AMCM 2011 Presentation for "Numerical analysis of early-age thermal and moisture effects in RC wall"
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AMCM 2011 Presentation for "Numerical analysis of early-age thermal and moisture effects in RC wall"

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Presentation for the paper on AMCM 2011 Conference, Cracow, Poland. Full text available:......

Presentation for the paper on AMCM 2011 Conference, Cracow, Poland. Full text available: https://www.researchgate.net/publication/236171560_Numerical_analysis_of_early-age_thermal_and_moisture_effects_in_RC_wall?ev=prf_pub

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  • 1. Numerical analysis of early-agethermal and moisture eects in RC wallDSc. Eng. Barbara KLEMCZAKMSc. Eng. Agnieszka KNOPPIKWRÓBELSilesian University of TechnologyFaculty of Civil EngineeringCracow, 14 June 2011
  • 2. IntroductionNumerical modelAnalysis of RC wallConclusionsIntroductionconcrete curingcement hydration processdissipation of heat and migration of moisturetemperature and moisture gradientsstressesself-induced, restraint stresses in structureBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 3. IntroductionNumerical modelAnalysis of RC wallConclusionsIntroductionthermalmoisture inuencesmassive structuresfoundationsgravity damsmedium-thick restrained structuresRC walls of tanks, abutments, castagainst old foundationBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 4. IntroductionNumerical modelAnalysis of RC wallConclusionsThermal and moisture analysisThermalshrinkage strainsStress analysisImplementationGeneral assumptions1 phenomenological modeldecoupling of thermalmoisture and mechanical eldsfull coupling of thermalmoisture elds2 stress state determined under the assumption thatthermalmoisture strains have distort character3 viscoelastoviscoplastic material model of concreteBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 5. IntroductionNumerical modelAnalysis of RC wallConclusionsThermal and moisture analysisThermalshrinkage strainsStress analysisImplementationThermal and moisture analysisCoupled thermalmoisture equations˙T = div(αTT gradT + αTW gradc) +1cbρqv˙c = div(αWW gradc + αWT gradT) − KqvInitial conditionsT(xi, t = 0) = Tp(xi, 0)c(xi, t = 0) = cp(xi, 0)Boundary conditionsnT(αTT gradT + αTW gradc) + ˜q = 0nT(αWW gradc + αWT gradT) + ˜η = 0Barbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 6. IntroductionNumerical modelAnalysis of RC wallConclusionsThermal and moisture analysisThermalshrinkage strainsStress analysisImplementationThermalshrinkage strainsImposed thermalshrinkage strains εn:volumetric strainsdεn = dεnx dεny dεnz 0 0 0calculated based on predetermined temperature and humiditydεnx = dεny = dεnz = αT dT + αW dWBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 7. IntroductionNumerical modelAnalysis of RC wallConclusionsThermal and moisture analysisThermalshrinkage strainsStress analysisImplementationStress analysisviscoelastic area˙σ = Dve( ˙ε − ˙εn − ˙εc)viscoelastoviscoplastic area˙σ = Dve ( ˙ε − ˙εn − ˙εc − ˙εvp)Figure 1: Failure surfacepossibility of crack occurrencesl =τoctτfoctFigure 2: Eort levelBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 8. IntroductionNumerical modelAnalysis of RC wallConclusionsThermal and moisture analysisThermalshrinkage strainsStress analysisImplementationImplementationA set of programs:TEMWILthermalmoisture eldsMAFEMstress analysisBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 9. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyInput dataconcrete class C25/30, steel class RB400cement type CEM I 32.5R, 450 kg/m3,temp.: ambient Tz = 25◦C, initial of concrete Tp = 25◦C,wooden formwork of 1.8 mm plywood, no insulation, noprotection of top surface; removed in 3 days (72h).Figure 3: Geometry and nite element mesh of analysed wallBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 10. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyThermal and moisture analysisFigure 4: Temperature distribution in the wall [◦C] after 16 hoursFigure 5: Moisture distribution in the wall (x100) after 16 hoursBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 11. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyStress analysis1.21.82.4stress[MPa]-1.2-0.600.60 2 4 6 8 10 12 14 16 18 20stress[MPa]time [days]Figure 6: Stress σx in time for cracked (surface) elementBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 12. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyStress analysis(a) at expansion (16 hours) (c) at contraction (4.5 days)Figure 7: Stress distributionBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 13. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyParametric study of thermalmoisture cracking(a)XZ=0m (b)YZ=3.5m(c)XZ=0.35m (d)YZ=10mFigure 8: Cracking patternbasic caseAnalysed parameters:1 Tp and Tz2 time of formworkremovalBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 14. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyInuence of placing and adjoining concrete temp. di.(a) XZ=0m (b) YZ=3.5m(c) XZ=0.35m (d) YZ=10mFigure 9: CrackingTp = Tz = 15◦C(a) XZ=0m (b) YZ=3.5m(c) XZ=0.35m (d) YZ=10mFigure 10: CrackingTp = 15◦C, Tz = 25◦CBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 15. IntroductionNumerical modelAnalysis of RC wallConclusionsGeneral caseParametric studyInuence of time of formwork removal(a) XZ=0m (b) YZ=3.5m(c) XZ=0.35m (d) YZ=10mFigure 11: Crackingremoval after 7 days(a) XZ=0m (b) YZ=3.5m(c) XZ=0.35m (d) YZ=10mFigure 12: Crackingremoval after 25 daysBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 16. IntroductionNumerical modelAnalysis of RC wallConclusionsConclusionsImportanceneed to ensure desired service life and function of the structureon-going examination of early-age cracking problemNumerical modelqualitatively and quantitatively proper resultsconformation with present knowledge and experienceContributionmulti-parameter numerical model of thermalmoisture eects inearly-age concrete and its implementationBarbara Klemczak, Agnieszka Knoppik Early-age thermalmoisture eects in RC wall
  • 17. AMCM 2011Cracow, 14 June 2011