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  • 8/12/2019 ISC 2013 Full Paper

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    3rdInternational Science Congress

    8th- 9thDecember 2013 at Karunya Uniersity

    Calcite crystals precipitation byBacillus subtilis JC3

    as a mechanism for strength improvement of cement mortar

    M V Seshagiri Rao1, V Srinivasa Reddy2, Ch Sasikala3, Ram!"1Professor, Dept. of Civil Engineering, JNTUH College of Engineering, Hyderabad-8, !P, "ND"!.

    #

    !sso$iate Professor, Dept. of Civil Engineering, %&"ET, Hyderabad-'(, !P, "ND"!.) Centre for Environ*ent, JNTU Hyderabad-8, !P, "ND"!.+ .Te$ "nfrastr/$t/ral Engineering0, JNTUH College of Engineering, Hyderabad-8, !P, "ND"!.

    #S$RC$

    Pre$ipitation of Cal$ite $rystals by *i$roorganis* !acillus subtilis JC) as been investigated for its ability to

    i*prove te strengt and d/rability properties of $e*ent *ortar d/e to te grot of filler *aterial itin te pores

    of $e*ent-sand *atri2 en introd/$ed into te ig pH environ*ent of $e*ent-sand *atri2. Te ba$teri/*

    !acillus subtilis tro/g nitrogen $y$le pre$ipitates $al$i/* $arbonate $rystals *etaboli$ally by o2idative

    dea*ination of a*ino a$ids a**onifi$ation0. "t as observed at $ell $on$entration *ore tan 1( $ell3*l of ater,strengts are red/$ed d/e to disr/ption of $e*ent sand *atri2 integrity. Ter*ogravi*etri$ analysis soed tat

    ba$teria ere able to pre$ipitate CaC4) $rystals inside te pores of $e*ent-sand *atri2. 5iability of ba$teria istested in ardened $e*ent *ortar sa*ples after a $ertain period of ti*e. 6$anning Ele$tron i$ros$opi$ and 7-ray

    diffra$tion analyses ill/strated bot te $rystal grot and presen$e of te $al$ite $rystals.

    %ey&ords'!acillus subtilisJC), ba$terial $e*ent *ortar, bio-*ineraliation, 6E, 7&D, T%!.

    ()$R*+C$(*)

    9or $ra$: repair, a variety of te$ni;/es are available b/t traditional repair syste*s i.e., synteti$ poly*ers ave a

    n/*ber of disadvantageo/s aspe$ts s/$ as different ter*al e2pansion $oeffi$ient tan $e*ent *ortar and also poseenviron*ental and ealt aards1. Terefore, ba$teriogeni$ $al$i/* $arbonate pre$ipitation as been proposed as

    an alternative and environ*ental friendly *etod to enan$e te perfor*an$e of $e*ent *ortar. 6everal of tese

    repairing syste*s are organi$ $oatings $onsisting of volatile organi$ $o*po/nds. Te air poll/ting effe$t of tese

    $o*po/nds d/ring *an/fa$t/ring and $oating as lead to te develop*ent of ne for*/lations s/$ as inorgani$

    $oating *aterials *ade /p of $al$i/*-sili$ate $o*po/nds, i$ e2ibit a $o*position si*ilar to $e*ent #. Te

    transport of aggressive gases and3or li;/ids into $e*ent *ortar depends on its per*eation $ara$teristi$s. !s te

    per*eation of $e*ent *ortar de$reases, its d/rability perfor*an$e, in ter*s of pysi$o$e*i$al degradation,

    in$reases). "n $e*ent *ortar, it is generally not te porosity b/t te pore str/$t/re tat is essential in establising teper*eability. "n addition to tat, *i$ro-$ra$:s in te *atri2 *ay $ontrib/te signifi$antly to te per*eability+.

    &e$ently, *i$robial *ineral pre$ipitation res/lting fro* *etaboli$ a$tivities of so*e spe$ifi$ *i$roorganis*s in

    $e*ent *ortar as be$o*e an i*portant area of resear$. 6everal ba$teria ave te ability to pre$ipitate $al$i/*

    $arbonate. Tese ba$teria $an be fo/nd in soil, sand, nat/ral *inerals et$. Co*pared to nat/ral $arbonation of

    $e*ent *ortar, bio-deposition is a relatively ;/i$: pro$ess. Nat/ral $arbonation o$$/rs fro* te dissol/tion of

    at*osperi$ C4#in te pore sol/tion and for*ation of CaC4) fro* C-6-H or portlandite. "n te bio-deposition

    treat*ent oever, $al$i/* ions are also provided by an e2ternally added $al$i/* so/r$e, ile te $arbonate ions

    res/lt fro* te *i$robiologi$al ydrolysis of a*ino a$idseast e2tra$t= ) g3lit. and beef e2tra$t as /sed for $/ltivation of *i$roorganis*s.!"subtilis$ell

    $an attra$t Ca ions Ca#?0, i$ rea$t it $arbonate ions C4)#- originating fro* peptone d/ring o2idativedea*ination of a*ino a$ids. 6i*/ltaneo/sly, a**onia ions NH+

    ? in$rease pH val/e in s/rro/nding *edi/* i$

    i*proves $al$ite pre$ipitation effi$ien$y. Pre$ipitation of $al$i/* $arbonate $rystals o$$/rs by eterogeneo/s

    n/$leation on te ba$terial $ell all on$e s/per-sat/ration is a$ieved. Te *i$robial pre$ipitation of CaC4 ) is

    deter*ined by several fa$tors in$l/ding= te $on$entration of dissolved inorgani$ $arbon, te pH, te $on$entration

    of $al$i/* ions and te presen$e of n/$leation sites@. Te first tree fa$tors are provided by te *etabolis* of teba$teria ile te $ell all of te ba$teria ill a$t as a n/$leation site8. Tis!"subtilisstrain as $osen be$a/se of

    its greatest potential for pre$ipitation of $al$i/* $arbonate, even /nder e2tre*e $onditions, as ell as its la$: of

    patogeni$ity and a very negative eta-potential.

    1

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    3rdInternational Science Congress

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    Ca#? ?!"subtilisCell A!"subtilisCell- Ca#?

    CH)CHNH#0C44H Peptone0 ? B4# --------- C#H# ? H#C4)? NH)H#C4) ---------- H

    ? ? HC4)-

    NH)? H#4 -------- NH+? ? 4H-

    !"subtilisCell- Ca#? ? C4)#- A!"subtilisCell- CaC4)

    Presen$e of $al$i/* $arbonate $rystals $overing fine aggregate grains as $onfir*ed by observations /nders$anning ele$tron *i$ros$ope 6E0. Te presen$e of $loride ions res/lted in ro*boedra $rystals, ile te

    presen$e of a$etate ions res/lted in speri$al $rystals'.R-S-RC S(.)((C)C-

    Te notion of self-ealing $e*ent *ortar tat $an repair itself ito/t /*an intervention see*s to be te st/ff of

    s$ien$e fi$tion till no b/t resear$ $ond/$ted at JNTU Hyderabad on ba$teria in$orporated $e*ent *ortar realies

    te potential of tis ne field of bio-inspired self repair innovation. &esear$ as indi$ated tat a $e*ent *ortari$ is lo in per*eation properties lasts longer ito/t e2ibiting any signs of distress and deterioration.

    etods $/rrently /sed for $ra$: re*ediation often /se synteti$ poly*ers i$ are e2pensive and aesteti$ally

    /npleasant parti$/larly in repairing istori$ *on/*ents. e$a/se of tese disadvantages of $onventional s/rfa$e

    treat*ents, attention as been dran to ba$terial $e*ent *ortar, an alternative te$ni;/e for te i*prove*ent of te

    d/rability of $e*ent *ortar. 6o, "f in so*e ay a reliable *etod $o/ld be developed tat repairs $ra$:s and

    enan$es $orrosion resistan$e in $e*ent *ortar a/to*ati$ally self ealing0, i$ $o/ld in$rease and ens/re

    d/rability and f/n$tionality of str/$t/res enor*o/sly res/lts in te $on$eption of a$terial Ce*ent *ortar F.

    -0-R(M-)$/ ()V-S$(.$(*)S

    Te folloing laboratory tests ere $ond/$ted in order to as$ertain te infl/en$e of $al$i/* $arbonate pre$ipitation

    on te pysi$o-*e$ani$al properties of $e*ent *ortar.

    Compressive Strength

    Tis investigation is $arried o/t pri*arily to /nderstand te effe$t of ba$terial $ell $on$entration on te rate and

    ;/antity of $al$i/* $arbonate pre$ipitation. ore ba$teria it s/ffi$ient n/trients ill pre$ipitate *ore $al$ite in

    te laboratory $onditions b/t in te $e*ent-sand environ*ent, ba$teria *ineral pre$ipitating ability depends on its

    $o*patibility it $e*ent-sand *atri2. a$teria in$orporated into $e*ent-sand *edi/* so/ld not affe$t te

    pysi$-$e*i$al properties of $e*ent-sand. 6o $ell $on$entration of ba$teria plays a :ey role in *a2i*iing te

    perfor*an$e of $e*entitio/s *aterials. 6o appropriate ba$terial $ell $on$entration for opti*ied $al$i/* $arbonatepre$ipitation $an be establised by deter*ining te $o*pressive strengts of vario/s $e*ent-*ortar spe$i*ens

    ind/$ed it different ba$terial $ell $on$entrations. Te sa*ple ose $o*pressive strengt is *a2i*/*

    deter*ines te opti*/* $ell $on$entration for ig a*o/nt of $rystalline $al$ite pre$ipitation. 6tandard Ce*ent-*ortar $/bes @(.

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    ore realisti$ $ra$:s ere obtained by applying at least

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    -lemental Composition by Chemical nalysis

    6a*ple $onsisting of ardened ba$teria treated and /ntreated $ontrol $e*ent *ortar bro:en pie$es gro/nded fine and

    as analyed $e*i$ally in order to deter*ine te ele*ental $o*position as son in Table +. "t as observed tat

    relative per$entage of Cal$i/* 42ide in$reased in $ase of ba$terial spe$i*ens as $o*pared to $ontrolled spe$i*ens

    i$ indi$ate te presen$e of $al$ite *ineral.

    #acteria Viability $est

    ! pie$e of ba$terial $e*ent *ortar of 18( days age is ino$/lated in n/trients brot and :ept in orbital sa:er for #+

    rs. !fter #+ in$/bation, a loop f/ll of $/lt/re is ta:en fro* te brot and strea:ed on agar plate. 4n$e $olonies are

    for*ed teir *orpologi$al $ara$teristi$s and *i$ros$opi$ observations *at$ it !acillus subtilis JC). Tis

    $onfir*s te presen$e of *i$roorganis*s in $e*ent *ortar. Poto $ontrast pi$t/res son in 9ig @ establis tat

    ba$teria are still viable even after 18( days in $e*ent *ortar.

    0reliminary Cost -val!ation

    Te $ost3benefit analysis of ba$terial $e*ent *ortar balan$es te in$reased $ost of te $e*ent *ortar against

    s/bstantial repair *aterial $osts, enan$ed d/rability and aesteti$ benefits. Te benefits are apparent at strengt and

    perfor*an$e of te finised prod/$t. 4nly e2pensive $o*ponent in te develop*ent of ba$terial $e*ent *ortar is

    n/trients. !s ba$teri/* !acillus subtilis JC) is developed in JNTU Dis$overy lab, so it s/pplied free of $ost for

    resear$ p/rpose oterise te $ost of bio-deposition treat*ent depends on te pri$e of te *i$roorganis*s and

    n/trients. "n te *ar:et ba$teria is available is lyopilied state. 6o $ost depends on te s/rfa$e treat*ent area or

    vol/*e of $e*ent *ortar /sed. N/trients /sed for tis st/dy are laboratory n/trients i$ are ;/ite e2pensive sooter ine2pensive n/trient so/r$es $an also be tried to red/$e te $o**er$ial prod/$tion $ost of ba$terial $e*ent

    *ortar. Hoever, any n/trients s/$ as ine2pensive, ig-protein-$ontaining ind/strial astes s/$ as $orn steepli;/or C6K0 or la$tose *oter li;/or KK0 effl/ent fro* star$ ind/stry $an also be /sed so tat overall pro$ess

    $ost red/$es dra*ati$ally. Tese ind/strial effl/ents i$ are potential environ*ental poll/tants and also available

    lo$ally it a pri$e of nearly &s 1(( per liter, i$ is very e$ono*i$ $o*pared it standard laboratory n/trient

    *edi/*. "n tis proLe$t, to prepare one liter of n/trients *i2ed ba$terial $/lt/re, it re;/ired 1) gra*s of n/trients

    brot poder. Te $ost of (( gra*s of H"ED"! ((# n/trient brot poder $osts abo/t #)(( r/pees so to

    prepare one liter of n/trients *i2ed ba$terial $/lt/re $osts &s

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    $able 3' Compressive strengths of cement mortar specimens &ith realistic cracks

    $ype of specimen Compressive strength at 2= days 4M0a5

    Control spe$i*en 1.

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    ig 3' S-M images of !ntreated and bacteria treated s!rfaces

    Cell Concentration >)il 4Control Specimen5 Cell Concentration > 1?37ml

    Cell Concentration > 1?"7ml Cell Concentration > 1?@7ml 4*ptim!m5

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    75

    80

    85

    90

    95

    100

    105

    0 100 200 300 400 500 600 700 800 900 1000

    $emperatureoC

    %eight

    without bacteria

    with bacteria

    CaCO3

    Disintegrates

    exulsion o!

    e"aorable water

    h#$ratation o! the

    h#$rate calciu%

    silicate

    $eco%osition o!

    Ca(O&'2

    $eco%osition o!

    h#$rate calciu%

    silicate

    0

    0(1

    0(2

    0(3

    0(4

    0 100 200 300 400 500 600 700 800 900 1000

    $emperatureoC

    Changein%eight(&/oC)

    without bacteria

    with bacteria

    ig A' $. Res!lts sho&ing &eight loss and Change in &eight loss per oC

    $able "' -lemental composition of cement mortar specimens treated &ith and &itho!t bacteria

    Constit/ent

    Control 6pe$i*en

    G by eigt of te sa*ple

    ta:en

    a$teria treated spe$i*en

    G by eigt of te sa*ple ta:en

    Koss on "gnition (.8) (.8'

    6ol/ble 6ili$a6i4#0 .(+ +.'@

    9erri$ 42ide 9e#4)0 1.(< 1.(#

    !l/*ina!l#4)0 1.# 1.('

    Cal$i/* 42ideCa40 1

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    angani$ 42iden#4)0 (.(+ (.(+

    Total Clorides (.((# (.((#

    6/lpide 6/lp/r (.(@ (.(@

    ig ;' 0hase contrast microscopic pict!res identify microorganisms and &hite calci!m carbonate crystals

    formation

    +(SCSS(*) * $-S$ R-S/$S

    !n al:alipili$ aerobi$ soil *i$roorganis*!acillus subtilis JC) is in$orporated at different $ell $on$entrations it

    te *i2ing ater. Different $ell $on$entrations ere derived fro* te ba$terial grot $/lt/re by serial dil/tion

    *etod. 9or $ell $on$entration of 1( $ells per *l of *i2ing ater te $o*pressive strengt of ba$teria in$orporated

    $e*ent *ortar spe$i*ens is *a2i*/* in$reased by 1

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    ater so tis is ta:en as opti*/* $ell $on$entration to be /sed for f/rter st/dy. "f te $ell $on$entration is *ore

    tan opti*/* ten te loss of strengt is observed d/e to disr/ption of $e*ent Msand *atri2. Te strengt

    i*prove*ent is d/e to grot of filler *aterial itin te pores of te $e*entMsand *atri2. Te *odifi$ation in

    pore sie distrib/tion and total pore vol/*e of $e*entMsand *ortar d/e to s/$ grot is also noted.

    6t/dies soed tat te si*/lated $ra$:ed $/be filled /p it standard sand *i2ed it ba$terial $/lt/re asregained te strengt to abo/t +

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    3rdInternational Science Congress

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    *i$robial $al$ite pre$ipitation. Higer strengt regain as obtained be$a/se of te ba$terial CaC4)pre$ipitation

    inside te si*/lated $ra$:s of $e*ent *ortar spe$i*ens.

    C%)*/-+.-M-)$

    !bove tests ere $ond/$ted at JNTU Hyderabad Civil Engineering Ce*ent *ortar Te$nology Kaboratory,iote$nology Kaboratory at JNTU Hyderabad Centre for Environ*ent and "ndian "nstit/te of Ce*i$al

    Te$nology Hyderabad.

    R--R-)C-S

    1. &a*a:risnan 6., Pan$alan &., ang 6.6, "*prove*ent of $e*ent *ortar d/rability by ba$terial

    *ineral pre$ipitationF,#roceedings o$ 11th International Con$erence on %racture, T/rin, "taly, #((1.

    #. &a*a$andran 6., &a*a:risnan 5, ang 6.6, &e*ediation of $e*ent *ortar /sing *i$ro-organis*sF,

    &CI 'aterials (ournal'8 #((10 )M'.). %os P, andal 6, Cattopadyay .D, Pal 6, Use of *i$roorganis* to i*prove te strengt of $e*ent

    *ortarF, Cement and Cement mortar )esearch) 1(0 #((0 1'8(M1'8).

    +. Di$: J, De indt , De %raef , 6aveyn H, 5an der eeren P, De elie N, 5erstraete , io-

    deposition of a $al$i/* $arbonate layer on degraded li*estone by a$ill/s spe$iesF, !iodegradation 51@

    +0 #((