

cm-1

6&tt"is 6andisdisplacedtowardslowerval&es int"e 3eo- polymers,

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0"e s"i+t is interpreted as a conse8&ence o+ t"e Al penetration into t"e ori3inal str&ct&re o+ t"e Si--Ss%eleton 4an analo3o&s p"enomenon was o6served in>eolites5, 0"e more prono&nced t"e s"i+t t"e 3reater t"ee7tent o+ t"e Al penetration +rom t"e 3lassy parts o+ t"e

+ly as" into t"e Si**-

s%eleton,

0"e 3eo-polymeri>ation process 4al%aline activation o+ +ly as"es in t"e a8&eo&s environment at pHN1#5

accompanied 6y t"e "ardenin3 o+ t"e material is di++erent+rom t"e "ydration processes o+ inor3anic 6inders 4e,3,(ortland cement5, 0"is process o6vio&sly ta%es place predominantly Ovia sol&tionP w"en +irst t"e +ly as"

particles are dissolved and a new 3eo-polymers str&ct&reis t"en +ormed startin3 +rom t"e sol&tion 4Fi3 '5,

In addition to t"e preparation conditions also t"e presence o+ Ca atoms enterin3 t"e Si- -Al- s%eletonand compensatin3 t"e c"ar3e on Al atoms plays animportant role,

3igure & 8etailed character of the geo%0olymers (the 0aste w 9$." fracture surface after "+ days/

0"ese c"ar3es are &s&ally compensated 6y )a ions,

)evert"eless Ca#

ions may pro6a6ly interconnectindivid&al Si--Al- c"ains t"&s 3ivin3 rise to astron3er str&ct&re c"aracteri>ed 6y "i3"er stren3t" val&esres&ltin3 +rom t"e al%aline activation o+ +ly as"es in presence o+ Ca-containin3 materials,

:ater is present in t"e 3eo-polymers str&ct&re as t"isis revealed 6y t"e G0A c&rves, :ater o6vio&sly occ&rs int"e +orm o+ O+ree waterP 6&t water molec&les also e7ist

inside t"e str&ct&re9 +&rt"ermore H- 3ro&ps are also

present,

A prevailin3 part o+water 3ets lost d&rin3t"e "eatin3

at a temperat&re o+ 1/-

#o

C, )o crystalline"ydrates co&ld 6edetected in t"e 3eo- polymers microstr&ct&re,

0"ere+ore t"e 3eo- polymer can 6ec"aracteri>ed as t"ree-dimensional inor3anic polymer wit" a s&mmary+orm&laJ

Mn -4Si-5> QAl-n ,

w4H#5+

61. ?(?$IM? )0AL

?2C0I )S

1. Mi4ture *roportions

0"e mi7t&re proportion o+ concrete contains

coarsea33re3ate +ine a33re3ate+ly as" Sodi&m silicatesol&tion and )aHsol&tion, 0"ree di++erentmi7t&res wit" =M 1M1#M and 1*M were prepared andcompressive stren3t"s o+ t"ese sample c&6es weremeas&red,

0"e sodi&m "ydro7ide4)aH5 solids weredissolved in water to

ma%e t"e sol&tion, 0"emass o+ )aH solids in asol&tion varieddependin3 on t"econcentration o+ t"esol&tion e7pressed interms o+ molar M,

For instance )aHsol&tion wit" a

concentration o+ =Mconsisted o+ =7* '#3rams o+ )aH solids4in +la%e or pellet +orm5 per litre o+ t"e sol&tionw"ere * is t"emolec&lar wei3"t o+ )aH, Similarly t"emass o+ )aH solids per %3 o+ t"e sol&tion +or 1*M concentration wasmeas&red as ** 3rams,

0"e sodi&m silicatesol&tion and t"e sodi&m"ydro7ide sol&tion weremi7ed to3et"er at leastone day prior to &se to prepare t"e al%alineli8&id, n t"e day o+ castin3 o+ t"e specimenst"e al%aline li8&id wasmi7ed to3et"er wit" t"es&per plastici>er and t"ee7tra water 4i+ any5 to prepare t"e li8&idcomponent o+ t"emi7t&re,

3igure # chematic

diagrams for mi2ing

0rocess

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Table *

;i2ture 0ro0ortions

A33re3ates 4%35Fly-as"

:ater Stren3t"

Mi7t&re )o, content#mm 1mm *,


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Sodium Hydroxide(Kg)

c o m p r e s s i v e

s t r e

n g t h

40

30

N / m

m 2

20

10 Sodium0

NaO

H

%+ 'ffect of Molarit of Al0aline Solutions

Mi7t&re Concentration $atio o+ Compressive

o+ )aH Sodi&m stren3t" at <t"

sol&tion Silicate day in Mpa4In molars5 to 4C&red at =

)aHC5

sol&tion

1 1 M #,/ 1,/

# 1# M #,/ #,

' 1* M #,/ #,<

* 1 M #,/ #/,#=

c o m p r e s s i v e s t r e n g t h

3530

N / m m 2

25

2015

10 Strength

5

0

1

0 12 14 16

M M M MMolarity

D+ %urin( Temperature

Hi3"er c&rin3temperat&re res&lted inlar3er compressivestren3t" alt"o&3" anincrease in t"e c&rin3temperat&re 6eyond =de3rees Centi3rade didnot increase t"ecompressive stren3t"s&6stantially, 0"reedi++erent c&rin3temperat&res were &sedi,e, #/ = and 1de3rees Centi3rade,C&rin3 was per+ormed inan oven +or #* "o&rs,0"e res&lts s"own in0a6le con+irm t"at "i3"er c&rin3 temperat&reres&lted in "i3"er compressive stren3t",

,uring

;i2ture Tem0erature in),

1 #/

#

' =

'+ Addition of Super plastici:er

In +res" state t"e 3eo- polymer concrete "as asti++ consistency,Alt"o&3" ade8&atecompaction was

ac"ieva6le animprovement in t"ewor%a6ility wasconsidered as desira6le,As t"e concentration o+ S&per plastici>er increases t"e amo&nt o+ water re8&ired decreases,

Series o+ tests per+ormed to st&dy t"ee++ect o+ s&per plastici>er on +ly-as" concreteindicated t"at s&per plastici>er improved t"e

wor%a6ility o+ t"e +res"concrete 6&t "ad verylittle e++ect on t"e

compressive stren3t" &pto # o+ t"is admi7t&reto t"e amo&nt o+ +ly as" 6y mass,

.+ ;ater %ontent of Mi4ture

In ordinary (ortlandcement 4(C5 concretewater in t"e mi7t&rec"emically reacts wit"t"e cement to prod&ce a paste t"at 6inds t"ea33re3ates, In contrast

t"e water in a low-calci&m +ly as"-6ased3eo-polymer concretemi7t&re does not ca&se ac"emical reaction, In+act t"e c"emicalreaction t"at occ&rs in3eo-polymers prod&ceswater t"at is event&allye7pelled +rom t"e 6inder,

G+ Densit

0"e density o+ concrete primarilydepends on t"e &nit masso+ a33re3ates &sed in t"emi7t&re, Beca&se t"etype o+ a33re3ates in allt"e mi7t&res did notvary t"e density o+ t"elow-calci&m +ly as"- 6ased 3eo-polymer concrete varied onlymar3inally 6etween

#'' to #*' %3m',

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22. $ A0? A )ALYSIS

1.%ement %oncrete 7Grade M$"9

ate Amount

(in ?g/ (>s./

Cement * /,# #=

Fine* 1 *#

A33re3ate

Coarse1#= 1# 1=

A33re3ate

S&per ,** er

Total ++

Note All the rates are as per the standard rates in the pre&alent Indian mar0et durin( the ear $"1$+

+ Geo-polmer %oncrete 7Grade M$"9

ate Amount

(in ?g/ (>s./

Fine* 1 *#

A33re3ate

Coarse1#= 1# 1=A33re3ate

S&per ,** er

)aH 1;,


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economical, However in t"e 6roader pict&reconsiderin3 car6on credit waste disposal andlimited availa6ility o+ non-renewa6le reso&rces

3eo-polymer concrete is s&re to play ma.or role in

constr&ctionind&stry,

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$?F?$?)C?S

[1] avidovits @, GeopolymersJ Inor3anic (olymeric )ewMaterials @o&rnal o+ 0"ermal Analysis 'anianpo&r, OFly As" inConcreteP, ttawa ntario Canada CA)M?0 1;;*,

[8] Mal"otra !, M, OMa%in3 concrete 3reener wit" +ly-as"P ACIconcrete international #14/5J /- 1;;;,

[9] Mal"otra !, M OHi3" per+ormance "i3" vol&me+ly-as" concreteP ACIconcrete international#*4

Documents

Fly Ash Based Gpc