Technical Committee 238-SCM
General Information
Deputy Chair: Dr Barbara LOTHENBACH
Activity ending in: 2017
Cluster A
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.
