Durability performance of UFC sakata-mira footbridge under sea environment

Transcription

1 Fratur Mhani of Conrt and Conrt Strutur - High Prforman, Fibr Rinford Conrt, Spial Loading and Strutural Appliation- B. H. Oh, t al. (d) 2 Kora Conrt Intitut, ISBN Durability prforman of UFC akata-mira footbridg undr a nvironmnt Y. Tanaka & H. Muha Taii Corporation, Tokyo, Japan S. Tanaka & M. Ihida Taihiyo Cmnt Corporation, Tokyo, Japan ABSTRACT: Sakata-Mirai Footbridg ha bn ompltd for th firt tim in Japan uing ultra high prforman fibr rinford onrt, brand nam Dutal in Otobr 22. Th loation of thi footbridg i about 3.4 km from th Japan Sa oatlin thrfor thi footbridg ha bn xpod to vr orroiv nvironmnt in intr. In thi papr th diffuion offiint of hlorid ion and th mhanial proprti r invtigatd form th fild obrvation. Alo th por iz ditribution invtigation applying th mrury intruion poroimtry apparatu r arrid out in th laboratory. Th advantag of th lif yl ot of UHPFRC trutur in hlorid ion attak i diud. INTRODUCTION Th brand nam Dutal i on of th mot applid Ultra High Prforman Fibr Rinford Conrt (abbrviatd to UFC) matrial for atual trutur uh a bridg, building, tunnl lining and o on in th orld. Rnt tn yar, around tnty trutur r ontrutd applying Dutal in Japan. A Dutal i n gnration onrt matrial poing high trngth, high dutility, high fluidity and high durability, it i poibl to dratially rdu th dad ight of th bridg ompard to tho mad of ordinary onrt and thi an rdu th total ontrution ot inluding th foundation ot pially in arthquak ountri lik Japan. Furthrmor, th maintnan ot an b avd du to it high durability prforman. In 22, a 5 m pan "Sakata-Mirai Footbridg" (Tanaka t al. 22) ha bn ontrutd in Sakata City applying Dutal for th firt tim in Japan a hon in Photograph. Bad on thi ahivmnt and laboratory tt data, "Rommndation for Dign and Contrution of Ultra High Strngth Fibr Rinford Conrt Strutur, -Draft" (JSCE 24) a publihd in 24 by Japan Soity of Civil Enginr. Aftr th publiation, th dign and ontrution rord of footbridg, highay bridg, railay bridg and arhittural trutur mad of UFC hav bn inraing for rnt fiv yar in Japan. Thi footbridg i loatd in Sakata City faing to th Japan Sa and th it loation i about 3.4 km Photograph. Compltion of Sakata-Mirai Footbridg. from th Japan Sa oatlin. Th footbridg habn attakd by vr orroiv ind in intr. In ordr to prov that th footbridg ould not nd any maintnan, author hav bn invtigating th durability bhavior and it mhanial trngth prforman of th footbridg through monitoring th tt pimn xpod inid th box girdr of th footbridg. 2 CONSTRUCTION OF FOOTBRIDGE 2. Sit loation Th footbridg i loatd in Sakata City, Yamagata prftur faing to th Japan Sa. Th loation map of thi footbridg i hon in Figur. Th t oatlin in Japan uually ha vr t or outh

2 Japan Sa Mogami Rivr Sakata City Hall Sakata Mirai Foot- frquny = ) D ( h, T h ampl data N=48 avrag 96 N/mm2 tandrd dviation 7. N/mm ompriv trngth (N/mm 2 = J ) Figur 2. Compriv trngth t frquny. J Th proportionality offiint D(h,T) moitur prmability and it i a nonlina of th rlativ humidity h and tmpratur & Najjar 972). Th moitur ma balan that th variation in tim of th atr ma volum of onrt (atr ontnt ) b q divrgn of th moitur flux J Figur. Sit loation map of footbridg. Tabl. Compoition of Dutal. mixd ingrdiant upr (mnt, ilia atr fibr W/C platizr unit fum, quartz, t) kg/m t ind and noy torm in intr. Although th it loation i 3.4 km far from th oatlin, th aonal intr torm indu th hlorid attak on th footbridg. 2.2 Matrial prforman applid for footbridg Th formulation of Dutal applid for Sakata-Mirai Footbridg i hon in Tabl. Th major prinipl ar a follo; ) minimum of dft uh a miro-rak and por pa by xtrmly lo atr/mnt ratio (=22%), 2) nhanmnt of ompatd dnity by optimization of th granular mixtur, 3) nhanmnt of th mirotrutur by hat tratmnt, and 4) nhanmnt of dutility by inorporating tl fibr. Th lf-lvling prforman i ahivd that a flo valu (JIS-R-522.) i around mm for th matrial tmpratur of 2~25 o C vn for inluding th tl fibr (.2 mm in diamtr, 5 mm in lngth) by 57 kg/m 3 (2% in vol.) in th matrix. Thrfor it i poibl to at it into th vry thin hll mold or into th ompliatd hapd mold. Th grgation or inking of tl fibr from th matrix do not our bau of th viouity of th pat. Hovr it i notd that th orintation of th tl fibr hould b ontrolld to ditribut in all dirtion hn ating. Th mixing plant for th fabriation of pr-at gmnt a an ordinary pan typ mixr. For th mhanial quality managmnt of th matrial, 6 tt ylindrial pimn ith th iz of φx2 m for ompriv trngth and 3 tt pimn ith th iz of xx4 m for flxural trngth r ampld for ah pr-at gmnt. All -6 μmth atr ontnt an b xprd a - of μmth vaporabl atr (apillary a 9.5- vapor, μm G.P.=gl and adorbd por atr) and th non- 8-5 nm (hmially C.P.=apillary bound) por atr n (Mil 7 - nm 6- Pantazopoulo nm & Mill 995). It i ra nm aum that th vaporabl atr i a fu 5 C.P. rlativ humidity, h, dgr of hydration C.P. 4 C.P. dgr of ilia fum ration,, i.. = 3 = ag-dpndnt orption/dorption 2 (Norling G.P. Mjonll G.P. 997). Undr thi aum by ubtituting Equation into G.P. Equati obtain Dutal, Dutal, W/C 3%, hat uring uring in atr uring in atr h + 9d ( D h) = 9d & + & + h t h Figur 3. Comparion of por volum ratio. por volum ratio (%) hr.4 /h i th lop of th orption/ Dutal, hat iothrm (alo alld uring moitur apa.2 govrning quation (Equation 3) mut b Dutal, uring in by appropriat boundary atr 9d and initial onditi Th rlation btn th amount of W/C3%, uring in.8 atr and rlativ atr humidity 9d i alld iothrm if maurd ith inraing.6 humidity and dorption iothrm in th.4 a. Nglting thir diffrn (Xi t al. th folloing, orption iothrm ill b.2 rfrn to both orption and dorption By th ay, if th hytri of th.. iothrm.ould b takn into aount, to rlation, vaporabl atr v rlativ humi por diamtr (μm) b ud aording to th ign of th varia Figur 4. Por volum rlativity ratio ditribution. humidity. Th hap of th ampl ith 9 o iothrm for HPC i inflund by many p pially C hat tratmnt tho that for 48 influn hour r xtnt and urd in th am hmial ay a th ration pr-at gmnt. and, in turn, Figur 2 indiat th trutur frquny and por ditribution iz ditribution of om-(atrpriv trngth hoing th man valu i 96 dtrm N/mm 2 ratio, mnt hmial ompoition, and th tandard dviation i 7. N/mm 2 SF uring tim and mthod, tmpratur, for mix th data numbr N=48. t.). In On th litratur othr hand, variou th rult formulatio of flxural trngth a that th man valu i 36.5 N/mm 2 found to drib th orption and th tandard dviation i 4.5 N/mm 2 iothrm onrt (Xi t al. 994). Hovr, for in th th data numbr N=24. papr th mi-mpirial xprion pro Norling Mjornll (997) i adoptd b por volum ratio (%) Proding of FraMCoS-7, May 23-28, 2

3 J = D ( h, T ) h () xpliitly aount for th volution of hydration (urfa) (t.%) (kg/m 3 ) (urfa) ration (t.%) and (kg/m 3 SF ) ontnt. (urfa) Thi orption (t.%) iothrm (kg/m 3 ) Th proportionality offiint 3.4D(h,T) i alld rad moitur prmability and it i a.6 nonlinar funtion of th rlativ humidity h and tmpratur 9.8 T (Bažant & Najjar 972). Th moitur ma 7.7 balan rquir ( h 5.7,, ) = G ( 5.7, ) +.3 that th variation in tim of th atr ma pr unit ( g ) h 5.2 volum of onrt (atr ontnt 2.) b qual to th (4) divrgn of th moitur flux J... ( g ) h K ( ) Figur 6. Chlorid ion onntration ditribution for diffrnt immrd priod maurd by, Eltron Prob Miro Analyzr. = J (2) t Tabl 2. Apparnt hlorid ion diffuion offiint. 2 3 (mm) 8 Th atr ontnt an b xprd a th um 7.5 yar of th vaporabl atr (apillary atr, atr vapor, and 6 adorbd atr) and th non-vaporabl.5 yar (hmially 5 bound) atr n (Mill 2.5 yar966, Pantazopoulo 4 & Mill 995). It i raonabl to aum 3that th vaporabl atr i a funtion of rlativ humidity, h, dgr of hydration, 2, and hlorid ion onntration (kg/m 3 ) dgr of ilia fum ration,, i.. = (h,, ) = ag-dpndnt orption/dorption iothrm (Norling Mjonll 997). Undr thi aumption and by ubtituting Equation 2 into 3 Equation 4 2 on 5 obtain ditan from urfa (mm) Figur 5. Chlorid profil aftr diffrnt priod. h Th inorporation + ( D h) of = mall-iz & + tl & fibr + & rult n (3) h t h in ultra-high nrgy aborption apabiliti. Th bnding fratur nrgy i 36, Nm/m 2, on th othr hr hand /h on i th for lop th of ordinary th orption/dorption onrt ith ompriv iothrm (alo trngth alld 3~5N/mm moitur 2 apaity). i at mot Th a rang govrning of 5~2Nm/m quation (Equation 2. Th 3) high-tnil mut b ompltd trngth ombind by appropriat ith boundary th high dutility and initial mak ondition. onvntional rinformnt Th rlation unnary. btn th amount of vaporabl atr Th and matrix rlativ of Dutal humidity form i alld a dn adorption trutur du iothrm to dnt if maurd paking ith and inraing mirotrutur rlativity rulting humidity from and pozzolani dorption ration iothrm of ilia in th fum. oppoit Th por a. iz Nglting ditribution thir of diffrn Dutal (Xi i thrfor t al. 994), quit in diffrnt th folloing, from orption th ordinary iothrm onrt. ill b Figur ud ith 3-4 ho rfrn th to omparion both orption of por and dorption iz ditribution ondition. btn By th Dutal ay, and if th th hytri ordinary high of trngth th moitur onrt iothrm ith ould W/C=3%. b takn Th into rlationhip aount, to btn diffrnt th por rlation, volum vaporabl ratio and atr th v por rlativ diamtr humidity, a mut prditd b ud by aording applying to a mrury th ign of intruion th variation poroimtry of th apparatu. rlativity Th humidity. por trutur Th hap i dignatd of th dpnding iothrm on th for por HPC iz; i inflund i.. it i dfind by many a paramtr, Gl Por orption for pially th iz tho up to that nm influn on th xtnt othr hand rat it i of dfind hmial a Capillary ration Por and, for in th turn, iz dtrmin from nm por to th µm. trutur Th and apillary por iz por ditribution a ontinuou (atr-to-mnt por lik amba ratio, mnt and thi hmial i rlatd ompoition, to th atr prmability; SF ontnt, i.. uring th tim lr and th mthod, apillary tmpratur, por th bttr mix durability. additiv, It t.). i obviou In th that litratur Dutal variou i xtrmly formulation dnr an trutur found than to th drib ordinary th onrt, orption a iothrm Figur 3 of hoing normal b that onrt th por (Xi volum t al. 994). ratio of Hovr, Dutal for in ithr prnt hat uring papr or th uring mi-mpirial in atr ar xprion %, hn propod that for by high Norling trngth Mjornll onrt (997) ith W/C=3% i adoptd i 9.%. bau it 2 3 (mm) 2 3 (mm) hr th firt trm (gl iothrm) rprnt th phyially immrd priod bound (yar) (adorbd).5 atr.5and th 2.5ond trm (apillary iothrm) rprnt th apillary apparnt hlorid atr. Thi xprion i valid only for lo ontnt of SF. diffuion Th offiint off..59 G rprnt.22th amount.9 of atr (m pr 2 unit /yar) volum hld in th gl por at % rlativ humidity, and it an b xprd (Norling Mjornll 997) a In addition, th por volum ratio of apillary por of Dutal i only.5%, hn that for high onrt i G5.8%. (, ) = k + k (5) vg vg Carrying out frzing and thaing yl in aordan ith JIS A 624 produ no advr fft hr on kth vg and pimn; k vg ar matrial i.. no rlativ paramtr. dynami From lati maximum modulu amount rdution of atr for pr unit yl. volum Th xtrm that an th dnn fill all por of (both Dutal apillary mak por it diffiult and gl to por), dtrmin on th an diffuion alulat offiint K a on obtain of hlorid ion. For th timation of hlorid diffuion offiint, th pimn ith xx4 m a immrd in a NaCl olution (.9%.88 onitny) +.22 for G oupl of yar and g EPMA (Eltron Prob Miro Analyzr) a ud to (6) K (, ) = prdit th apparnt hlorid diffuion offiint g through th rgrion urv to fit th hlorid onntration ditribution nar th pimn urfa. Figur Th 5 matrial dmontrat paramtr th hlorid k ion onntration b alibratd profil aftr by fitting diffrnt xprimntal immrd data priod. rlvant Th to vg and k vg and g an pixl fr (vaporabl) iz a.2 atr mm and ontnt vry in fiv-pixl onrt data r variou avragd ag (Di in Luzio dpth & dirtion; Cuati 29b). i.. th intrval of avragd data in Figur 5 i. mm. Th hlorid onntration ditribution maurd by EPMA for diffrnt 2.2 Tmpratur immrd volution priod i illutratd in Figur 6. Th Not rgrion that, at arly urv ag, to in fit th th hlorid hmial ion ration onntration aoiatd dignat ith mnt th apparnt hydration hlorid and diffuion SF ration offiint ar xothrmi, for tho th diffrnt tmpratur immrd fild i priod. not uniform Th hlorid for non-adiabati diffuion ytm offiint vn if dtrmind th nvironmntal by thi mthod tmpratur ar hon i ontant. in Tabl Hat 2. Tho ondution rult an imply b th dribd apparnt in onrt, diffuion offiint ranging from.9 to.59m 2 at lat for tmpratur not xding C (Bažant /yar. For & omparion, Kaplan 996), th valu by for Fourir onvntional la, hih high rad trngth onrt ith W/C=3%, hih i rgardd a having rlativly high durability, i.4 m 2 q = λ T /yar. Th durability proprti of Dutal (7) thrfor ho a triking diffrn from tho of th onvntional normal onrt. hr q i th hat flux, T i th abolut tmpratur, and λ i th hat ondutivity; in thi Proding of FraMCoS-7, May 23-28, 2

4 Right Bank 255 3R D-R- J = D ( h, T ) h? Th proportionality offiint D(h,T) moitur prmability and it i a nonlina 2R R L 2L 3L of th rlativ humidity h and tmpratur & Najjar 972). Th moitur ma balan that th variation in tim of th atr ma volum of onrt (atr ontnt ) b q N.W.L divrgn of th moitur flux J D-L- Lft Bank = JD-L-2 t Figur 7. Pr-at gmnt ompoition and athti obrvation point of dontram id. Th atr ontnt an b xprd a of th vaporabl atr (apillary a vapor, and adorbd atr) and th non- (hmially bound) atr n (Mil Pantazopoulo & Mill 995). It i ra aum that th vaporabl atr i a fu rlativ humidity, h, dgr of hydration dgr of ilia fum ration,, i.. = = ag-dpndnt orption/dorption (Norling Mjonll 997). Undr thi aum by ubtituting Equation into Equati obtain Photograph 2. Stion of R pr-at gmnt. 2.3 Dign onpt of footbridg Sakata-Mirai Footbridg a pland to rpla four pan old pr-trd onrt pdtrian bridg that a built about 45 yar ago roing ovr th Niita Rivr loatd in Sakata City. Thrfor, th folloing rtrition r rqutd to mak dign and to ontrut th n bridg; i.. ) th ground lvl or th ground lop hould not b hangd, 2) th bridg bottom lin hould not b l than.6 m from th high atr lvl and 3) th longitudinal lop of th bridg hould b l than 5%. From th point of vi of rivr managmnt and th prvntion of boat from ruh aidnt, old pir for bridg r rqutd to mov and on long pan bridg i hon to dign. Bau of th thr rtrition dribd abov, th bridg hight at both nd hould b l than 55m. In ordr to tak th full advantag of th haratriti of UFC and pially to u it ithout any paiv rinformnt, th trutural onpt and uniqu point of Sakata-Mirai Footbridg ar a follo; i.. ) all pr-tring abl r t outid of th ro tion ith dviator, 2) ultimat thin lab (5m) and b (8m) r mployd to rdu th lf dad ight, 3) th prforatd b r mployd for th ak of dign vi and rdution h + ( D h) = h t h Photograph 3. Intallation of 3L pr-t gmnt. hr /h i th lop of th orption/ iothrm (alo alld moitur apa govrning quation (Equation 3) mut b by appropriat boundary and initial onditi Th rlation btn th amount of atr and rlativ humidity i alld iothrm if maurd ith inraing humidity and dorption iothrm in th a. Nglting thir diffrn (Xi t al. th folloing, orption iothrm ill b rfrn to both orption and dorption By th ay, if th hytri of th iothrm ould b takn into aount, to rlation, vaporabl atr v rlativ humi b ud aording to th ign of th varia Photograph 4. Expod rlativity pimn humidity. inid girdr. Th hap of th iothrm for HPC i inflund by many p of dad ight, pially 4) ight tho pr-at that gmnt influn r xtnt and tranvrly and hmial longitudinally ration onntd and, in to turn, ah dtrm othr by t joint trutur and 5) and no paiv por iz rinformnt ditribution (atrratio, by rbar vn for th pr-tring mnt hmial anhorag. ompoition, SF Th pr-at gmnt uring tim ar and ompod mthod, of tmpratur, to typ mix of gmnt a hon in Figur 7; i.. on i lodform ro-tion dfind by L, 2L, R and 2R. t.). In th litratur variou formulatio found to drib th orption iothrm Anothr on i dfind by 3L or 3R that ar ompod of to ymmtrial gmnt bing dividd onrt (Xi t al. 994). Hovr, in th papr th mi-mpirial xprion pro into half at th ntr of th ro tion. Th total Norling Mjornll (997) i adoptd b dad ight rultd in 56kN and th total UFC & + & + Proding of FraMCoS-7, May 23-28, 2

5 J = ) D ( h, T h D-L-2 m 7.5 m Th atr ontnt an b xprd a th um Photograph of th vaporabl 5. Athti atr obrvation (apillary making of atr, D-L-2 and atr D- L-2 vapor, on dontram and adorbd id. atr) and th non-vaporabl (hmially bound) atr n (Mill 966, Pantazopoulo 22 & Mill 995). It i raonabl to aum that th vaporabl atr i a funtion of rlativ humidity, 25 h, dgr of hydration,, and dgr of 2 ilia fum ration,, i.. = (h,, ) = ag-dpndnt orption/dorption iothrm 25 (Norling Mjonll 997). Undr thi aumption and by ubtituting 2 Equation into Equation 2 on obtain 95 9 h + 85 ( D h) = & + & + & n (3) h t h hr /h i th lop of th orption/dorption iothrm (alo xpod alld moitur priod (month) apaity). Th Figur govrning 8. Tim quation hitory rord (Equation of ompriv 3) mut trngth. b ompltd by appropriat boundary and initial ondition. volum Th bam rlation 22m btn 3 du th to th amount thnial of vaporabl dign ffort atr and matrial rlativ humidity advantag. i alld If ordinary adorption prtrd iothrm onrt if maurd r applid ith for inraing thi bridg, rlativity thn th humidity total dad and ight dorption ould iothrm bom 278kN. in th oppoit a. Nglting thir diffrn (Xi t al. 994), in th folloing, orption iothrm ill b ud ith 2.4 Fabriation and intallation of gmnt rfrn to both orption and dorption ondition. Th By lod th ay, form if pr-at th hytri gmnt a of hon th moitur in Photograph iothrm 2 ould ha om b takn irular into hol aount, in th to b. diffrnt Thi gmnt rlation, vaporabl a fabriatd atr by v rlativ ating humidity, UFC at on. mut Thrfor b ud aording th innr to mold th ign for of thi th gmnt variation i of fixd th ith rlativity th outr humidity. mold by Th bolt hap through of th orption irular hol. iothrm Aftr for prliminary HPC i inflund uring a by many prformd paramtr, for 48 hour pially at 3tho o C, th that gmnt influn pimn xtnt and a rat rlad of th from hmial th mold ration and it and, a thn in turn, ubjtd dtrmin to 48 hour por hat trutur tratmnt and por at 9 iz o C. ditribution Photograph (atr-to-mnt 3 dmontrat th ratio, intallation mnt hmial of 3L gmnt ompoition, that ha alrady SF ontnt, bn onntd uring tim latrally and mthod, by to tmpratur, ymmtrial mix gmnt additiv, and bn t.). pr-trd In th litratur by S2.7 variou mono-trand, formulation that uppli an b about found kn/tndon to drib th pr-trd orption iothrm for. Th of normal dad ight onrt of (Xi pr-at t al. gmnt 994). Hovr, a rangd in from th prnt 57 to 35kN, papr th thrfor mi-mpirial,6kn apaity xprion truk propod ran a by ud Norling to intall Mjornll ix gmnt (997) ith i 3 adoptd mm gap bau and it it ompriv trngth (N/mm 2 ) () Th proportionality offiint D(h,T) i alld moitur prmability and it i a nonlinar funtion of th rlativ humidity h and tmpratur T (Bažant & Najjar 972). Th moitur ma balan rquir that th variation in tim of D-L- th atr ma pr unit volum of onrt (atr ontnt ) b qual to th divrgn of th moitur flux J t = J (2) xpliitly aount for th volution of hydration ration and 5 SF ontnt. Thi orption iothrm rad ( h,, 3) = G (, ) + ( g ) h 25 (4) 2 ( g ) h 5 K (, ) max flxural trngth 5 firt raking trngth hr th firt trm (gl iothrm) rprnt th phyially bound (adorbd) atr and th ond trm (apillary iothrm) rprnt th apillary atr. Thi xprion xpod i valid priod only (month) for lo ontnt of SF. Th offiint G Figur 9. Tim hitory rord of rprnt th amount of flxural trngth. atr pr unit volum hld in th gl por at % took rlativ on humidity, day to intall and all it an gmnt. b xprd Aftr UHPFRC (Norling for Mjornll t joint 997) bing a urd by hat tratmnt du to ltri hatr, th longitudinal pr-tring a arrid G (, out ) = by k to t + k of 3S5.2 tndon (5) firt raking and flxural trngth (N/mm 2 ) vg vg 3 hr FIELD k vg OBSERVAION and k vg ar matrial paramtr. From th maximum amount of atr pr unit volum that an 3. fill all Sular por ditortion (both apillary of mhanial por and proprti gl por), on an alulat K a on obtain In ordr to invtigat th matrial tim hitory of mhanial proprti and durability, UFC pimn r xpod inid of th box g girdr of th footbridg a hon in Photograph G 4. Th dimnion of th pimn for ompriv trngth i φ5x (6) K (, ) = m irular ylindr and gthat for flxural trngth i 4x4x6 m rgular prim. Th rult of ompriv trngth vru xpoing duration tim i hon in Figur Th matrial 8 and tho paramtr of flxural k vg and trngth k vg and and g firt an raking b alibratd trngth by fitting ar hon xprimntal in Figur data 9. rlvant Th ompriv fr (vaporabl) trngth m atr to ontnt b gradually in onrt inraing at to but variou it an ag b (Di aid Luzio that & th Cuati trngth 29b). i tabl. It i notd that th avrag ompriv trngth in Figur Tmpratur i largr than volution that in Figur 2. Thi i bau of th iz fft on trngth; i.. th iz of pimn Not that, in Figur at arly 8 i ag, mall. in Th th tim hmial dpndnt ration rord aoiatd of th ith flxural mnt trngth hydration ar alo and SF tabl. ration Th trngth ar xothrmi, of ordinary th tmpratur onrt ha fild uually i not th uniform upard trnd for non-adiabati in tim, hovr ytm UFC vn had if hat th nvironmntal uring in th pro tmpratur of fabriation; i ontant. thrfor Hat th ondution hmial an hydration dribd ha alrady in onrt, ompltd. at lat Thi for man tmpratur th trngth not b ould xding not largly C inra. (Bažant & Kaplan 996), by Fourir la, hih rad 3.2 q = Athti λ T hang du to hlorid attak (7) Th urfa athti hang of th footbridg hav bn hr invtigatd. q i th Th hat obrvation flux, T i point th of abolut inid b tmpratur, urfa blong and λ to i th pr-at hat ondutivity; gmnt L, in R, thi Proding of FraMCoS-7, May 23-28, 2

6 Numbr of rut pot in mx7.5 m ara Expod priod (month) Figur. Tim hitory rord of rut pot dnity. hlorid ion onntration (kg/m 3 ) U-R- U-L- D-R- D-L- D-L-2 EPMA rult rgrion urv dpth (mm) Figur. Chlorid ion onntration and rgrion urv. 2L and 2R. On th othr hand, tho of outid b urfa blong to th pr-at gmnt 3L and 3R. Th invtigation on athti hang (hang of tiny rut pot) r ondutd by taking pitur through th making fram ith x7.5 m and ounting th rut pot numbr ithin th making fram. Th inption rult of athti hang i hon in Figur. Th athti obrvation point ar illutratd in Figur 7. Rut pot on th urfa r not found inid b urfa, but found outid b urfa. Compard th dontram id b and th uptram id b, it i obviou that th rut pot dnity on th dontram id b i havir than th uptram id. Th raon i that th dontram id b hav bn attakd vr orroiv ind and torm in intr. Th rut pot dnity on th dontram id b ho tndny to gradually inra, hovr any dtrioratd hang on th matrix ould not bn n around th rut pot for 5 yar xpod duration tim. In addition, th atual athti grad m to b ngligibl. Photograph 5 a takn m aay from th fa of D-L- and D-L-2 pot and it i diffiult to priv th rut pot ith yight. Th rut pot m to b gnratd hn om tl fibr rmain nar th urfa. hlorid J = D ( h, T ) h ight % ilion alium ulfur Th proportionality offiint D(h,T) moitur prmability and it i a nonlina of th rlativ humidity h and tmpratur & Najjar 972). Th moitur ma balan that th variation in tim of th atr ma volum of onrt (atr ontnt ) b q divrgn of th moitur flux J t = J Th atr ontnt an b xprd a quartz grain of th vaporabl atr (apillary a vapor, and adorbd atr) and th non- tl (hmially fibr bound) atr n (Mil Pantazopoulo & Mill 995). It i ra aum that th vaporabl atr i a fu rlativ humidity, h, dgr of hydration dgr of ilia fum ration,, i.. = = ag-dpndnt orption/dorption (Norling Mjonll 997). Undr thi aum by ubtituting Equation into Equati obtain h + ( D h) = h t h & + & + hr /h i th lop of th orption/ iothrm (alo alld moitur apa govrning quation (Equation 3) mut b by appropriat boundary and initial onditi Th rlation btn th amount of atr and rlativ humidity i alld iothrm if maurd ith inraing Figur 2. Chlorid, humidity Silion, Calium and dorption and Sulfur onntration iothrm in th profil maurd by EPMA. a. Nglting thir diffrn (Xi t al. th folloing, orption iothrm ill b For xampl hn rfrn th matrix to both ovr orption thikn and dorption i zro or -2 µm, By tiny th pot ay, of tl if th fibr hytri rat ith of th hlorid iron, atr iothrm and oxygn. ould b Hovr, takn into bau aount, to matrix around th rlation, tl fibr vaporabl i xtrmly atr dn v rlativ and humi hard to intrud hlorid b ud aording ion, orroion to th ould ign of not th varia progr furthr mor. rlativity humidity. Th hap of th iothrm for HPC i inflund by many p pially tho that influn xtnt and 3.3 Chlorid ion onntration profil hmial ration and, in turn, dtrm Th pimn ith trutur 4x4x6 and m por rgular iz ditribution prim that (atrratio, month mnt (about hmial 5 yar) inid ompoition, th SF a xpod for 6 box hapd girdr, uring a tim lid and off mthod, mm tmpratur, thikn. mix Th dimnion of t.). th tt In urfa th litratur a takn variou to b formulatio mm in idth and found 5 mm to in drib dpth from th orption th urfa iothrm and thi pi a onrt grindd (Xi to t apply al. 994). EPMA. Hovr, Th in th hlorid ion onntration papr th mi-mpirial profil and th xprion rgrion urv ar illutratd Norling in Mjornll Figur. (997) Th pixl i iz adoptd pro b Proding of FraMCoS-7, May 23-28, 2

7 a J = D (.2 h, T ) mm h and vry 5 pixl data r avragd () in dpth dirtion. Th rgrion data a takn at dpr Th point proportionality of.4 mm. offiint It hould D(h,T) b notd i alld that ompard moitur prmability to th tt pimn and it i that a nonlinar a immrd funtion in a of NaCl th rlativ olution humidity (hon in h and Fig. tmpratur 5), thi onntration T (Bažant profil & Najjar of 972). th hlorid Th moitur ion mooth ma balan and fit rquir th rgrion that th variation urv quit in ll. tim of From th th atr rgrion ma pr funtion, volum th of apparnt onrt hlorid (atr ontnt ion diffuion offiint unit a prditd to b.48 m 2 ) b qual to th divrgn of th moitur flux J /yar that i vry mall ompard to th immrd a and th hlorid ion onntration on th urfa a alulatd to b = 8.9 Jkg/m 3. (2) t Figur 2 indiat th hlorid, ilion, alium and ulfur ditribution obtaind by EPMA. Whn Th atr ontnt an b xprd a th um ompard tho four pitur, not only th hlorid of th vaporabl atr intruion but alo th tl (apillary atr, atr fibr, quartz grain, and vapor, and adorbd atr) and th non-vaporabl hydrat ubtan an b idntifid. For xampl, (hmially bound) atr from th rult of ilion pitur, n (Mill 966, mall blak dot Pantazopoulo & Mill 995). It i raonabl to mut b tl fibr, larg irular blak dot mut b aum that th vaporabl atr i a funtion of ntrappd air, hit polygon mut b quartz grain rlativ humidity, h, dgr of hydration, and rt of ylloih grn mut hydrat ubtan., and dgr of ilia fum ration, It hould b notd that orroiv, i.. nvironmnt = (h, of, thi ) = ag-dpndnt orption/dorption iothrm footbridg may b muh vr than hat onidrd in dign tag from th information that th (Norling Mjonll 997). Undr thi aumption and by ubtituting Equation into Equation 2 on hlorid ion onntration on th urfa a drivd to b 8.9 kg/m 3 obtain. h + ( D h) = & + & + & n (3) 4 CONCLUSIONS h t h ) Th tim dpndnt rord of ompriv and hr flxural trngth /h i th lop of th orption/dorption r tabl. iothrm (alo alld moitur apaity). Th 2) Athti hang on th UFC urfa ould not govrning quation (Equation 3) mut b ompltd b obrvd xpt th dontram outid b by appropriat boundary and initial ondition. hr hlorid ion may b onntratd. Th rlation btn th amount of vaporabl 3) Rut pot r atually hard to find out ith yight and no dtrioratd hang on th matrix atr and rlativ humidity i alld adorption iothrm if maurd ith inraing rlativity ould b obrvd around th rut pot. humidity and dorption iothrm in th oppoit 4) Chlorid ion diffuion offiint obtaind th a. Nglting thir diffrn (Xi t al. 994), in fild pimn a muh lor than that in th laboratory immrd pimn. th folloing, orption iothrm ill b ud ith rfrn to both orption and dorption ondition. By th ay, if th hytri of th moitur iothrm ould b takn into aount, to diffrnt PREFERENCES rlation, vaporabl atr v rlativ humidity, mut JSCE b ud 24. aording Rommndation to th for ign Dign of th and variation Contrution of th Ultra High humidity. Strngth Fibr Th Rinford hap Conrt of th Strutur- orption rlativity iothrm Draft. Conrt for HPC Library i inflund No 3. by many paramtr, Tanaka, pially Y. & tho Muha, that H. influn & Ootak, xtnt A. & Shimoyama, and rat of Y. th & hmial Kanko, O. ration 22. Dign and, and in Contrution turn, dtrmin of Sakata Mirai por Footbridg uing Rativ Podr Conrt, Pro. of t fib trutur and por iz ditribution (atr-to-mnt Congr 22, Ooaka. ratio, mnt hmial ompoition, SF ontnt, uring tim and mthod, tmpratur, mix additiv, t.). In th litratur variou formulation an b found to drib th orption iothrm of normal onrt (Xi t al. 994). Hovr, in th prnt papr th mi-mpirial xprion propod by Norling Mjornll (997) i adoptd bau it xpliitly aount for th volution of hydration ration and SF ontnt. Thi orption iothrm rad ( h,, ) = G (, ) + ( g ) h ( g ) h K (, ) (4) hr th firt trm (gl iothrm) rprnt th phyially bound (adorbd) atr and th ond trm (apillary iothrm) rprnt th apillary atr. Thi xprion i valid only for lo ontnt of SF. Th offiint G rprnt th amount of atr pr unit volum hld in th gl por at % rlativ humidity, and it an b xprd (Norling Mjornll 997) a G (, ) = k + k vg vg (5) hr k vg and k vg ar matrial paramtr. From th maximum amount of atr pr unit volum that an fill all por (both apillary por and gl por), on an alulat K a on obtain K (, ) = g G g (6) Th matrial paramtr k vg and k vg and g an b alibratd by fitting xprimntal data rlvant to fr (vaporabl) atr ontnt in onrt at variou ag (Di Luzio & Cuati 29b). 2.2 Tmpratur volution Not that, at arly ag, in th hmial ration aoiatd ith 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 C (Bažant & Kaplan 996), by Fourir la, hih rad q = λ T (7) hr q i th hat flux, T i th abolut tmpratur, and λ i th hat ondutivity; in thi Proding of FraMCoS-7, May 23-28, 2