Effect of short fibres on fracture behaviour of textile reinforced concrete

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1 Fratur Mhani Conrt and Conrt Strutur - High Prforman, Fibr Rinford Conrt, Spial Loading and Strutural Appliation- B. H. Oh, t al. (d) 2010 Kora Conrt Intitut, ISBN Efft hort fibr on fratur bhaviour txtil rinford onrt R. Barhum & V.Mhthrin Intitut Contrution Matrial, TU Drdn, Drdn, Grmany ABSTRACT: Txtil rinford onrt (TRC) xhibit vry favourabl tr-train bhaviour with high load-arrying apaity, ahivd only aftr rlativly high dformation aompanid by formation a onidrabl numbr fin rak. Thi artil addr th fft uing hort fibr (gla and arbon) on th fratur bhaviour thi matrial a additional rinformnt in TRC. A ri uniaxial, dformationontrolld tnil tt wr prformd. Diprd and intgral hort gla fibr a wll a diprd hort arbon fibr wr ud in th invtigation. On on hand, TRC plat with high dgr rinformnt, both parat and in ombination with a low dgr hort fibr wr ttd. On th othr hand, xprimnt on TRC plat with a rlativly low dgr txtil rinformnt, parat and in ombination with a high dgr hort fibr wr prformd. Vry pronound fft du to th diffrnt typ hort fibr on th tr-train bhaviour and raking TRC ould b obrvd. In partiular, a pronound inra in th firt-rak tr wa obrvd in all a whn hort fibr had bn addd. Still furthr, th influn diprd and intgral hort gla fibr on th our tr-train urv TRC wr ompard. Finally th obrvd phnomna wr diud and laifid a to thir undrlying au with th upport miroopi invtigation and viual inption on th pimn urfa. 1 INTRODUCTION Txtil rinford onrt (TRC) i a ompoit matrial oniting a finly graind mntbad matrix and high-prforman, ontinuou multifilamnt yarn mad alkali-ritant gla, arbon, or polymr. Th hif advantag TRC ar it high tnil trngth and pudo-dutil bhaviour, haratrid by larg dformation du to it tolran multipl raking. Thi intrting matrial with it xllnt mhanial proprti an b highly appropriat to many appliation both for nw trutur and for th trngthning or rpair old trutural lmnt mad rinford onrt or othr traditional matrial (Bramhubr 2006, Curbah & J 2009). Prviou invtigation howd that txtil rinford onrt ha a high tnil trngth, whih i typially rahd at rlativly larg dformation (J 2004). Suh larg dformation prior to matrial failur ar vry important with rgard to trutural afty a wll a th nrgy diipation in a impat loading. Howvr, that high trngth lvl an b only rahd at high dformation man that for th rvi tat, whr only mall dformation an b aptd, th dign loadbaring apaity TRC mut b lowr than it tnil trngth. Morovr, rlativly wid rak obrvd at high dformation ar undirabl. In rnt yar, vral tt ri hav bn prformd to invtigat th influn hort fibr on diffrnt proprti txtil rinford onrt (Butlr t al. 2006, Hinzn & Bramhubr 2007). Howvr, th mhanim th joint ation hort fibr and txtil rinformnt ar till not fully undrtood. In ordr to gain bttr inight into th pifi matrial bhaviour th fin-graind onrt with uh hybrid rinformnt, a nw invtigativ programm wa tartd at th TU Drdn. In thi tudy th fft uing diffrnt typ hort fibr on th fratur bhaviour in txtil rinford onrt ar invtigatd uing uniaxial tnion tt on thin, narrow plat mad TRC. Spial attntion i dirtd to th our th tr-train rlationhip and rak dvlopmnt. Furthrmor, viual inption pimn urfa and miroopi invtigation fratur urfa hav bn valuatd. On th bai th data, th mhanim th intration btwn ontinuou fibr and hort fibr in mnt-bad ompoit ar diud. 2 TYPICAL BEHAVIOUR OF TRC J (2004) howd that th bhaviour TRC undr tnil tr an b ubdividd into thr tat, a prntd hmatially in Figur 1. Th firt tat i th fr-rak tat, I. In thi tat,

2 TRC how linar-lati bhaviour until th tr inra lad to th formation th firt rak. Th ond tat IIa rprnt th tat rakformation, whr mor and mor rlativly fin rak form du to th inra in th tnil tr. Th rak-widning tat, IIb, i th lat tat in th tr-train rlation. In thi tat no or only a fw nw rak appar, but th xiting rak grow and bom widr until th ultimat tr i rahd and th matrial fail. Figur 1. Shmati rprntation a typial tr-train urv for TRC with indiation raking tat. 3 MATERIALS, TEST METHOD, TEST PARAMETERS 3.1 Matrial ompoition In prviou invtigation it wa found that matri with lag furna mnt (CEM III) and th addition pozzolan how favourabl proprti rgarding durability th gla fibr a wll a th bond btwn fibr and matrix (Butlr t al. 2005). On th fin-graind, mnt-bad onrt wa hon for thi invtigation. Th bindr wa ompod mnt, fly ah and miro ilia. Two mixtur, ah with diffring watr-tobindr ratio (0.3 and 0.45, rptivly), wr alibratd. Fin and with a maximum grain iz 1mm wa ud a aggrgat. Tabl 1 t out th matri ompoition. Finally, a uprplatiizr with a bai naphthaln-ulphonat wa addd in ordr to ahiv uffiint flowability. Th avrag lump flow valu obtaind with a mall on wa 200 mm. Coatd, biaxial fabri mad alkali-ritant gla (AR-gla) wa ud a txtil rinformnt. Two diffrnt dgr rinformnt wr ahivd by varying th numbr txtil layr. Th dgr rinformnt wa alulatd for on layr fabri in volum a 66.33mm 2 /m. Figur 2 how th typ txtil ud in thi invtigation. Th finn J = D ( h, th T ) wft h and warp thrad a wll a th paing btwn th yarn ar givn in Tabl 2. Th finn Th proportionality i givn in tx, fiint whih i D(h,T) qual to th wight moitur on prmability kilomtr and it yarn i a in nonlina gram. th rlativ humidity h and tmpratur & Najjar 1972). Th moitur ma balan Tabl 1. Matrix ompoition that th variation [kg/m³]. in tim th watr ma Watr-to-bindr ratio volum onrt (watr ontnt w) b q CEM III B 32.5 NW-HS-NA divrgn th moitur flux J Fly ah Miro ilia upnion * Fin and 0/1 w = J Watr t Suprplatiizr 11 2 * olid:watr = 50:50 Th watr ontnt w an b xprd a th vaporabl watr w (apillary wa Tabl 2. Txtil ud vapor, a rinformnt. and adorbd watr) and th non- NWM p2 (hmially (30%) bound) watr w n (Mil Warp Pantazopoulo Wft & Mill 1995). It i ra Finn Spaing Finn Spaing aum that th vaporabl watr i a fu [tx] [mm] [tx] [mm] 2* rlativ 2*640 humidity, 7.2 h, dgr hydration dgr ilia fum ration, α, i.. w =w Tabl 3. Typ fibr = ud ag-dpndnt and proprti. orption/dorption (Norling Mjonll 1997). Undr thi aum Diamtity Strngth Modulu Dn- Tnil Young Matrial obtain by ubtituting Equation 1 into Equati Typ [µm] [g/m 3 ] [MPa] [MPa] Diprgla + ( D h) = α& + α& + w AR ,000 Intgral ARgla ,000 Diprd Carbon whr ,000 / i th lop th orption/ iothrm (alo alld moitur apa govrning quation (Equation 3) mut b by appropriat boundary and initial onditi Th rlation btwn th amount watr and rlativ humidity i alld iothrm if maurd with inraing humidity and dorption iothrm in th a. Nglting thir diffrn (Xi t al. th following, orption iothrm will b rfrn to both orption and dorption By th way, if th hytri th iothrm would b takn into aount, two rlation, vaporabl watr v rlativ humi b ud aording to th ign th varia Figur 2. Biaxial txtil rlativity rinformnt humidity. mad Th AR-Gla. hap th iothrm for HPC i inflund by many p Diprd and pially intgral tho AR-gla that influn hort fibr xtnt and (SGF) a wll hmial a diprd ration hort and, arbon in fibr turn, dtrm (SCF) wr hon trutur for tting and por th iz TRC ditribution in ombi-(watrnation with txtil ratio, layr. mnt Whr hmial diprd ompoition, hort SF fibr ar dipribl uring in tim watr and and mthod, thy tmpratur, ditribut mix and prad in mixtur t.). In to thouand th litratur ingl variou monilamnt, th intgral found to hort drib fibr rmain th orption tuk to- iothrm formulatio gthr and tay onrt in trand (Xi in th t al. mixtur. 1994). All Howvr, typ in th fibr had a lngth papr th 6 mm. mi-mpirial Tabl 3 giv xprion othr pro proprti th Norling hort fibr. Mjornll (1997) i adoptd b Proding FraMCoS-7, May 23-28, 2010

3 3.2 J = D ( Prparation h, T ) h th pimn and tt tup (1) Rtangular plat 500mm long and 100mm wid wr Th ut proportionality out biggr fiint plat 525mm D(h,T) long i alld and 425mm moitur wid, prmability whih wr and produd it i a nonlinar uing a funtion lamination th rlativ thniqu. humidity Th laminating h and tmpratur pro T tartd (Bažant with & Najjar th prading 1972). Th moitur a thin onrt ma balan layr on rquir th bottom that th variation th mould. in tim Th firt th ht watr ma txtil pr rinformnt volum wa onrt laid (watr upon thi ontnt frh w) onrt b qual layr to th unit and divrgn thn, gntly, th partially moitur prd flux J in and moothd. Th omplt imbdding firt txtil layr took pla during th inrtion th ond onrt = J (2) layr; t th thikn th onrt layr dpndd on th dird thikn th plat and th Th dird watr numbr ontnt w txtil an b layr. xprd Subquntly, a th um th th prodution vaporabl tp watr wr w rpatd (apillary until watr, all rinforing vapor, and layr adorbd wr plad watr) and th inorporatd non-vaporabl into watr fin-graind (hmially onrt. bound) Th watr thikn w n (Mill th plat 1966, wa Pantazopoulo 12mm. & Mill 1995). It i raonabl to aum Th plat that th wr vaporabl dmouldd watr a onrt i a funtion ag two rlativ day humidity, and thn tord h, dgr in watr hydration, until an ag α, and 7 day. dgr Subquntly, ilia fum th ration, plat wr α, i.. tord w =win (h,α a limat-ontrolld = ag-dpndnt room orption/dorption at 20 C and 65%RH until iothrm an,α ) ag (Norling 28 Mjonll day. 1997). Undr thi aumption and by Th ubtituting uniaxial tnil Equation tt 1 on into th Equation narrow TRC 2 on plat obtain wr prformd with a dformation rat 0.5mm/min. Th loading wa inrad ontinuouly until failur ourrd. Th for wa tranfrrd to + th ( plat D h) via = non-rotatabl α& + α& tl + w& n plat (3) glud to th TRC plat. Dformation wa maurd by two linar variabl diffrntial tranformr whr (LVDT). / Figur i th 3 lop how th tt orption/dorption tup. iothrm (alo alld moitur apaity). Th govrning quation (Equation 3) mut b ompltd by appropriat boundary and initial ondition. Th rlation btwn th amount vaporabl watr and rlativ humidity i alld adorption iothrm if maurd with inraing rlativity humidity and dorption iothrm in th oppoit a. Nglting thir diffrn (Xi t al. 1994), in th following, orption iothrm will b ud with rfrn to both orption and dorption ondition. By th way, if th hytri th moitur iothrm would b takn into aount, two diffrnt rlation, vaporabl watr v rlativ humidity, mut b ud aording to th ign th variation th rlativity humidity. Th hap th orption iothrm for HPC i inflund by many paramtr, pially tho that influn xtnt and rat th Figur hmial 3. Shmati ration viw and, th in tt turn, tup (lft) dtrmin and a TRC por plat trutur during and a tnil por tt iz (right). ditribution (watr-to-mnt ratio, mnt hmial ompoition, SF ontnt, uring In ordr tim to and invtigat mthod, tmpratur, th influn mix additiv, th ltd t.). In typ th litratur hort fibr variou on th formulation fratur bhaviour found to txtil drib rinford th orption onrt, iothrm ombination normal an b paramtr onrt (Xi wr t al. ttd 1994). a Howvr, givn in Tabl in th 4. prnt For ah papr paramtr th mi-mpirial ombination, xprion at lat thr propod pi-by Norling Mjornll (1997) i adoptd bau it xpliitly mn with aount both typ for th fin-graind volution onrt hydration (f. ration Tabl 1) and wr SF produd ontnt. and Thi ttd. orption iothrm rad Tabl 4. Paramtr ombination. Txtil Short fibr 0.0 % 0.5 vol.-% 1.0 vol.-% 1 w ( h, α, α ) = G ( αgla, α ) 1Carbon Gla Gla + 1 (dipr) (dipr) 10( g α (dipr) α ) h (intgral) 2 layr X 1 X X (4) 4 layr X X X 10( g α α ) h K ( α, α ) RESULTS AND DISCUSSION whr th firt trm (gl iothrm) rprnt th In th following, th tr-train urv obtaind phyially bound (adorbd) watr and th ond from th uniaxial tnil tt ar prntd and trm valuatd. (apillary Th iothrm) intrprtation rprnt th rult th apillary i upportd watr. Thi by xprion viual inption i valid only th for ttd low ontnt pimn SF. Th urfa fiint and to G om 1 rprnt xtnt by th th amount rult watr miroopi pr unit invtigation. volum hld in th gl por at 100% rlativ humidity, and it an b xprd (Norling Mjornll 1997) a 4.1 Gnral fft hort fibr GInflun ( α, α ) = on k firt-rak α + k αtr (5) 1 vg vg An obviou inra in firt-rak tr wa larly obrvd in all xprimnt with th addition k vg hort and kfibr vg ar whn matrial ompard paramtr. to th From rult th whr maximum obtaind for amount th TRC watr without pr hort unit volum fibr. Thi that an fft all wa por mot (both pronound apillary por in th and tt gl with por), a rla- on fill an tivly alulat low dgr K 1 a on txtil obtain rinformnt (two txtil layr only) whn a rlativly high amount hort fibr wa addd. g α 1 w 0.188α α G K ( α, α ) = 1 g α α 1 1 Not that, at arly ag, in th hmial ration aoiatd with mnt hydration and SF ration ar xothrmi, th tmpratur fild i not uniform for Figur non-adiabati 4. Efft th ytm addition vn diprd if th hort nvironmntal gla fibr tmpratur on th mhanial i ontant. bhaviour Hat TRC plat ondution in tnion. an b dribd in onrt, at lat for tmpratur not xding Figur 100 C 4 how (Bažant th orrponding & Kaplan rult 1996), obtaind for law, TRC whih with rad and without th addition by Fourir 1% by volum diprd hort gla fibr. Th qwatr-bindr = λ T ratio th matrix wa 0.3. A an b (7) n in Figur 4 th firt-rak tr valu wa doubld du to th addition hort fibr. Thi whr q i th hat flux, improvmnt in matrial rpon T i th abolut an b aribd tmpratur, to thr probabl and λ raon: i th hat ondutivity; in thi α (6) Th matrial paramtr k vg and k vg and g 1 an b alibratd by fitting xprimntal data rlvant to fr (vaporabl) watr ontnt in onrt at variou ag (Di Luzio & Cuati 2009b). 2.2 Tmpratur volution Proding FraMCoS-7, May 23-28, 2010

4 1) Th bridging miro-rak by fin, wll ditributd hort fibr mitigat rak growth and onquntly th formation th firt marorak. Thu a highr tr i ndd to indu maro-raking. 2) Th addition hort fibr lad to a dra in dformation th matrix du to hrinkag (Barhum 2007) and thrfor rdu intrnal damag to th fin-graind onrt thrfrom. Furthrmor, hort fibr bridg miro-rak whih dvlop du to hrinkag (f. alo raon 1). 3) Du to th addition hort fibr th ovrall rinformnt dgr inra. Sin th trngth and tiffn AR-gla fibr i onidrably highr than th orrponding matrial paramtr th matrix, th trngth th rak-fr ompoit matrial (i.. th firt-rak tr) mut inra with inraing dgr fibr rinformnt. Efft on th formation multipl rak and th hap th tr-train urv Aftr th firt rak appar, th formation multipl rak bgin, (f. Fig. 1), whih i on th ky fatur TRC, in it tolrat high dformation, and thu ontribut favourably to th dutil bhaviour th ompoit. Dtail B in Figur 4 larly dmontrat th fft hort fibr addition at thi tag: Th train rgion whr multipl rak form xpand by mor than doubl du to th prn hort fibr. Thi xpanion an b trad bak to a highr numbr rak, a wa obrvd by th viual inption th pimn urfa. Figur 5 how that th urfa th TRC pimn ontaining hort fibr ha mor and finr rak in omparion to th TRCpimn without th addition hort fibr. Thr poibl mhanim rponibl for uh bhaviour an b namd at thi tag invtigation: 1) Highr tr lvl in th tt on th pimn with th addition hort fibr lad vn prior to th dvlopmnt th firt maro-rak to formation a gratr numbr miro-rak ovr th ntir pimn volum or lngth, rptivly. Bginning with th firt-rak tr th maro-rak dvlop from th miro-rak. A gratr numbr finly ditributd miro-rak fr mor nuli for maro-rak formation, lading to mor pronound multipl raking. 2) Th formation a maro-rak rult in a dra matrix tr in th viinity th rak. Th nxt rak may not form at a ditan blow a thrhold valu dpnding on th kind th rinformnt ud. Adding hort fibr au additional tr tranfr ovr th maro-rak, whih rult in a l pronound rlaxation th matrix in thir viinity. A nw rak an form at a mallr ditan from an xiting rak, thu mor pronound multipl raking an b obrvd. J = ) D ( h, T h Th proportionality fiint D(h,T) moitur prmability and it i a nonlina th rlativ humidity h and tmpratur & Najjar 1972). Th moitur ma balan that th variation in tim th watr ma volum onrt (watr ontnt w) b q divrgn th moitur flux J t w = J Th watr ontnt w an b xprd a th vaporabl watr w (apillary wa vapor, and adorbd watr) and th non- Figur 5. Crak pattrn TRC pimn rinford by two layr txtil: without (hmially hort fibr bound) (lft) and watr with 1.0% w n (Mil hort gla fibr (right) Pantazopoulo ttd in uniaxial & Mill tnion 1995). mod. It i ra aum that th vaporabl watr i a fu 3) Miroopi rlativ invtigation humidity, h, fratur dgr urfa (ESEM) dgr howd that ilia hort fum fibr ration, an α, b i.. w =w hydration linkd to multifilamnt = ag-dpndnt yarn. Thi might orption/dorption improv th bond btwn (Norling txtil Mjonll and matrix, 1997). thrby Undr lading to mallr by rak ubtituting width and Equation highr raking 1 into Equati thi aum dnity. Figur 6 obtain how th implantation gla hort fibr in multifilamnt yarn in a TRC plat rinford by 4 layr txtil and 0.5% (by volum ontnt) hort gla + fibr. ( D h) = α& + α& + w Th poitiv influn hort fibr on th tr-train bhaviour TRC an b larly notid in th rak-widning whr / i tat th lop (IIb) a th wll. orption/ Whil th train iothrm apaity (alo th ompoit alld moitur wa prrvd, th tnil govrning trngth quation th ompoit (Equation 3) with mut b apa hort fibr i gnrally by appropriat highr than boundary for th and matrial initial onditi without adding hort Th fibr. rlation Sin btwn th tr-train th amount urv for TRC watr with hort and fibr rlativ wr humidity alway abov i alld th orrponding iothrm urv for if TRC maurd without with hort inraing fibr, it an b onludd humidity that and th dorption nrgy aborption iothrm in th (ara undr th a. tr-train Nglting urv) thir inra diffrn ignifiantly du to th th following, addition orption hort fibr. iothrm will b (Xi t al. rfrn to both orption and dorption By th way, if th hytri th iothrm would b takn into aount, two rlation, vaporabl watr v rlativ humi b ud aording to th ign th varia rlativity humidity. Th hap th iothrm for HPC i inflund by many p pially tho that influn xtnt and hmial ration and, in turn, dtrm trutur and por iz ditribution (watrratio, mnt hmial ompoition, SF uring tim and mthod, tmpratur, mix t.). In th litratur variou formulatio found to drib th orption iothrm onrt (Xi t al. 1994). Howvr, in th Figur 6. Short gla fibr linkd to multifilamnt yarn a txtil layr (from papr a TRC th plat mi-mpirial rinford with 4 xprion layr pro txtil and 0.5% hort Norling gla fibr). Mjornll (1997) i adoptd b Proding FraMCoS-7, May 23-28, 2010

5 4.2 J = D ( Th h, diffrn T ) h in fft intgral and (1) diprd hort fibr Figur Th 7 proportionality how th rult fiint th uniaxial D(h,T) tnion i alld tt moitur on TRC prmability pimn and with i 2 txtil a nonlinar layr, funtion with and th without rlativ hort humidity fibr. h Two and typ tmpratur AR-gla T (Bažant fibr & Najjar wr ud 1972). in Th thi moitur tt ri: ma diprd balan and rquir intgral. that th Th variation onntration in tim hort th watr fibr ma wa 1% pr by unit volum. Watr-to-bindr onrt (watr ratio ontnt w) th b mixtur qual to in th th divrgn tt wa th moitur flux J It an b rognid larly from th graph that diprd hort fibr i mor ffiint in inraing = J (2) th t firt-rak trngth TRC in omparion to th intgral fibr. With inraing tr and train lvl Th th watr advantag ontnt w hort an b fibr xprd bgin a to th fad; um until th TRC vaporabl failur th watr tr-train w (apillary urv watr, for watr th plat vapor, with and adorbd and without watr) th and addition th non-vaporabl diprd hort (hmially fibr approah bound) ah watr othr loly. w n (Mill Obviouly 1966, th Pantazopoulo failur probability & Mill 1995). hort diprd It raonabl fibr in-tra aum tadily that th with vaporabl inrad watr loading i a and funtion rak opning. rlativ humidity, It i vry likly h, dgr that grat hydration, majority, αif, not and all dgr th ilia diprd fum ration, fibr, fail α bfor, i.. w th =w (h,α tnil,α ) trngth = ag-dpndnt th ompoit orption/dorption i rahd. iothrm (Norling Th addition Mjonll 1997). th intgral Undr thi hort aumption fibr lad and only by ubtituting to a modrat Equation fft 1 with into rgard Equation to th 2 inra obtain in firt-rak tr but improv th load- on baring apaity TRC ovr th ntir train rang. Th intgral fibr rmain in trand during onrt mixing + ( D and h) onquntly = α& + in α& th + whardnd & n (3) TRC. Th ation th intgral fibr in TRC i imilar to that th multifilamnt yarn. Du to th whr onntration / i th lop th filamnt th orption/dorption th poitiv fft iothrm on firt-rak (alo alld tr i moitur l pronound, apaity). in Th th govrning arrt and quation bridging (Equation miro-rak 3) mut b i l ompltd ffiint by appropriat and in boundary only outr and filamnt initial ondition. th filamnt bundl Th hav rlation a good btwn bonding th amount to th urrounding vaporabl matrix. watr and Howvr, rlativ th humidity intgral i fibr alld rmain adorption ativ iothrm alo at if high maurd dformation. with inraing rlativity humidity A a rult and dorption th hort intgral iothrm fibr in th xhibit oppoit a poitiv a. Nglting fft right thir up diffrn to TRC failur. (Xi t It al. i 1994), n in in th narly following, paralll orption our iothrm tr-train will b ud urv with for rfrn TRC with to both and orption without and addition dorption th ondition. intgral hort By th fibr. way, It i if worthy th hytri mntion that th uh moitur hifting iothrm in would our b takn th urv into indiat aount, two a onidrabl rlation, inra vaporabl in th nrgy watr v whih rlativ an humidity, b diipatd mut diffrnt whn b ud TRC aording with hort to th fibr ign addition th i variation ubjtd to th tnil rlativity loading. humidity. Th hap th orption iothrm Th influn for HPC i th inflund typ hort by many fibr paramtr, on rak formation pially wa tho invtigatd that influn by viual xtnt inption and rat th th hmial pimn ration urfa. and, Th in turn, pimn dtrmin mad por TRC trutur with and addition por iz ditribution diprd (watr-to-mnt hort fibr howd ratio, mnt mor and hmial finr rak ompoition, a wll a SF mor ontnt, uniform uring ditribution tim and mthod, th rak tmpratur, ovr th mix lngth additiv, th t.). pimn In th litratur whn ompard variou formulation with th orrponding found to data drib for TRC th orption with intgral iothrm hort fibr. normal an b Thi onrt rult (Xi aord t al. with 1994). th Howvr, aumption in th onrning papr th th ativ mi-mpirial mhanim xprion th fibr propod addition a by prnt diud Norling Mjornll abov. (1997) i adoptd bau it xpliitly aount for th volution hydration ration and SF ontnt. Thi orption iothrm rad 1 w ( h, α, α ) = G ( α, α ) ( g α α ) h 1 10( g α α ) h K ( α, α ) (4) whr th firt trm (gl iothrm) rprnt th phyially bound (adorbd) watr and th ond trm (apillary iothrm) rprnt th apillary watr. Thi xprion i valid only for low ontnt Figur SF. 7. Th Efft fiint diprd Gand intgral hort gla fibr on 1 rprnt th amount bhaviour TRC plat undr tnion. watr pr unit volum hld in th gl por at 100% rlativ humidity, and it an b xprd (Norling Mjornll 4.3 Influn 1997) a hort arbon fibr Th rult th uniaxial tnil tt on TRC r- ( α, α ) = plat k α mad + k αwith addition diprd (5) Ginford 1 vg vg hort arbon fibr (SCF) ar prntd in thi tion. Th ignifiant influn thi typ hort whr fibr kon vg th and workability k vg ar matrial th paramtr. mixtur i From not diud hr. amount watr pr unit volum that an th maximum fill all Plat por with (both a rlativly apillary high por dgr and gl por), txtil on rinformnt alulat K(4 1 a layr) on obtain and a rlativly low dgr an diprd gla and diprd arbon hort fibr (0.5 % by volum) wr produd and ttd. Figur 8 prnt w th α + tr-train 0.22α G 1 rlation obrvd. g α α Aording to th rult a mor pronound (6) nhanmnt 1 in th bhaviour TRC wa ahivd K ( α, α ) = g α α by th addition th arbon 1 fibr. 1 Th fft wa partiularly vidnt at low train lvl. Th xplanation Th matrial th paramtr finding i k atually vg and k vg quit and traightforward alibratd in by arbon fitting fibr xprimntal ha both data a highr rlvant tnil to g 1 an b fr trngth (vaporabl) and highr watr tiffn ontnt in omparion in onrt to ARgla fibr. ag (Di Luzio & Cuati at variou 2009b). 2.2 Tmpratur volution Not that, at arly ag, in th hmial ration aoiatd with mnt hydration and SF ration ar xothrmi, th tmpratur fild i not uniform for non-adiabati ytm vn if th nvironmntal tmpratur i ontant. Hat ondution an b dribd in onrt, at lat for tmpratur not xding 100 C (Bažant & Kaplan 1996), by Fourir law, whih rad q = λ T (7) whr q i th hat flux, T i th abolut tmpratur, Figur 8. Efft and λ diprd i th hat hort ondutivity; gla fibr (SGF) in thi and hort arbon fibr (SCF) on th bhaviour TRC plat in uniaxial tnion tt. Proding FraMCoS-7, May 23-28, 2010

6 5 SUMMARY AND OUTLOOK Thi artil prnt th prliminary rult a tudy th fft adding diffrnt typ hort fibr on th fratur bhaviour txtil rinford onrt ubjtd to tnil loading. Uniaxial tnion tt wr prformd on TRC pimn with and without th addition hort fibr. Th tr-train urv dmontrat larly th poitiv influn th hort fibr on thir bhaviour undr tnion. For xampl, th firt-rak tr valu wa doubld du to th addition 1.0% by volum diprd hort gla fibr to a TRC plat rinford by two layr txtil. Furthrmor, th nrgy aborption, idntifid by th ara undr th tr-train urv, inrad ignifiantly du to th addition all th typ hort fibr hon for thi invtigation. Howvr, th influn hort fibr on th urv hap dpnd on th partiular fibr typ. Whil th addition diprd AR-gla fibr on th firt-rak tr wa vry pronound, th u th am prntag intgral AR-gla fibr aud only modrat inra thi valu. On th othr hand, th addition intgral hort gla fibr onidrably improvd th tnil trngth TRC, whil th fft diprd fibr on thi paramtr wa l pronound. Firt vry promiing rult wr obtaind for TRC with th addition arbon hort fibr. A rmarkabl inra in th firt-rak tr valu wa maurd vn for a rlativly low onntration diprd hort arbon fibr. Rarh i till in progr and onidrabl xprimntal and thortial ffort ar ndd in ordr to omprhnd th fft diffrnt typ and amount hort fibr in txtil-rinford onrt. A numbr paramtr ombination mut till b invtigatd. Th tting program will b xtndd to polymri fibr, whih ar vry ffiintly ud in Strain-Hardning Cmnt-bad Compoit (Mhthrin 2005). Furthrmor, invtigation matrial mirotrutur will b onidrably intnifid. 6 ACKNOWLEDGEMENTS Th rult wr obtaind in a projt initiatd in th Collaborativ Rarh Cntr SFB 528 Txtil Rinformnt for Strutural Strngthning and Rtritting finand by th Grman Rarh Foundation DFG. Th author would lik to aknowldg with gratitud th foundation finanial upport. REFERENCES J = ) D ( h, T h Barhum, R. 2007: Txtil Th rinford proportionality onrt fiint Tranport D(h,T) mhanim ga and wat., Matr thi, Thnih Univrität moitur Drdn. prmability and it i a nonlina Bramhubr, W. (d.) th rlativ Txtil humidity Rinford h and Conrt. tmpratur Stat--th-Art & Rport Najjar RILEM 1972). Th Thnial moitur Commit ma balan 201-TRC. RILEM that th Rport variation 36, RILEM in tim Publiation th watr ma S.A.R.L. volum onrt (watr ontnt w) b q Butlr, M. t al. 2006: Th influn Short Gla Fibr on divrgn th moitur flux J th Working Capaity Txtil Rinford Conrt. Bangnux: RILEM. In: Txtil Rinford Conrt. Proding th th 1 t Intrnational RILEM Sympoium, = J Aahn, (Hggr, J.; t Bramhubr, W.; Will, N. (Ed.)), pp Butlr, M. t al. 2009: Exprimntal invtigation on th durability fibr-matrix Th watr intrfa ontnt in txtil-rinford w an b xprd a onrt. Cmnt th & Conrt vaporabl Compoit watr 31: w P. (apillary 221 wa 231. vapor, and adorbd watr) and th non- Curbah, M. & J, (hmially F. 2009: Txtil bound) Rinford watr Strutur : Proding Pantazopoulo th 4nd Colloquium & Mill on 1995). Txtil R- It i ra w n (Mil inford Strutur (CTRS4), Drdn. SFB 528, Thnih Univrität Drdn. aum that th vaporabl watr i a fu Hinzn, M. & Bramhubr, rlativ humidity, W. 2007: Influn h, dgr Short Fibr on Strngth, dgr Dutility ilia and Crak fum ration, Dvlopmnt α, i.. w =w hydration Txtil Rinford = ag-dpndnt Conrt. In: Rinhardt, orption/dorption H.W.; Naaman, A.E. (d.): (Norling High Mjonll Prforman 1997). Fibr Undr Rinford thi aum Cmnt Compoit by ubtituting (HPFRCC5): Proding Equation 1 th into 5th Equati Intrnational RILEM Workhop, Mainz, Grmany. Bagnux: RILEM, pp. obtain J, F. 2004: Tragvrhaltn von Filamntgarnn in zmntgbundnr Matrix. Dirtation. Thnih Univrität Drdn. + ( D h) = α& + α& + w Mhthrin, V. (d) 2005: h Ultra-dutil h onrt with hort fibr- Dvlopmnt, Tting, Appliation. ibidm Vrlag. whr / i th lop th orption/ iothrm (alo alld moitur apa govrning quation (Equation 3) mut b by appropriat boundary and initial onditi Th rlation btwn th amount watr and rlativ humidity i alld iothrm if maurd with inraing humidity and dorption iothrm in th a. Nglting thir diffrn (Xi t al. th following, orption iothrm will b rfrn to both orption and dorption By th way, if th hytri th iothrm would b takn into aount, two rlation, vaporabl watr v rlativ humi b ud aording to th ign th varia rlativity humidity. Th hap th iothrm for HPC i inflund by many p pially tho that influn xtnt and hmial ration and, in turn, dtrm trutur and por iz ditribution (watrratio, mnt hmial ompoition, SF uring tim and mthod, tmpratur, mix t.). In th litratur variou formulatio found to drib th orption iothrm onrt (Xi t al. 1994). Howvr, in th papr th mi-mpirial xprion pro Norling Mjornll (1997) i adoptd b Proding FraMCoS-7, May 23-28, 2010