Midterm presentation of A Coupled Transport and Chemical Model for Durability Predictions of Cement Based Materials Mads Mønster Jensen Supervisors: B. Johannesson, M. Geiker, H. Stang, E.P . Nielsen DTU 30-11-2012 CONCRETE EXPERTCENTRE
Outline Objective and motivation Model description 2.1 General formulation of a reactive mass transport model 2.2 Mass transport and finite element parameters 2.3 Chemical modeling of hydration and initial parameters 2.4 Chemical modeling of boundary 2.5 Model databases Result of simulation Conclusion CONCRETE EXPERTCENTRE
Objective and motivation Objective ◮ Present the status of the work within, A Coupled Transport and Chemical Model for Durability Predictions of Cement Based Materials ◮ Present input/output parameters for reactive mass transport modeling in cement based materials Motivation ◮ Improve the understanding of concrete degradation, from advanced reactive mass transport modeling ◮ Specify the contribution from reactive mass transport modeling to the service life prediction framework Full project title: A Coupled Transport and Chemical Model for Durability Predictions of Cement Based Materials CONCRETE EXPERTCENTRE
Outline Objective and motivation Model description 2.1 General formulation of a reactive mass transport model 2.2 Mass transport and finite element parameters 2.3 Chemical modeling of hydration and initial parameters 2.4 Chemical modeling of boundary 2.5 Model databases Result of simulation Conclusion CONCRETE EXPERTCENTRE
Model overview Reactive mass transport model in a service life prediction Overview of the physical and chemical processes described in the coupled model Mass Transport Chemical Equilibrium Processes included in the mass Processes included in the transport model: chemical equilibrium module: - Diffusion of ions - Water reactions - Eletromigration - Pure phases - Moisture transport - Solid solution - Sorption hysteresis - Surface complexation - Diffusion of gasses Coupled model PDE system solved with FEM CONCRETE EXPERTCENTRE
Model overview Chemical equilibrium description in service life prediction Different time aspects in chemical modeling ◮ Assumed time for hydration ◮ The time for the operating structure ◮ Changing boundary conditions initiated at different times } Chemical description t hydration t service of solid matrix and pore solution t total t exposure } Chemical description t exposure of the boundary condition CONCRETE EXPERTCENTRE
Outline Objective and motivation Model description 2.1 General formulation of a reactive mass transport model 2.2 Mass transport and finite element parameters 2.3 Chemical modeling of hydration and initial parameters 2.4 Chemical modeling of boundary 2.5 Model databases Result of simulation Conclusion CONCRETE EXPERTCENTRE
Material model description Parameters for the coupled system Material parameters for mass transport calculation ◮ Tortuosity factor for porous material Spatial and transient parameters for the finite element method ◮ Length of the system considered ◮ Spatial discritization ◮ Total time ◮ Time stepping length CONCRETE EXPERTCENTRE
Outline Objective and motivation Model description 2.1 General formulation of a reactive mass transport model 2.2 Mass transport and finite element parameters 2.3 Chemical modeling of hydration and initial parameters 2.4 Chemical modeling of boundary 2.5 Model databases Result of simulation Conclusion CONCRETE EXPERTCENTRE
Material model description Initial chemical values Oxide composition for Reverse Bouge calculation of cement based material: � � Oxide[mass%] = CaO ; SiO 2 ; Al 2 O 3 ; Fe 2 O 3 ; SO 3 ; K 2 O ; Na 2 O Additional oxides may be added, e.g. MgO Degree of hydration of clinker: α i ( t ) = � � α C 3 S ; α C 2 S ; α C 3 A ; α C 2 F ; α C 4 AF ; α CS ; α KS ; α K 3 NS 4 Water to cement ratio: W / C Initial calculation determines, solid matrix composition, pore solution composition, saturation of porous system, porosity. CONCRETE EXPERTCENTRE
Outline Objective and motivation Model description 2.1 General formulation of a reactive mass transport model 2.2 Mass transport and finite element parameters 2.3 Chemical modeling of hydration and initial parameters 2.4 Chemical modeling of boundary 2.5 Model databases Result of simulation Conclusion CONCRETE EXPERTCENTRE
Boundary model description Chemical description of the boundary environment For water exposed boundary condition ◮ Ionic composition, e.g from Tronheim Fjord 1 Ca Mg Na K S Cl C g / l 0.43 1.33 10.99 0.38 0.99 21.10 0.02 ◮ Water temperature For non-water exposed boundary or mixed, e.g splash zone ◮ Relative humidity, RH ( t ) ◮ Air temperature ◮ Direct tide variation measurements or averaged functions CONCRETE EXPERTCENTRE 1 De Weerdt and Geiker 2012
Outline Objective and motivation Model description 2.1 General formulation of a reactive mass transport model 2.2 Mass transport and finite element parameters 2.3 Chemical modeling of hydration and initial parameters 2.4 Chemical modeling of boundary 2.5 Model databases Result of simulation Conclusion CONCRETE EXPERTCENTRE
Physical property database Physical properties for constituents Database for physical constants of Fixed physical constants: the constituents and phases: ◮ Dielectricity for water ◮ Ionic complexes ◮ Dielectricity in wacuum ◮ Diffusion coefficients ◮ Farradays constant ◮ Electromigration coefficient ◮ Density of water ◮ Valence ◮ Vapour saturation density ◮ Solid Species ◮ Mole weight ◮ Density ◮ Water and vapor diffusion coefficients CONCRETE EXPERTCENTRE
Predefined chemical database models State of the art Chemical degradation of the solid matrix Reactions Reactions Pure phases Solid Solution Ca ( OH ) 2 + 2H + ↔ Ca 2 + + 2H 2 O Portlandite AFm(1) (ss) Silica(am) SiO 2 + 2H 2 O ↔ H 4 SiO 4 Ca 2 Al 2 ( OH ) 10 : 3H 2 O ↔ 2Ca 2 + + 2Al ( OH ) − 4 + 2OH − + 3H 2 O MgCO 3 + H + ↔ Mg 2 + + HCO − C 2 AH 8 Magnesite Ca 2 Fe 2 ( OH ) 10 : 3H 2 O ↔ 2Ca 2 + + 2Fe ( OH ) − 4 + 2OH − + 3H 2 O 3 Mg ( OH ) 2 + 2H + ↔ Mg 2 + + H 2 O C 2 FH 8 Brucite Mg 4 Al 2 ( OH ) 14 : 3H 2 O ↔ OH-Hydrotalcite AFm(2) (ss) 4 + 6OH − + 3H 2 O 4Mg 2 + + 2Al ( OH ) − Ca 4 Al 2 ( OH ) 14 : 6H 2 O ↔ 4Ca 2 + + 2Al ( OH ) − 4 + 6OH − + 6H 2 O C 4 AH 13 CO 3 - Mg 4 Al 2 ( OH ) 14 CO 3 : 2H 2 O ↔ Ca 4 Fe 2 ( OH ) 14 : 6H 2 O ↔ 4Ca 2 + + 2Fe ( OH ) − 4 + 6OH − + 6H 2 O 4Mg 2 + + 2Al ( OH ) − 3 + 4OH − + 2H 2 O C 4 FH 13 Hydrotalcite 4 + CO 2 − K 2 Ca ( SO 4 ) 2 H 2 O ↔ Ca 2 + + 2K + + 2SO 2 − 4 + H 2 O Syngenite AFm(3) (ss) CaSO 4 : 2H 2 O ↔ Ca 2 + + SO 2 − Gypsum 4 + 2H 2 O ( CaO ) 2 Al 2 O 3 SiO 2 : 8H 2 O ↔ 2Ca 2 + + 2Al ( OH ) − 4 + OH − + 2H 2 O C 2 ASH 8 4 + H 3 SiO − CaCO 3 ↔ CO 2 − 3 + Ca 2 + Calcite ( CaO ) 2 Fe 2 O 3 SiO 2 : 8H 2 O ↔ 2Ca 2 + + 2Fe ( OH ) − 4 + OH − + 2H 2 O CaSO 4 ↔ Ca 2 + + SO 2 − 4 + H 3 SiO − C 2 FSH 8 Anhydrite 4 ( CaSiO 3 ) 2 ( CaSO 4 ) 2 ( CaCO 3 ) 2 ( H 2 O ) 30 ↔ Thaumasite AFm(4) (ss) 6Ca 2 + + 2H 3 SiO − 4 + 2OH − + 26H 2 O 4 + 2CO 2 − 3 + 2SO 2 − ( CaO ) 3 Al 2 O 3 ( CaSO 4 ) : 12H 2 O ↔ 4Ca 2 + + 2Al ( OH ) − 4 + 4OH − + 6H 2 O C 4 A ¯ 4 + SO 2 − C 4 A ¯ SH 12 CH 11 ( CaO ) 3 Fe 2 O 3 ( CaCO 3 ) : 11H 2 O ↔ C 4 F ¯ ( CaO ) 3 Fe 2 O 3 ( CaSO 4 ) : 12H 2 O ↔ 4Ca 2 + + 2Fe ( OH ) − 4 + 4OH − + 6H 2 O 4Ca 2 + + 2Fe ( OH ) − 3 + 4OH − + 5H 2 O SH 12 4 + SO 2 − 4 + CO 2 − C 4 F ¯ ( CaO ) 3 Al 2 O 3 ( CaCO 3 ) : 11H 2 O ↔ CH 11 Hydrogarnets (ss) 4Ca 2 + + 2Al ( OH ) − 3 + 4OH − + 5H 2 O 4 + CO 2 − ( CaO ) 3 Al 2 O 3 : 6H 2 O ↔ 3Ca 2 + + 2Al ( OH ) − 4 + 4OH − CaAl 2 ( OH ) 8 : 6H 2 O ↔ Ca 2 + + 2Al ( OH ) − C 3 AH 6 CAH 10 4 + 6H 2 O ( CaO ) 3 Fe 2 O 3 : 6H 2 O ↔ 3Ca 2 + + 2Fe ( OH ) − C 3 FH 6 4 + 4OH − Al ( OH ) 3 ( am ) Al ( OH ) 3 + OH − ↔ Al ( OH ) − 4 Al ( OH ) 3 + 3H + ↔ Al 3 + + 3H 2 O Gibsite AFm(5) (ss) Fe ( OH ) 3 ( am )+ 3H + ↔ Fe 3 + + 3H 2 O Fe ( OH ) 3 ( am ) ( CaO ) 3 Al 2 O 3 ( Ca ( OH ) 2 ) 0.5 ( CaCO 3 ) 0.5 : 11 . 5 H 2 O ↔ 4 Ca 2 + + 2Al ( OH ) − 4 + 0 . 5 CO 2 − Al ( OH ) 3 ( cr )+ 3H + ↔ Fe 3 + + 3H 2 O C 4 A ¯ Fe ( OH ) 3 ( cr ) C 0 . 5 H 12 3 + 5OH − + 5 . 5 H 2 O Solid Solution ( CaO ) 3 Fe 2 O 3 ( Ca ( OH ) 2 ) 0.5 ( CaCO 3 ) 0.5 : 11 . 5 H 2 O ↔ 4 Ca 2 + + 2 Fe ( OH ) − 4 + 0 . 5 CO 2 − C 4 A ¯ 3 F 0 . 5 H 12 + 5 OH − + 5 . 5 H 2 O C-S-H (ss) ( CaO ) 0.66 ( SiO 2 )( H 2 O ) 1.5 + 1 . 32 H + ↔ TobH AFt(1) (ss) 0 . 66 Ca 2 + + H 4 SiO 4 + 0 . 16 H 2 O Ca 6 Al 2 ( SO 4 ) 3 ( OH ) 12 : 26H 2 O ↔ 6Ca 2 + + 2Al ( OH ) − 4 + 4OH − + 26H 2 O 4 + 3SO 2 − ( CaO ) 0.83 ( SiO 2 ) 0.66 ( H 2 O ) 1.83 + 1 . 66 H + ↔ Al-Ettringite TobD 0 . 83 Ca 2 + + 0 . 66 H 4 SiO 4 + 1 . 34 H 2 O Ca 6 Fe 2 ( SO 4 ) 3 ( OH ) 12 : 26H 2 O ↔ 6Ca 2 + + 2Fe ( OH ) − 4 + 4OH − + 26H 2 O 4 + 3SO 2 − Fe-Ettringite ( CaO ) 1.33 ( SiO 2 )( H 2 O ) 2.16 + 2 . 66 H + ↔ JenH AFt(1) (ss) 1 . 33 Ca 2 + + H 4 SiO 4 + 1 . 49 H 2 O Ca 6 Al 2 ( SO 4 ) 3 ( OH ) 12 : 26H 2 O ↔ 6Ca 2 + + 2Al ( OH ) − 4 + 4OH − + 26H 2 O 4 + 3SO 2 − ( CaO ) 1.5 ( SiO 2 ) 0.66 ( H 2 O ) 2.5 + 3 . 00 H + ↔ Al-Ettringite JenD 0 . 66 Ca 2 + + H 4 SiO 4 + 0 . 16 H 2 O Tricarboaluminate Ca 6 Al 2 ( CO 3 ) 3 ( OH ) 12 : 26H 2 O ↔ 6Ca 2 + + 2Al ( OH ) − 3 + 4OH − + 26H 2 O 4 + 3CO 2 − CONCRETE Lothenbach, CemData07 EXPERTCENTRE
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