International Summit on Cement Hydration Kinetics and Modeling * a Summary and outcomes

1. International Summit on Cement Hydration Kinetics and Modeling*a Summary and outcomes Dr. Joseph J. Biernacki, PE Tennessee Technological University Department of Chemical Engineering August 19, 2010 Federal Highway Administration Acknowledgements The 51 Participants of the International Summit on Cement Hydration Kinetics and Modeling National Science Foundation (NIST) Federal Highway Administration (FHWA) W. R. Grace BASF Mapei Canadian Research Center on Concrete Infrastructure Natural Science and Engineering Research Council of Canada Center for Manufacturing Research, Tennessee Technological University * The International Summit on Cement Hydration Kinetics and Modeling was held on July 27, 28 and 29, 2009 in at Laval University, Quebec, Quebec City, Canada.

2. Special Acknowledgements T. Xie, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010). J. J. Thomas, Digital and Mathematical Modeling of the Nucleation and Growth of Cement Based Materials, International Summit on Cement Hydration Kinetics and Modeling (2009). S. Bishnoi, A. Kumar and K. L. Scrivener, Nucleation and Growth Kinetics and the Density of C-S-h, International Summit on Cement Hydration Kinetics and Modeling (2009). J. Bullard, How can C-S-H growth behavior be predicted? Questions from a modeling perspective, International Summit on Cement Hydration Kinetics and Modeling (2009). A. Luttge, Vertical scanning interferometry… , Kinetics Summit (2010). J. Chen, et al., “A coupled grid-indentation/SEM-EDX study on low w/c PC pastes… ,” Kinetics Summit (2010). A. A. Jeknavorian, Impact of Water Reducers and Superplasticizers on the Hydration of Portland Cement, International Summit on Cement Hydration Kinetics and Modeling (2009). D. Silva, Impact of Accelerators and Retarders on the Hydration of Portland Cement, International Summit on Cement Hydration Kinetics and Modeling (2009). L. Roberts, Admixtures of C-Ash – A Challenge to Model, International Summit on Cement Hydration Kinetics and Modeling (2009). V. Kocaba and K. L. Scrivener, Effect of SCMs on Hydration Kinetics of Cementitious Systems, International Summit on Cement Hydration Kinetics and Modeling (2009).

3. Outline • Background • Demographics of Participants • Introduction • Topical Report (based on 35 Summit presentations*) • Mechanisms (7) • Modeling (5) • Experimental Methods (9) • Admixtures (5) • Supplemental Cementitious Systems (3) • Alternative Cements (4) • Thermodynamics (2) • Roadmap *see for full presentation slides http://blogs.cae.tntech.edu/hydration-kinetics/

4. Background Summer 2007 – Biernacki, Hansen (UM) and Bullard (NIST) meet as part of ongoing NSF grant activities; we discussed and agreed to try to organize a workshop of some form on hydration kinetics Fall of 2007 – The workshop concept took on the form of a US-Canadian joint effort with invitation of researchers from the European Community; Jacques Marchand (Laval University) agreed to host the event September 2007 – Biernacki and Hansen submit proposal to NSF for US-Canadian workshop entitled, “International Summit on Cement Hydration Kinetics and Modeling” June 2008 – NSF grant award received for ~$25k Fall 2008 and Winter of 2009 – Biernacki, Constantiner (BASF) and Bullard raised an additional ~$29k including support from the FHWA and a number of industrial sponsors July 2009 – Workshop held at Laval University, Quebec, Canada

5. Participant Demographics 52 Participants 6 Countries

6. Program • Early Age Hydration (Stages I, II and III) • Mechanisms • Modeling • Instrumentation and Experimentation • Effect of Supplemental Cementitious Materials • Post Peak Hydration (Stage IV) • Thermochemicstry and Geochemical Viewpoint • Alternative Cement Systems

7. Introduction • Why is hydration important? • What is this presentation about?

8. Why is hydration important? meters micrometers centimeters millimeters nanometers

9. Hydration and Common Field Problems • Shrinkage and Related Cracking – the result of volume change autogenous drying due to hydration • Corrosion – the consequence of undesirable transport to and from the environment due to inadequately developed and/or controlled microstructure • Alkali Silica Reaction – a secondary hydration process • Adverse Admixture Interactions – unexpected or unknown effects on hydration • Curing – adequate hydration

10. Kinetics and Materials • Metals – understanding the kinetics of ore processing, solidification/crystallization and solid-state phase transformation has given us super-alloys, stainless steel, lightweight alloys, corrosion resistant metals and high temperature refractory metallurgy • Polymers – by controlling the chemical reaction kinetics of organic synthesis it is now possible to reliably produce mega-tons of polyethylene, produce designer co-polymers, liquid crystals and strong, lightweight matrix materials for composites • Semi-conductors – without detailed knowledge of the kinetics of doping modern computes would be impossible • Petroleum Refining – kinetic models make it possible for refineries to be agile machines that can move between product distributions in response to rapidly changing market demands and crude prices and availability

11. Typical Calorimetric Response Stage I – Dissolution Stage II – Dormancy Stage III –Acceleration Stage IV - Deceleration

12. What is this presentation about? This presentation will summarize some of the most recent findings related to cement hydration, both experimental and computational. The “roadmap” presented here is not a proposal, but rather a summary of research needs, it is not the answer to many question, but instead identifies what the questions are. Finally, the roadmap suggests directions in which to move, not the details of every turn.

13. Mechanisms

14. Typical Calorimetric Response Stage I – Dissolution Stage II – Dormancy Stage III –Acceleration Stage IV - Deceleration

15. Typical Calorimetric Response Stage I – Dissolution Stage II – Dormancy Stage III –Acceleration Stage IV - Deceleration • Formation of thick barrier layer (prevalent hypothesis ~1980) • Formation of hydroxylated surface (suggested hypothesis ~2001) • Etch pit to stop flow dissolution transition (suggested hypothesis ~ 200x)

16. Typical Calorimetric Response • Thermodynamic destabilization of thick barrier layer (suggested hypothesis ~2008) • Mechanical destabilization of thick barrier layer (suggested hypothesis ~20xx) • Nucleation driven (suggested hypothesis ~2009) • Surface area driven (suggested hypothesis 2010) Stage I – Dissolution Stage II – Dormancy Stage III –Acceleration Stage IV - Deceleration • Formation of thick barrier layer (prevalent hypothesis ~1980) • Formation of hydroxylated surface (suggested hypothesis ~2001) • Etch pit to stop flow dissolution transition (suggested hypothesis ~ 200x)

17. Typical Calorimetric Response • Onset of diffusion control (prevalent hypothesis ~1980) • Space filling (prevalent hypothesis ~2007) • Thermodynamic destabilization of thick barrier layer (suggested hypothesis ~2008) • Mechanical destabilization of thick barrier layer (suggested hypothesis ~20xx) • Nucleation driven (suggested hypothesis ~2009) • Surface area driven (suggested hypothesis 2010) Stage I – Dissolution Stage II – Dormancy Stage III –Acceleration Stage IV - Deceleration • Formation of thick barrier layer (prevalent hypothesis ~1980) • Formation of hydroxylated surface (suggested hypothesis ~2001) • Etch pit to stop flow dissolution transition (suggested hypothesis ~ 200x)

18. Typical Calorimetric Response • Onset of diffusion control (prevalent hypothesis ~1980) • Space filling (prevalent hypothesis ~2007) • Onset of diffusion control (prevalent hypothesis 200x) • Onset of topochemical reaction/diffusion control (2010) • Slow secondary densification (suggested hypothesis 2010) • Thermodynamic destabilization of thick barrier layer (suggested hypothesis ~2008) • Mechanical destabilization of thick barrier layer (suggested hypothesis ~20xx) • Nucleation driven (suggested hypothesis ~2009) • Surface area driven (suggested hypothesis 2010) Stage I – Dissolution Stage II – Dormancy Stage III –Acceleration Stage IV - Deceleration • Formation of thick barrier layer (prevalent hypothesis ~1980) • Formation of hydroxylated surface (suggested hypothesis ~2001) • Etch pit to stop flow dissolution transition (suggested hypothesis ~ 200x)

19. Barrier Layer Hypothesis 1. Rapid dissolution 2. Formation of meta-stable layer 3. Nucleation of stable C-S-H and destabilization of meta-stable layer 4. Growth

20. Modeling

21. Origins and Evolution of Hydration Models Particle Size Distribution Models Mass Continuity-based Models Nucleation Models Jander (1927) Avrami (1939) Taplin (1972) Ginstling (1950) Cahn (1956) Taplin (1968) Bentz 2004) (volume filling) Brown (1985) Knudsen (1984) Pommersheim (1979) Thomas (2007) Pommersheim (1987) Brown (1989) Microstructure Simulation Tools Jennings (1986) Bentz (1999) van Breugel (1995) Pignat (1999) Bullard (2008) Bishnoi (2009) 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

22. Models… 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

23. And More Models… 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

24. And… 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

25. Ginstling, Brown and Jander 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

26. Pommersheim and Clifton 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

27. Knudsen 2T. Xie and J. J. Biernacki, The Origins and evolution of cement hydration models, Comp. Concr., submitted (2010).

28. 3-pai Ca+2 4+2p(1-ai) OH- (1-p) H2SiO4-2 What really is the problem? (1-p)(bo-ao)H2O 2-p(ai+ao) Ca(OH)2 p(bi-ai) H2O 3H2O (1-p) (CaO)aoSiO2(H2O)bo C-S-H product layer original core location unreacted core p(CaO)aiSiO2(H2O)bi 3 Ca+2 + 4 OH- + H2SiO4-2 (CaO)3SiO2 2J. J. Biernacki and T. Xie, An Advanced Single Particle Model for C3S and Alite Hydration, J. Am. Ceram. Soc., submitted (2010).

29. Modelingrecent advances • J. Thomas (2007), A new approach to modeling the nucleation and growth kinetics of tricalcium silicate hydration, J. Am. Ceram. Soc., 90(10), 3282-3288. • J. Bullard (2008), A determination of hydration mechanisms for tricalicum silicate using a kinetic cellular automaton model, J. Am. Ceram. Soc., 91(7), 2008-2097. • S. Bishnoi and K. Scrivener (2009), Studying nucleation and growth kinetics of alite hydration using mic, Cem. Concr. Res, 39, 849-860. • J. J. Biernacki and T. Xie (2010, submitted), An advanced single particle model for C3S and alite hydration, J. Am. Cer. Soc.

30. cement grain Nucleation Models Bulk Nucleation Conceptual Description nuclei cement grain Avrami’s Equation

31. cement grain Nucleation ModelsBoundary Nucleation Conceptual Description cement grain Cahn’s Equation nuclei nuclei

32. J.J. Thomas, Digital and Mathematical Modeling of the Nucleation and Growth of Cement Based Materials, International Summit on Cement Hydration Kinetics and Modeling (2009).

33. J.J. Thomas, Digital and Mathematical Modeling of the Nucleation and Growth of Cement Based Materials, International Summit on Cement Hydration Kinetics and Modeling (2009).

34. S. Bishnoi, A. Kumar and K. L. Scrivener, Nucleation and Growth Kinetics and the Density of C-S-h, International Summit on Cement Hydration Kinetics and Modeling (2009).

35. S. Bishnoi, A. Kumar and K. L. Scrivener, Nucleation and Growth Kinetics and the Density of C-S-h, International Summit on Cement Hydration Kinetics and Modeling (2009).

36. S. Bishnoi, A. Kumar and K. L. Scrivener, Nucleation and Growth Kinetics and the Density of C-S-h, International Summit on Cement Hydration Kinetics and Modeling (2009).

37. Experimental data from: S. Garrault and A. Nonat, Langmuir, 17 8131-8138 (2001). J. Bullard, How can C-S-H growth behavior be predicted? Questions from a modeling perspective, International Summit on Cement Hydration Kinetics and Modeling (2009).

38. Advanced Single Particle Model - TTU Model with minimal optimization compared to experimental hydration calorimetry dataset. J. J. Biernacki and T. Xie, An Advanced Single Particle Model for C3S and Alite Hydration, J. Am. Ceram. Soc., submitted (2010).

39. “Simple” Challengesthe effect of w/c ratio Alite Type I Portland Cement J. J. Biernacki and D. Kirby, The Effect of Water to Cement Ratio on Early Age Hydration Behavior, unpublished (2010).

40. Mechanisms and Modeling Roadmap • Does a semipermeable layer actually form at early ages? An affirmative answer might lead to pathways for either preventing its formation or prolonging its existence. If there is such a layer, knowledge of the trigger for its disappearance (e.g. thermodynamic or mechanical instability) could lead to the design of admixtures for targeting that trigger. • What role is played by surface defects, such as stacking faults and dislocations, in governing the dissolution rates of clinker phases in cement? Answering this question could lead to approaches such as annealing or chemical pretreatments that could eliminate or deactivate such defects. • To what extent do species in solution adsorb on cement phases or hydration product phases and modify the dissolution or growth rates of those phases? There is persuasive evidence that adsorption of calcium sulfate onto active dissolution sites of aluminate phases is responsible for the set-controlling properties of gypsum in cement, but understanding in this area is still in its infancy. • What are the transport properties of the bulk C-S-H products formed and how do they evolve with time? • Does C-S-H form by a two-stage growth process and what is the bulk density of C-S-H as a function of time? • When and where do C-S-H nuclei form and what is the formation rate? • What factors are responsible for the strong interactions between silicates and aluminates in cement clinker hydration? There is recent experimental evidence that incorporation of aluminate ions in C-S-H is highly dependent on aluminate concentration in solution but also poisons its growth rate. • What are the form of the rate laws, e.g. what is the reaction order, and what are the elementary reactions that control the reaction rates, not only at early age, but at any age? • What is the actual morphology of C-S-H growth and what controls the morphology since many forms have been observed? • Are there signatures in early-age calorimetry measurement that indicate long-term kinetics and performance?

41. Mechanisms and Modeling Roadmap cont’d • Continue to develop various solution-phase-driven models that incorporate kinetics, thermochemistry and transport phenomena. • Develop multiple modeling paths and strategies that corroborate findings and lead towards useful engineering tools as well as model-based research instruments including fast algorithms for PC and similar platforms. • Continue to extend and exploit computational resources as necessary and needed to accommodate changing needs, i.e. utilize massively parallel processing and super computer facilities as needed. • Consider alternative computational strategies to accelerate the development of rigorous models, i.e. fast single particle models, representative volume approaches, etc. • Exploit the body of knowledge on true multi-scale modeling. • Improve the dissemination of modeling tools to promote their use and development. • Incorporate more molecular-level modeling strategies, i.e. kinetic Monte Carlo, etc. • Develop suitable structural analogs for various anhydrous and hydrated cement phases for use in molecular modeling. • Develop focused experimental program driven in part by model development and designed to provide information for parameter estimation and to answer mechanistic questions. Specific questions that must be addressed experimentally and within the construct of existing and new models to be developed are included under Mechanisms above.

42. Experimental Methods

43. Methods, “new” and “old” • “Old” • Isothermal calorimetry • IR spectroscopy • Electron microscopy and associated chemical micro-analysis (EDS/WDS) • Nuclear magnetic resonance (NMR) • Coherent and incoherent X-ray and neutron scattering • “New” • Nuclear reaction resonance analysis (NRRA) • Time-domain reflectometry dielectric spectroscopy (TDR-DS) • Vertical scanning interferometry (VSI) • Nano-X-ray tomography • Atomic force microscopy imaging and associated micro- and nano-probe techniques

44. Methods, “new” and “old” • “Old” • Isothermal calorimetry • IR spectroscopy • Electron microscopy and associated chemical micro-analysis (EDS/WDS) • Nuclear magnetic resonance (NMR) • Coherent and incoherent X-ray and neutron scattering • “New” • Nuclear reaction resonance analysis (NRRA) • Time-domain reflectometry dielectric spectroscopy (TDR-DS) • Vertical scanning interferometry (VSI) • Nano-X-ray tomography • Atomic force microscopy (AFM) imaging and associated micro- and nano-probe techniques

45. Vertical Scanning Interferometry *A. Luttge, “Vertical scanning interferometry… ,” Kinetics Summit (2010).

46. Nano-indentation *J. Chen, et al., “A coupled grid-indentation/SEM-EDX study on low w/c PC pastes… ,” Kinetics Summit (2010).

47. Nano-indentation *J. Chen, et al., “A coupled grid-indentation/SEM-EDX study on low w/c PC pastes… ,” Kinetics Summit (2010).

48. Experimentation Roadmap • Extend as necessary and apply the vertical scanning interferometry (VSI) technique in an attempt to answer at least a portion of the questions regarding mechanisms. • Further develop x-ray nano tomography into a quantitative technique and apply it to study the rate of cement phase reaction in both model systems and portland cements and for blended systems containing silica fume, blast furnace slag and fly ash. • Further explore the use of nuclear resonance reaction analysis (NRRA) as a tool for elucidating the barrier layer hypothesis. • At this time, broadband time-domain-reflectrometry (BTDR) dielectric spectroscopy (DS) is a rather elusive technique that needs to be made generally available to the community at large. The datasets coming out of the single laboratory where the experiments are being conducted also need to be made generally available to the modeling community or need to be integrated with a modeling effort in an attempt to extract mechanistic kinetic information. • More datasets that combine techniques need to be developed so that modelers can impose multiple constraints in an effort to produce unique parameter sets with physical meaning. • Establish an open network with researchers in the broader community, both those doing modeling and experimentation, so that they have access to datasets and instrument time on unique tools such as VSI, nano x-ray tomography, NRRA and BTDR-DS.

49. Admixtures

50. A. A. Jeknavorian, Impact of Water Reducers and Superplasticizers on the Hydration of Portland Cement, International Summit on Cement Hydration Kinetics and Modeling (2009).