Special Topics CEE 8813
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Creep of UltraHigh Performance Concrete UHPC Victor Y Garas CEE 8813 04 13 2007 School of Civil and Environmental Engineering Georgia Institute of Technology Atlanta GA 30332 Presentation Organization UltraHigh Performance Concrete Definition Developing Advantages Applications Creep of Concrete Definitions Mechanisms Creep of UltraHigh Performance Concrete Compressive Tensile Motivation Tensile Background Tensile Test Setups Tensile Key Results Concluding Remarks UHPC Definitions ACI Committee 116 quotA concrete meetin secial combinations of performance and uniformity requirements that cannot alwa K be achieved routinel using conventional constituent materials and normal mixing placing and curing practices The Federal Highway Administration FHWA quotHPC can be speci ed not on K the strenth but by also the following freezethaw durability scaling resistance abrasion resistance chloride penetration cree shrinkage and modulus of elasticity UHPC Definitions Collepardi et al 1997 quotUHPC can be defined as an ultrahih strenth and hih ductili concrete with advanced mechanical properties Shah and Weiss 1998 UltraHigh Strength Concrete UHSC is defined as a mixture with comressive strenth reater than 22 ksi 150 MPa 2 UHPC Developing 1 Decreasing Permeability Maximum aggregagt w v O Reducing the watercement 120 ratio typically lt 02 i E 100 it 92 E Providing proper compaction 9 p U vibration E 80 E i 8 o a 60 E Eliminating Coarse aggregates 1 4g 3 40 E 20 0 4P 1 l 0 74 05 06 07 08 09 Watercement ratio Imae from Mehta and Monteiro 2005 UHPC Developing 2 Densification with microfine particles Filling reaining v0id space I r a 791 H l Edi 1 quot quotyr 3933 7 3 393 5quot WEE f zgquot ivr ham Denser material whicifg ffl i i g i u l 139 1 Stronger and more durable material Imae from httptechalivemtuedumeecmodule06Packinghtm UHPC Developing 3 Macrodefect free MDF Materials Cement Watersoluble polymer low wc typically less than 02 Increase in strength arises as a result of the crosslinking between cement and polymer Poyola et al 1990 4 Using Fibers V 39enllu Elli Coarse Fibers High P al39lnrl39r39la a39l r Flairurbr d Somme lm 39Flnlllll Sl 39 r l conveniicnai Fiber Tdmmll EHJin Hidmlmmau Cnmpolill migr fibe i Tensile Sireas Lang Micro bers quot 39 ll HM Imae from Shah and Weiss 1998 5 Temperature Curing UHPC Developing 6 Example SFMKINF P Cement Type I BB 150600 Sand UHPC Advantages Property High UltraHigh Performance Performance Concrete Concrete Min f39c psi 56 days 6000 14000 gt 22000 Min ftpsi about 10 of PC 1350 1750 direct tension Min E ksi 4060 7250 7350 7820 Freezethaw durability 60 80 98 Chloride Permeability 800 3000 18 coulombs Negligible if lt 100 Compression 180 psjpsi Total Shrinkage 180 of drying 400 800 750 but nothing pg inin x 1039 after heat curing Data from Goodspeed et al 1999 amp Graybeal 2005 UHPC Advantages in A T Series 211quot span L71 11 A 7I 12 7 13 7 14 1 7 2 1 5 Imml quot1 121 Lil llidspan de ec un in UHPC Advantages 1 Increase in Girder spans 2 Increasing the spacing between girders 3 Permeability of concrete decreased increased durability UHPC Advantages 4 Offsetting the Long term maintenance costs 5 Minimumizing depth girders UHPC Advantages 6 Further it is predicted that an UltraHPC girder would not require web shear reinforcement except for an amount required to connect the castinplace deck slab to the girder 7580 kgm UHPC Applications 1 Sherbrooke Footbridge 1999 Length 197 ft Deck area 2175 ft2 Volume of RPC 55 yd3 Thickness of the slab 118 in 7 3 a quot i5i m m W iih tll Nitaquot Prestressing 284x105 ksi UHPC Applications 2 Seonyu Footbridge Seoul South Korea 2002 Length 39360 ft Height at midspan ft 4875 ft I39l a 39 Thickness of the slab 120 in Height of the transverse section 427 ft Conventional reinforcement None Prestressing 2646 kips Imaes from Lafarge UHPC Applications 2 Seonyu Footbridge Seoul South Korea 2002 cont Imaes from Lafarge Creep of Concrete Definitions timedependent increase in strain under constant load taking place after the initial strain at loading h I v i timedependent increase in strain under sustained constant load of a concrete sealed specimen Independent of specimen shape and size Contraction Drying creep Basic creep 39lTrzltalI strain Stress induced strain it is the creep occurring in a specimen exosed to the environment and allowed to dry Depends on 390 WWWma speCmen shape and size initial strain Shrinkage Casting time lam fe Mink Strain 99 393 fi strange on start of drying not recorded Swelling Expansr t l Strain is the ratio of the creep strain to the initial strain dimensionless Contraction Drying creep r v it is the creep strain per unit load strainstress Basic creep Stress induced strain Total stram lnitr39ai strain lni af strain Casting time Shrlnfcage lam i I h p ee209s shifters I 39n h p pII Expanlsr ff tg Start of drying Strain before a start of drying not recerded Swelling Creep of UHPC Creep micmstraim J l T 7quot TamlJEI Ed SteanL L L L r Delayed Steam i L Steam 1O Creep of UHPC Compressive Control Stress Initial Elastic Final Creep Cree Specific Curing regime Strength Strain Strain Strain Coef cfent Creep ksi us 08 uspsi Steam curing 90 C amp 95 RH 2727 041 1500 440 029 00390 for 48 h after casting Air AmbientConditions 1653 2 57 1600 m Tempered Steam 60 C amp 95 RH 2565 1670 00980 for 48 h after casting n Delayed Steam 90 C amp 95 RH for 48 h starting after 2442 045 1580 485 031 00440 15 days Data from Graybeal 2005 Compression creep test of UHPC Creep of UHPC Tensile Motivation There is a speci c interest in using UHPC for prestressed high way bridge girders With the UHPC manufacturers recommendation not to use transverse reinforcement the longterm tensile performance of the material should be characterized before specifying it 580 kgm 1230 kgm Imaes from Lafarge and Nawy 2006 11 Creep of UHPC Tensile background Pickett effect 1942 Contraction Drying creep Due to the nonuniformity of the moisture distribution in a drying specimen Basic creep Stress induced sfrain Tofai strain drying creep component was explained by many models by the so called A D MEYi n I microcracking effect gramme 74 3932 ETTTW start of drying not race rded initial strain Shrinkage sag gage initial strain an Swelling Expansi Study of the microcraking problem in tension will be more effective Creep of UHPC Tensile background Kovler 1995 Total Creep Nature of total creep is different than basic creep At the beginning total creep Bash cmquot was less than basic creep Total Creep strain uninf Drying creep component had a negative value initially V shrinkage which decreases 39639 BasicCreep gradually and transforms to I g 39 I pOSitive later I 39 tags u ner nadlin3sl 95 ME 121 Creep of UHPC Tensile background Kovler 1995 edc Ssc ecs Where ecs is creepinduced shrinkae dominating at the beginning always ve E E l 3 E 753 Ian 421 m esc is shrinkageinduced cree dominating at the later stage same as basic creep Creep of UHPC TenSi le baCkg mquot T reffr firI pf Abnormal behavior I Kovleil 1999 I It was found difficult to apply the previous approach to experimental data Tensile loading and drying produce strains of different directions These two components will change with time Total Creep Basic Creep Total Creep Basic Creep 12 34 i rm 3930 7 3 el 95 39IIUEIB 13 time under lead ileum D u S E Total strain M aw Hm X s Strain nr ansmmnj39 J Free shrinkage g m U l 2 3 41 5 B l DWIle of lama arer 300 r I 250 W A Total stra1n T Basic creep f A k AL 1 a A a a E A G 1 2 3 4 5 6 7 Dulzrmm 0139ch Wrong M D c up I Q J Strain mfrmsrrain U39l D m r y G 13 Creep of UHPC sealingx 7 quotquotL39 I idisplacemant of capillary wall 39 swelling The excess basic creep strain over total creep was attributed to swelling of the sealed specimens removal of free water changing of meniscus radius no displacementriftirlpillargI wall m1 shrinkage f sealing a evaporation of water In the 3quot capillaries under 100 RH 2 E i no shrinkage displacement of capillary wall I i i 394 i swelling b39 evaporation continues and R changingofmeniscumdius reduces to r shrinkage c swelling starts with sealing as the minsucs becomes flatter Creep of UHPC A D D h m 0 Total strain Basic creep bc 8sw 398 8 bcc0rr 1 7x E E E e 2 150 2 150 5 38 5 E 53 E 53 63 k frt r rk pm kA r a H km n H h a A quotin D 3 4 Duration oflmd days Duraiiun afloat drills 4 IHo o g Drying creep of concrete under tension actually represents creep strain not sh nkage Creep of UHPC Tensile Background Due to the significant difference in the watertocement ratios between both the cases 07 in the case of this study vs lt 02 in case of UHPC results that could be obtained from similar tests on UHPC might be significantly different than what was obtained in the previous study Creep of UHPC Tensile Test Setups 1 Kovler 1994 0 Advantages 1high resolution 512 reading sec 2completely automated setup o Disadvantages 1compensation cycles may cause premature failure if the load strength is high 2limited number of specimens 3 possible load eccentricity 15 Creep of UHPC Tensile Test Setups 2 Bissonnette and Pieon 1995 0 Advantages 1 Relatively simpler 2 Constant centric loading is anchoredsteerulme guaranteed throughout the test mm 5433601700 mm quot a Disadvantages 3 i 39 1 Top and bottom specimen connections design especially for high strength concrete hinge l applications quotin 71539 r39evlaining spring 2 Manual loading may cause leveramw disturbance 3limited number of specimens xed frame i front ru El 7 Strain gage quot amplifica on lactor 41 quotE hinged frame 16 Creep of UHPC 1 quotSteady load application 2ability to test 3 replicates frame 1 the strain gage electrical properties change with time I Load and thus make it unsuitable for Ci 5 regulator 800 kP long term testing 2 39 0 a 2 loading is not constant allover T 539 Iv Iw130mm Detail 11 Detail I i 5 Detail 111 i 8quotx18quotx1 Creep of UHPC w Tensile Test Setups Test Setup Features Loading Axial and constant loading throughout the test Load capacity of 16000 lb 1780 psi on a 3x3 in specimens Strain measurements using mechanical dial gages accuracy of 00001 inch Specimens 6 frames will be built total of 18 3x3x15 in specimens can be tested at the same time Designing the specimenend plates connection Creep of UHPC Tensile Key Results 1 Use of Silica fume as SCM glowed ail 1d g u umm ail Id quotinhuman 51de hnnIaadad aim gpexcilzc creep IEMWMMEPE Speci c creep unv39wMPai 3 Elm Em MPai GT5 an in Time since leading in Time strut3 loading m Data from Bissonnette and Pigeon 1995 tensile creep Creep of UHPC w Tensile Key Results 2 Use of steel fibers iiirniMF39a Specific creep p H i355 genital iitiC wl Time since Heading til Data from Bissonnette and Pigeon 1995 tensile creep Creep of UHPC Tensile Key Results 3 Stress strength ratio nulnsecied ai39i 39 i E1i id aird an Spamin creep Epi i ii mMF ai 31 d g m HIEEl Tm tinti MPH I ii I I i I I I 39 Ii ll r l 2 iii 4D Time slime loading Eli Imae from Bissonnette and Pigeon 1995 tensile creep Creep of UHPC Tensile Key Results Results Altoubat and Lange 2001 Effect of fibers oThe incorporation of fibers in the wet condition decreased the initial basic creep as they controlled microcracking Under drying conditions these previously effects of using fibers are not evident likely because under these conditions more surface microcracking occurs Effect of wcm The tensile basic creep increased upon decreasing the wcm This may suggest that the tensile creep behavior at early age is governed by different factors than in mature concrete Concluding Remarks 1There is a need to improve the fundamental understanding of the tensile creep behavior of steelfiber reinforced ultrahigh cementitious matrices Characterizing the the longterm tensile behavior of UHPC reinforced with steel fibers and will assess the efficiency of specifying it for use in highway bridge girders without transverse bar reinforcement 20 THANK YOU Questions 21 Curling ofConcrele Pavement Quintin Watkins CEE 8 813 Spring 2007 Outline 0 Cause 0 Analysis 0 Research Project 0 Conclusion 4182007 Curling Cause 9 Temperature Curling QMOisture Warping Q Shrinkage O Creep Temperature Gradient Curling Subbase or Subbase or Subgrade 1 Temp al mp gt Temp at hollom b Temp m up lt Tl39mp at bollom daytime tuiglnlimu Ref CeylanH et a1 2007 4182007 Construction Temperature E eets PCC Slab a Temp 11 top gt Tlllllt lil bottom It Tlmpl lll lop Temp al bullonl during telling limo Infill lllling liml39i Ref CeylanH et a1 2007 Temperature Pro le of Slab Temperaturepro le through the depth ofPCC is nonlinear V U Tum nonlinear a liniform it Liucnr c anientnnicnl lulllllcrallll o profile component cmupuuulll nonlinear compnuuul Ref Ceylan H etal 2007 4182007 Moisture Gradient Warping A Subbase or Subbase or Subgrade Subgrade la Moislurc m lop gt moislurl a hollow 1 Moisture al mp lt moiuuru m bullom Ref CeylanH et a1 2007 Slab Moisture Content PAVEMENT 10 m 25 40cm 139 1 l 1 F Iquotquotl 50 El 70 80 90 100 110 AVERAGE MOISTURE CONTENT Per cent Ref Carrier R E et a1 1975 4182007 0 Early Age QChemical Shrinkage QAutogeneous oPlastic OHardened Concrete Drying Shrinkage Pavement Drying and Wetting Negulive mam x we Ref Mmdcss c1 1 1003 Behavior Tme days 10 4182007 Creep m 2 Timu0 llIiTimcw hf cm a 1 20m Shrinkage and Creep Effect 41 32007 OWestergaard 1926 OCurling Prediction Theory using Dense Liquid Foundation OBradbury 1938 ORefined Theory to Slabs of Finite Dimensions Analysis 9 Finite Element Analysis 1940 s FE Finite Element Programs l m In our rim pu u 111 61M mmm K ISl Mi mgram 2mm our lQll k1511 ll UNS lll lmll 2 11 lnl mmlel 1 quotmamm umu pm 21 medium mrcu plmc r mamm umu plalc plenum and mm mm spring hmm tlcmnnt on Splluu limudmmn r incur spnng mm 1 ltprlng limudmmn r incur Wing l n rorsmna r mr mu 1 spluig rum and imnllncnr mm m rlcnunts gap cicmmm mullmnnu c msuuun npliun quotmum l numluuon modults Dam llqlml m IMramclc mom 1 a Dem iqui Dense mm mm llqmll imam dn Imnl mml39 spr mg Dam Ilqlml Rclcrcnuc luhruulxrur c1 al N73 lxlmmnm I511 rI low or rmlm er m 195 L hull WXI Huang too 1m n 3911 1 1X7 Um in or M l MK ion Alum s mrprm m our rim NNYS Zl hcll clrmcm clcmml 3D buck rlnmrm Ref CeylanH et a1 2007 l incur and nonlmcm sp ACE u n gap mm mnlnpnnn nsnninl mum vdcls r um um urmlmcru ring mm rm mm Mm i moms mullmnrm co rricplcn mmlch Dense mm 31 In Ick clement musnmth c umdcls usel ilcl39mcrl mmlclx Dcin mum lxuo rl ml NUS Museum or al 109639 lxim C1ll Jon nldiquc loin ruhlmh a M JHUJ 4182007 Finite ElemenlAnabsz39s Inputs 0 Subgrade Prope ies OMaIerial Prope ies OMesh Dimensions Subgrade Model Winkler Dense Liquid Model H Kmth 4182007 4182007 Factors A ecting Material Properties mamas nrrEanG Momma U n asvvcxrv o CONCHK39E mum 7 Variouspsrmncluramzun ucncclhemndulusulclasucnuicunurclc Finite Element Output 9 Pavement Response QJOint Load Transfer ODynamic Load QEnvironmental Load Research Studies on Airport PC C Pavement 9 Denver International Airport 1990 s 9 FAA s National Airport Pavement Test Facility early 2000 O HartsfieldJackson Atlanta International Airport 2006 Atlanta Pavement Project Objectives 9 Measure slab curling and possible slabbase separation in the eld 9 Determine if slab curling is signi cant factor for thick slabs 9 Determine different responses due to loaded and unloaded slabs 9 Determine slab responses for different edge conditions 4182007 Atlanta Pavement Project 0 Three PCC slabs were instrumented during the recently completed reconstruction of Runway 8R 26L and part of parallel TaXiway E at Atlanta Harts eldJackson International Airport 0 Site selected is at the eastern end of TaXiway E O Sensors were installed Oct 1618 2006 Concrete was placed Oct 18 0 Initial data acquired manually A permanent data acquisition system was installed in Marc 4182007 Atlanta Slabs Location Hz 3 ll l n mun 1 a 1 Guam X 5 ONC SLAB FOR FAA ENCLOSURE 1 1 1 1 I ECONDARY TMl ROUTE Sensors Installed 0 Vertical Displacement Transducers VDT ed at center and edge ofs abs 0 Concrete Strain Gages SG 0 Installed at multiple depths in center and edge of slabs o Depths of14 10 and 19 inches 0 Temperature Sensors T 0 Installed in two slabs 9 Depths of05152560100140 and 190 inches 4182007 4182007 VD39M VDT2 SIM392 W74 VETD SG22 VD39Mt SLAB 1 SLAB 2 5w vma 3 mm I m W12 55 I m WW 5 2021 a 7m warG vow 5W2 Von vuw vow SG13 vows mm mm SLAB 3 swamwas we o we 55211291 mm 25m vatw mm mm 1 Scmm39 LAW in mm B Inslmnmucd Mam Atlanta Sensor Installation Data Collection 0 EarlyAge Responses 9 Collected manually every hour for the first 48 hours after PCC placement to capture earlyage responses 0 Hardened Concrete Responses 9 Collected manually twice daily between Oct 31 and Nov 6 O Collected manually twice daily between Dec 5 and 8 9 Continuous hour readings will start Mar 22 Temperature deg F deg c Slab 2 Free Edge De ection Response with Temperature De ectinn mus 1mm tenses wanvs lOZEDG MD06 110405 woeus no 00 no 00 no no no 00 00 DO 00 no on no 00 Dexemme Te2A r72lt3 NW3 Temp DT43 l39igurc 7 I m ul39VlHel Response ill Icnmn nun r Ref BdllD R et a1 2007 23 4182007 Slab 3 Dowelea Joint De ection Response with Temperature Temperature ag 1ng c De eamn mus 1mm mWue 102005 mas06 103005 1 HIM16 was05 00 00 00 00 00 00 00 00 00 00 00 00 00 0000 m 00 an Dalc39vaa T72A TZG NW5 Temp 39 VDT G Iignu x quot01ul39VlIrlhkc pulhcMm lcmpumlm39u Ref BdllD R et a1 2007 29 Slab I Center Slab SG Readings with Temperature Oct 3 I Nov 5 Strain mmrnstram Temperature deg F 40 103H2006 1002005 mzxzoos MSZODG MIA2006 His2006 2005 200 AM Daemme 12 126 SGVS 576 3910an 01101 505 0nd vr RL splmsca will lunpclulm c Out 31 r m 5 Ref Balm R et a1 2007 30 4182007 Concrete Biodeterioration CEE 8813 April 25 2006 Jonah Kurth Lecture Overview 5 History of Research Types of Microbes Methods of Deterioration Methods of Remediation History of Research Degredation of sewers first detected in 1900 Original explanation was purely chemical Australian research in 1945 rst to correlate bacteria and deterioration 9 Gu JD et al 1998 Slide 3 squirm Early Australian Resear h First to link bacteria to deterioration Showed that Thiobacili concretivorus not H28 caused most deterioration Proposed multiple species are responsible for deterioration Fig 1 Blocks after removal of corroded material lnm umlml tit4619 Rtrniu D 18 Parker CD 1945 Slide 4 Research in Germany H Identified three strains in Hamburg sewer T intermediusnovellus colonizer T neapolitanus pH lowerer T thiooxidans destroyer Performed experiment before demolition Turned on oxygen supply pH increased T Thiooxidans diminished 16Mildellt etal 1983 Current Research Fungi considered for biodeterioration 91331 Nitrifying bacteria discovered on building exteriorsl23ivl221 No longer con nes research to sewers Concrete parallels stone and wood deterioration Use of modern techniques to study microbes SEM LVSEM to photograph stains l5 pCR analysis to identify species 271 Types of Microbes i Sllde 7 39frv Sewer Microbes Environment Anaerobic oxygen poor Low light conditions Sulfur Rich nxagsgo so2 1x 0 e 2Nn15 06 rim smg Type of Deterioration 2Nu a u10402 v so unrso second stng Dissolves cement compounds Fig 1 Metabolic reactions of Reduces reinforcing cover Thwbac m Reduces section thickness leading to collapse 19 Parker amp Prlsk 1953 Slide 8 r A Atmospheric Microbes Environment Local site characteristics Intensity of light exposure Prevailing wind direction Speci c moisture conditions MineralPhysicalChemical conditions ofthe sur ce Global site characteristics General climate N America vs Europe etc Humidity and elevation Ocean vs Inland speci cally salt content 31 Atmospheric Microbes Environment TypesofOrganisms Cyanobac i Major contributor to bio lm color Can growin high UV lo moisture Usually dominant biomass on concrete El Fungi Major contributor to physical biodeten39oration May work symbiotically with bacteria 91 Algae Highly dependent on water content porosity Traps water through bio lm sheets Slide 10 Fig 3 LVSEM nutmgnph black min i x imn Fig 5 SEM mlcrugnph gru n tum ry mum 5 Dubosc A et al 2001 Slide M v39xf Atmospheric Microbes 39 Environment Types of Organisms What do they do Microbes are not beni n Cause premature weathering through Chemical attack 30 of weathering is biological 31 Slide 12 Chemical Attack Reactants for natural metabolism Minerals solubolize metabolites Enzymes break down mortar Utilize ions present in cement d by Fig 5 Dcmchml ylntcs renew where calcium afa summed hxuliw mica from carbonate appeared also la be mluhiliwd Pholumiummph by Rmus sum 8 Gaylarde C C et al 2003 Slide 13 Chemical Attack 2 Reactants for natural metabolism Products of natural metabolism Nitric and organic acids Release polyols glycerols disrupting silica 0 me in grams of calcium carbonate FigVGA s u i7ed v phntamcmgmph by 1mm saw 8 Gaylarde c c et al 2003 Slide 14 pmmy m 39F39quot quot39quotquot Fig 5 Scanning cimmn mlcrmmpy image ohlie mpcrliclal Inycr nf me mucrmc mm immmi chntmml gypmm m muau ruwl Chart of porosity v5 depth a erexposure to bacteria 1 vuihla m l39lnc smmurcs 3r premmxbly he dried mmm ohm bm lm 3 DeGraef B etal 2005 Slide 15 Filamentous growths Can be from fungi cyanobacteria algae Physically pry away com onents Filaments are lt10 pm x V Fig1 Fungal mm in m immode cnncmc Ufa pier ofn biidgc quotrimmed m polluted river pmmmmph by Rim sum 8 Gaylarde c c elal 2003 Sllde l5 Passive Physical Attack Biofilms and slime Discoloration Colonizer enables other growth Temperature changes thermal behavior Hydrophilic traps moisture 1 Kurt71 2007 Nurth Ave Underpass 25 Warscheid T amp Krumbein W E 1994 Slide 17 T Mitigating Growth in Active measures Photocatalysts Biocides Passive Measures Cement properties Reducing favorable conditions Slide 18 Biocides Paints and Coatings Cover exposed surface with biocidal coating Chemically disrupt cell grow Limited effectiveness as time increases Increase resistance to biocide by microbes Disinfection and washing Soaked with hypochlorite bleach and pressure washed t No postapplication biocidal effec s 23 Shirakawa M A et al 2004 Slide 19 Biocides 2 CuFl1Wn CUFl cm 20 an a 11m mom Fig 1 Fig warm 23 Shirakawa M A et ai 2004 Slide 20 Light energy causes a catalytic reaction to break down cells momma 9mm Pulml ysk RE 5 Algae gmwm lnr varlnns phnlocalalysls nmmallzed In an unpmlacled cement subsuale mlxed lamp lnanlaunn Possible catalysts Metal Oxides TiO2 and vvo3 mu with noble metal cocatalysts Pt amp lr7 l5 Llnkous CA et al 2000 Slide 21 Importance of structure and dispersion Only anatase is photocatalytic Mixing with cement is not a ef cient but still effective Commercially available product TX Active TX Aria Portland cement mixed with u 5 1 0 is u Irrmtiuliun mun 2 3x as expensive as regular cement 21 Rachel A et al 2002 Slide 22 Applying Expensive Cement 9 TiO2 layer shows no increase in effectiveness beyond 12quot 1 Existing practice fills esquot surface blemishes with cemen Material costs are only a fraction of total cost Christopher Eagon Essroc personal communication Slide 23 April 2007 Reduce favorable cond Environmental Reduce exposure to rain Reduce airborne pollutants and nitrates Keep birds away from structure Construction Practices Clean form releases from concrete Smooth surfaces to reduce roughness Slide 24 Changing Cement Properties Polymers Reduce permeability of concrete to acid infiltration Enable concrete to bridge microcracks Some polymers work others do not Silica Fume and SCMS Reduce porosity and moisture retention Silica fume shown to inhibit growth 51 Silica fume also shows reduced resistance to acid attack 24 Increase wlc ratio Decrease permeability increase paste density 5 MDOT study shows growth occurs mainly on paste 01 Slide 25 Favorable Conditions Example Slide 26 Natural Fiber Reinforced oncrete Ben Davis 422007 Overview Fiber reinforced concrete Types ofnatural bers History ofnatural FRC Wood pulp ber composition and processing Wood pulp FRC 7 Fresh properties 7 Mechanical properties 7 Durability Future research and conclusions Fiber Reinforced Concrete Factors controrrrng perrorrnance or composrres qmred c usery spaced rermurcmg bars n nuuus e SmaH rermurcemem ratm when compared m rermurcemem bars Area umermurcemem Area m Concrete Remmrcemem 39auuz m ma Fiber Reinforced Concrete Advantages Disadvantages e Easrry praced e Emcrency factors Cas1 as ow as 4 VD Sprayed Spray pracernem Lessrabuvmtenswe method or 25 37D than pracmg rebar pracernem casmg 7 Can be made rmo emod Wm sheets or 7 Not mghry effecuve rrregurar shapes r rmprovmg 7 Used when pracrng compresswe rebar rs drrrrcurr gt mum Comparison of Fiber Types and Properties mum E ks xm m mm Types ofNatural Fibers s samcmmm mum s gmwgmmm Mew mam cawmammas WWW W m Mexma Awdumb ua mum mm muses quotmamas mm a cancmn Mun a quotwadesh Dun mmm masesmsue exumandcam resswesven hs as weHas exumhauvhness V a E epham evassmaw nmaaS m amka andmanda kahmssuneeaswe as WW amnsmn mm ncmases exurahnd mvanmnmh Egyptians used straw in making mud bricks 120014 OBC Exodus 6 2500 BC asbestos bers used in Finland to make clay pots Active Asbestos I o m a 939 2 nl 50 m 390 m 38 3 m 3 E mwwwmrgummwnmw wigsumm a 2 mm Current Uses waer Cement Boardr James Hardwe 7 5mm 7 Backerbuard 7 Run ngmatena s 7 Nun pressure mm BuckeyeTecnno ogwes 7 Unranbersuu Cam s zuu James Heme BMEKEVE Yemna agxes Wood Pulp Fiber Composition 21 Hardwoods 25 Softwoods Terpenes Resin Acids Softwoods Fatty Acids enols Unsaponi a bles CARBOHYDRATES 35 Hardwoods 25 Softwo ods CELLULOSE HEMICELLULOSE Glucose Mannose Galactose Naik 2003 m fase 9 Wood Pulp Fiber Composrtlon Cellulose CeH1205 n degree of polymerization 6001 500 for commercial wood pulps Determines the character ofthe ber As cellulose increases fbertensile strength and E increase linearly Hemicelluloses polysaccharides of five different sugars Easierto degrade than cellulose Highly variable with bertype Lignin complex polymer composmon Bindswood together Found in the middle lamella Used in concrete as a set retarder Extractives ML middle lamella No physical structure P primary wall tgigtee properties such as color odor s secondary wall Some can be incompatible with 39 39 lumen concrete TAPPI Young 10 Wood Pulping Process Mechanical Pulping Chemical Pulpin Ev mechanicai eneiw Smaii amuum Ev chemicais and heai Mme ur nichemicaisandheao numechamcaienamv ViEid a ViEid 6 55 sham weak umaaie imPUYE bers Lunar s1mnu s1aaieuaevs Gum pm uuamv mm mm uuamv s1u euruunwmk k iaimE re nermechamcaipuip smmeltaumc 2c amcaipuip suda V ammmnbvmassmnmn 25 31 Humnbv mass Mom dueiuupeniumen s dueiucuiiapsediumen ieid WeighiuipuipWaium m mm mm MW mm mm wendN u Fresh Properties Workability Settingtime Cement hydration Fiber clumpingconsolidation Shrinkage r iastic a Dying Internal curing and autogenous shrinkage Workability Addition of fibers decreases workability mm W mm my use of sum Nor n due to an increase In surface area Low fiber fractions lt1 by mass can significantly reduce L s ump Eggzziizzw musgm Control 925quot m i we swam wc47 E 8 by mass fibers 256quot wc47 ASTM C995 better indicator for workability than slump for FRC ASTM C995 placed by vibration Time of flow 815 sec recommended for FRC Naik 2004 Slurry Dewatering Process Used in high fiber fractions normally fiber cement board 9 by mass Initially high water content is produced to achieve high fiber content and uniform distribution Hatschek machine shown below Kuder 2003 Com eyor Belt Accumulator Roll Bins containing dilute slurry Setting Time Boollnitiel 39 mini o can be used as a Ewan PUID Softwood Krall DHEFGWOOU Krali set retarder Fibers with Iignin or other chemicals can have adverse effects on set time Fibers may 0 F i C 39 roar Mass onxen as absorbdesorb water from Final Se mm the cement matrix or atmosphere effecting set 0 Eugen Pulp smtwood Kral39l DHBFGWOOO Kmri time Mechanical pulped fibers 25 31lignin Chemical pulped fibers 0 8 Iignin O H 1 2 Naik 2003 Soroushian 1990 PM Me quot Equot Wquot Soroushian 1990 15 Cement Hydration Addition of fibers has little to no effect on cement hydration g nvbrol d P d Contro o oo ow er Wood Powder 3I TMP Film 250 e 3 TMP Fiber 3 13 Kraft Fiber 3 Kraft Fiber Control 3 Kraft 3 Kraft Fiber 3 TMP Fiber 3 Wood Powder 3 Wood Powder Normalized Cumulative Heat Evolved J a O 3 TMP Fiber Power Evolved mWIg cement i V 0 12 24 36 48 0 12 24 36 48 Time after water addition hr Time after water addition hr Mohr 2005 Fiber ClumpingConsolidation Pulp fibers have the tendency to clump together in water If fiber clumps are included in concrete they turn into weak spots in the concrete Research on mill residuals suggest that there is a direct relationship between ease of repulping and durability of the fibers Possible chemical coating of fibers to increase separation Chun 2004 Plastic Shrinkage Occurs due to the loss of water at the surface faster than bleed water becomes available Concrete is too stiff to flow but not strong enough in tension to resist cracking Kurtis 2007 Addition of fibers can reduce plastic shrinkage cracking Stops the spread of microcracks Increases the tensile stren th of concrete Sorous ian 1991 Fiber Microcrack Plastic Shrinkage Cellulose bers reduce plastic shrinkage in both normal and high performance concrete Soroushian 1998 Polypropylene fibers normally used for crack resistance pulp fibers could be more economical due to their low costs even if higher fractions are required 8 8 Crack Area mm 2 B S Conventional Conventional HPC HPC 0 0 00 060 0 06 Soroushian 1998 Volume Fractions Other Types of Shrinkage crack 1 Free shrinkage pulp is 030 hygroscopic and releases water upon drying could account for dimensional change of the composite Sarigaphuti39s research suggest no effect Restrained drying PLAIN 0 a o I 0 a O I 0 N o I 10 20 30 40 TIME DAYS shrinkage due to restraining and minimization of evaporation bers can delay onset of cracking and 040 reduce crack size 020 crack 2 Rapoport 2005 39 Warn 0 LONG SW SSK CRACK WIDTH mm 1o 20 30 40 TIME DAYS Sarigaphuti 1993 Internal Curing and Autogenous Shrinkage Mechanically pulped fibers minimize autogenous shrinkage even better than super absorbent polymers Chemically pulped Kraft fibers have minimal effects on autogenous shnnkage TMP fibers have detrimental consequences to compressive strength Mohr 2005 us Deformation microstra n D E 4200 51 1600 01 1 Time days 10 100 Contro 025 SAP 050 SAP 075 SAP 100 SAP 0 E 1200 51 2 lt 1600 01 1 Time days 10 100 Control I 075 TMP 0 150 TMP 225 TMP ii300 TMP Mechanical Properties Compressive strength Flexural strength Flexural toughness Impact strength 22 11 Compressive Strength High fiber content composites can have reduced compressive strengths Strength reduction most likely due to increased amount of entrapped air due to presence of fibers Most research agrees that volume fractions up to about 1 does not significantly effect compressive strength Compressive Strengm MP6 lUU W Mam Pulp Sollwoou Kmli El Hardwood Kvsll 1 Fiber Mass Content 13 Soroushian 1990 23 Flexural Strength In general as fiber content increases so does flexural first crack and peak strength Influenced by moisture content of the composite Research disagrees on the optimum fiber content for peak strength Varies between 6 to 20 by mass Mohr 2005 Load KN 4 1 Kraft Fiber O 005 01 015 02 025 Deflection mm F iiii rel strength MPa Soroushian 1990 any Mass comm m 24 12 Flexural Toughness Toughness is de ned as the amount of energy required to break a material area under the load meuml Toughness Nmm wu deformation curve Mehta 2006 Addition of pulp bers in concrete B 39 increases flexural toughness Normally toughness after rst crack is compared No clear method for measuring can be very test specific 2 Japanese code JCISF ASTM C1018 New method EIAshkar 2006 Identify rst crack point Unreinforced toughness subtracted Use of indexes to describe the postcracking portion of the load de ection curve B Macn Pulp soiiwnoa mu Dnarnwaun mu 0039 l Fiber Mass Content as Soroushian 1990 Impact Strength Nor Number of blows by a standard weight to crack or fail the composite 5 quot Impact strength for fiber reinforced slabs is 318 times higher than plain mortar slabs Residual impact strength Irs 137 for non reinforced cement and up to 391 for FRC Energy absorbed at ultimate failure Energy absorbed at initiation of firstcrack LL aAsz ugx rs Soroushian 1990 of Etows Emmi Pulp Softwood Krall Elnamwoun Kurt O l 2 FIDB Mess Conisnr 1 is 5 mm 21 HARDENED STEEL BALL Non was m agwaaw BALL AND we 2391239 STEEL PIPE 1 BAR 2 x V em 2 x I x Mix 022 ll Ramakrishna 2005 A0217C 13 Durability Wetdry exposure Fiber failure modes Freeze thaw resistance Permeability Durability improvements WetDry Exposure After 25 wetdry c cles on unmodified pu p fiber composites Mohr 2005 4352 loss of first crack strength Load kN 5172 loss Of peak a 025 050 075 100 125 Strength Mohr 2005 Deflectionlmm 97 99 loss of post 3 cracking toughness E Plain 37 um LSWSSK Other research a 20 a 0 V 39 1 suggests only a 40 o a n loss In flexural L13 a toughness and an g m Increase In flexural 3 Strength Sarigaphuti 1993 Soroushian 1994 00 o 5101520253035 40 Sarigaphuti 1993 CVCIGS 28 WetDry Failure Modes SEM micrograph of 0 cycles fiber pullout method of failure SEM micrograph of 25 cycles fiberfracture method of failure Mohr 2005 Ductile failure at 0 cycles of wetdry Fiber pullout Necking on fracture Brittle failure at 25 wetdry cycles Due to the mineralization of the fibers Mohr 2005 15 Freeze Thaw Resistance Fiber cement board and the effects of pressure treatment 9 cellulose fibers by mass Cellulose fibers increase freeze thaw durability 52 ICC Evaluation 4 v n o m Flexural strenglh MPa 3 l l u Kuder 2003 Frame bur Permeability Fibers reduce permeability of unstressed concrete Reduction is 39 to volume fraction Normal concrete permeability increases at 3 X fc u rum Fiber 2 01 mm 03quotquot Film 7 x 05 ber Increases in permeability are minimal until 5 X fc for Fibers are expected to increase overall durability due to decreased permeability Banthla 2007 Nurmaliud nmeabiliuy Coefficient x 10 511235 ml m Banthla 2007 Durability Improvement Pressure treatment on ber cement board Reduction in wlc ratio to decrease porosity Addition ofSCMs eliminated degradation due to wetJdry cycles Mam ms 7 30 50 Silica Fume e 90 Slag r 30 Metakaoiin 235 r 10 SF70 8L 7 10 MK23570 8L 7 10 MK23510 SF70 8L Chemically coated bers Conclusions Natural bers offer many bene ts for reinforcement 7 LOW cost and abundant 7 Renewable 7 Non nazardous 7 replacement or asbestos Can improve characteristics of concrete 7 increase fiexurai strengtn and tougnness resistance 7 Reduce shrinkage and cr ckn 7 improve durability by stabilization or microcracks and decrease in permeability Future Research Sources of pulp bers Thermomechanical b rs Paper mill residual solids Optimal ber ratios for speci c uses Durability Additional research on 39eeze thaw SCM addition References Active Asbestos Management Limited Asbestos History Retrieved March 26 2007 from http www active asbestos co uldframeicentreiaboutihistory html AC 217 C Acceptance Criteria for Concrete with Virgin Cellulose Fibers ICC EVALUATION SERVICE Inc Whitter CA 2003 ASTM C 995 Standard Test Method for Time of Flow of FiberReinforced Concrete Through Inverted Slump Cone American Society for Testing and Materials West Conshohocken PA 2001 Balaguru P 1985 Alternative reinforcing materials for less developed countries International Journal for Development Technology V 3 87 107 Balaguru P 1994 Contribution of bers to crack reduction of cement composites during the initial and nal setting period ACIMaterials Journal V 91 No 3 MayJune 280288 Banthia N amp Bhargava A 2007 Permeability of stressed concrete and role of ber reinforcement AC Materials Journal V 104 No 1 JanuaryFebruary 7076 Buckeye Technologies Inc UltraFiber500 Retrieved March 27 2007 from httpwwwbkitechcom Castro J amp Naaman N E 1981 Cement mortar reinforced with natural bers AC Materials Journal V 78 JanuaryFebruary 6978 Chun Y 2002 Investigation on the use of pulp and paper mill residual solids in producing durable concrete Unpublished masters thesis University of Wisconsin Milwaukee Milwaukee WI Chun Y amp Naik T R 2004 Repulping brous residuals from pulp and paper mills for recycling in concrete TAPPI Journal V 3 No 12 December 712 Chun Y amp Naik T R 2005 Concrete with paper industry brous residuals miX proportioning ACIMaterials Journal V 120 No 4 July August 237243 Coutts R S P 2005 A review of Australian research into natural bre cement composites Cement amp Concrete Composites 27 518526 Design and control of concrete mixtures 143911 ed 2006 Skokie IL Portland Cement Association ElAshkar NH amp Kurtis K E 2006 A new simple practical method to characterize toughness of fiberreinforced cementbased composites AC Materials Journal V 103 No l JanuaryLFebruary 3344 Fiber reinforced concrete 1991 Skokie IL Portland Cement Association Ghavami K 2005 Bamboo as reinforcement in structural concrete elements Cement amp Concrete Composites 27 637649 How much paper can be maalefrom a tree 2001 Atlanta GA TAPPI ICC Evaluation Service 2005 ES ReportiBuckeye Technologies Retrieved March 27 2007 from httpwwwbkitechcom James Hardie International Products Retrieved March 27 2007 from httpwwwjameshardiecom Kurtis KE 2007 CEE 8813 Materials Science of Concrete lthttpwwwcegatech edu7Ekkurtisconcretehtml gt accessed March 2007 Kuder K G amp Shah S P 2003 Effects of pressure on resistance to freezing and thawing of fiberreinforced cement board AC Materials Journal V 100 No 6 November December 463468 Mehta P K amp Monteiro J M 2006 Concrete microstructure properties and materials 3rd ed New York McGrawHill Mohr B J 2005 Durability ofPulp Fiber Cement Composites PhD thesis Georgia Institute of Technology Atlanta GA Naik TR Chun Y amp Friberg T S 2004 Use of pulp and paper mill residual solids in production of cellucrete Cement and Concrete Research 34 1229 1234 Naik TR Chun Y amp Kraus RN 2003 Use of residual solids from pulp and paper mills for enhancing strength and durability of readymixed concrete Final scienti ctechnical repo submitted to the US Depaitment of Energy for Project DEFC07OOID13867 Ramakrishna G amp Sundararajan T 2005 Impact strength of a few natural fibre reinforced cement mortar slabs a comparative study Cement amp Concrete Composites 27 547 553 Rapoport J R amp Surendra S P 2005 Castinplace cellulose fiberreinforced cement paste mortar and concrete AC Materials Journal V 102 No 5 September October 299306 Rodrigues C S Ghavami K amp Stroeven P 2006 Porosity and water permeability of rice husk ashblended cement composites reinforced with bamboo pulp Journal of Material Science V 41 No 21 69256937
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