238-SCM : Hydration and microstructure of concrete with supplementary cementitious materials

Technical Committee 238-SCM

General Information

Chair: Prof. Nele DE BELIE
Deputy Chair: Dr Barbara LOTHENBACH
Activity starting in: 2011
Activity ending in: 2017

Subject Matter

Supporting the increasing utilisation of hydraulic and pozzolanic industrial by-products, natural resources and societal waste (fly ash, blastfurnace slag and other by-products and residues of thermal industrial processes, calcined clays, limestone, natural pozzolans,natural zeolites,…) to obtain more sustainable, less CO2-intensive binders for the construction industry. The TC will serve as a knowledge platform where fundamental science and practical expertise will be gathered to create a horizontal overview of the research area and to implement and promote the dissemination of more integrated generic approaches into the scientific community. One of the main challenges of the TC will consist of dealing with SCM variability and binder diversification. The following subtopics can therefore be identified:

• Quantitative characterisation of the physico-chemical properties of a wide range of traditional and potential SCMs. Identifying challenges on an expanding and evolving SCM market. (working group 1)
• SCM reactivity and overall reaction kinetics in blended cements. Determination of reaction degrees of SCM, also in ternary mixes. Interaction between Portland clinker hydration and SCM reaction. (working group 2)
• Hydrate reaction product assemblages and pore solution composition in SCM blended cements, binary and ternary mixtures. Optimisation of sulphate additions. Effect of temperature and clinker replacement proportion. (working group 3)
• Effect of SCM incorporation on the binder microstructure. Linking microstructure to performance. (working group 3)
• Interaction between SCM and commonly used admixtures (e.g. superplasticizers, air entrainers), and smart additives such as superabsorbing polymers cf. TC-internal curing. (working group 4)
• Effect of SCMs on the properties of fresh and hardened concrete (e.g. early strength development, workability, shrinkage) and curing requirements (especially for in-situ cast concrete during cold weather, mix proportioning, early strength development). Postblending vs preblending. Implications of SCM variability. (working group 4)

Durability topics are not within the scope of this TC.


I. Expected outcomes of the TC

Learning activities, outreach and public visibility

The following activities were approved:
• Internal workshop for the TC members: 29-30 March 2012, Cyprus.
• Short doctoral course on hydration and microstructure of concrete with SCM (e.g. International symposium on concrete with smart additives and supplementary cementitious materials, Cancun 12-17 August 2012, ICCC 2015)
• Organisation of conference or special sessions at conference with the possibility to publish contributions in international journals or proceedings (further to be decided upon)


Final report/deliverables:

The committee discussed the form of the final report:
• The TC has stipulated that reporting of TC findings can be chapters prepared by the different working groups that can consist of: 1. A collection of journal publications, 2. state-of-the-art reviews or both as stated in the TC proposal. Depending on the different subtopics/work groups different approaches may be adopted that should enable to better suit the targeted audience.
• It is proposed to formulate recommendations in terms of methodologies for use in research, best practice sheets and generic tools for prediction of performance.


Scope of the TC SCM working groups

1. SCM characterization

Quantitative characterisation of the physico-chemical properties of a wide range of traditional and potential SCMs. Identifying challenges on an expanding and evolving SCM market.

2. SCM reaction kinetics:

SCM reactivity and overall reaction kinetics in blended cements. Determination of reaction degrees of SCM, also in ternary mixes. Interaction between Portland clinker hydration and SCM reaction.

3. Hydration product assemblage and microstructure of SCM blended cements

Hydrate reaction product assemblages and pore solution composition in SCM blended cements, binary and ternary mixtures. Optimisation of sulphate additions. Effect of temperature and clinker replacement proportion. Effect of SCM incorporation on the binder microstructure. Linking microstructure to performance.

4. Properties of concrete containing SCMs and interaction of SCMs and admixtures in concrete

Effect of SCMs on the properties of fresh and hardened concrete (e.g. early strength development, workability, shrinkage) and curing requirements (especially for in-situ cast concrete during cold weather, mix proportioning, early strength development). Postblending vs preblending. Implications of SCM variability. Interaction between SCM and commonly used admixtures (e.g. superplasticizers, air entrainers), cf. TC-internal curing.


II. Coordinated working plan between RILEM TC SCM and the fib TG 8.12 on SCM

FIB is preparing a new TG on Supplementary Cementing Materials (SCM). They are looking for constitutive models which describe the mechanical properties as an extension to the new fib Model Code. It could be worthwhile to have a coordinated working plan between the RILEM TC and the fib TG on SCM.

Terms of reference

The TC is supposed to run for 4 to 5 years
Members will be recruited from academia and industry, based on their experience with blended cements
The work will include literature research, exchange of good practices information, journal publications and/or state-of-the-art report, if appropriate a small test program or round robin test, a short doctoral course on hydration and microstructure of concrete with SCM.

Detailed working programme

- start-up meeting: introduction of members, suggestion of new members, overview of members’ competences and experience, plan of activities, organisation of initial workshop
- small workshop for the members, in order to get an overview of experience, problems and points of attention related to concrete with SCM; decision on most important points for further TC work
- meetings and exchange of information between TC members; compilation of sheets with best practices; round robin test if appropriate
- international conference
- organisation of a short doctoral course
- summary of TC findings in one or more journal publications and/or state-of-the-art report

Technical environment

The study of SCM in blended cements or in concrete in general fits into the scope of RILEM as an organisation dealing with a range of construction materials and structural performance. The idea for this committee was initiated by members of TC-PAE "Performance of cement-based materials in aggressive aqueous environment". In relation to durability aspects, there is often discussion if models, test methods, standards, etc are appropriate also for blended cements or for concrete with SCM additions. Common interests may exist with 224-AAM (2007) (chair: Van Deventer, Secretary: Provis) Alkali Activated Materials. A related previous TC was TC FAB-67 Use of fly ash in building. Contacts will also be made with a new fib committee 8.12 "Supplementary Cementitious Materials" (will be established in May 2011).

Expected achievements

Expected benefits are
- improve the knowledge related to reactions and microstructure of concrete made with SCM
- elucidate the effect of composition and crystallinity of SCM on former aspects
- connect researchers working in the field of SCM in concrete and agree on good practices for testing
- best practices sheets for researchers and/or practitioners
- summary of TC findings in one or more journal publications and/or state-of-the-art report
- an international conference and conference proceedings for further dissemination of information
- possibly organisation or participation in a (short) doctoral course on hydration and microstructure of concrete with SCM (e.g. one-day course connected to the final conference of the TC)

Group of users

Academics, testing laboratories, industrialists, practitioners

Specific use of the results

With the increasing use of blended cement worldwide, the use of SCM coming from abroad, the change in quality of SCM, a better insight in the effect of SCM composition and crystallinity on reactions and microstructure of concrete is needed. Best practices related to the study of concrete with SCM should be available for research and testing laboratories. Optimal use of SCM may contribute to reduction of environmental impacts by the cement and concrete industry.

Active Members

  • Ing. Natalia ALDERETE
  • Dr. Carmen ANDRADE
  • Dr. Susan BERNAL LOPEZ
  • Mrs. Laurie BUFFO-LACARRIERE
  • Prof. Özlem CIZER
  • Prof. Luc COURARD
  • Prof. Nele DE BELIE
  • Dr. Christos DEDELOUDIS
  • Dr. Emmanuel DENARIÉ
  • Mr. Yuvaraj DHANDAPANI
  • Prof. Josée DUCHESNE
  • Prof. Dr. Jan ELSEN
  • Prof. Mette GEIKER
  • Prof. Elke GRUYAERT
  • Duncan HERFORT
  • Prof. R. Doug HOOTON
  • Dr. Maria C. Garci JUENGER
  • Dr. Harald JUSTNES
  • Dr. Siham KAMALI-BERNARD
  • Dr. Agnieszka J. KLEMM
  • Prof. Konstantin KOVLER
  • Dr. Marina KOZHUKHOVA
  • Dr Barbara LOTHENBACH
  • Prof. José Fernando MARTIRENA-HERNANDEZ
  • Prof. Thomas MATSCHEI
  • Dr. Esperanza MENENDEZ MENDEZ
  • Dr. Toyoharu NAWA
  • Prof. Van Tuan NGUYEN
  • Mrs Angela NUNES
  • Prof. Cédric PATAPY
  • Prof. John L. PROVIS
  • Prof. Jay SANJAYAN
  • Prof. Manu SANTHANAM
  • Prof. Karen SCRIVENER
  • Dr. Kosmas K. SIDERIS
  • Dr. Ruben SNELLINGS
  • Prof. Marios N. SOUTSOS
  • Prof. Tongbo SUI
  • Dr. Yury Andrés VILLAGRAN ZACCARDI
  • Mrs. Jeanette VISSER
  • Dr.-Ing. Anya VOLLPRACHT
  • Fengzhe WANG
  • Dr. Guang YE
  • Dr. Monika ZERVAKI
  • Mr. Jian ZHOU
  • Dr. Semion ZHUTOVSKY