Technical Committee 267-TRM
Deputy Chair: Dr. Ruben SNELLINGS
Supplementary cementitious materials (SCM) are commonly used in concrete practice nowadays, either in blended cements or as separate additions into the concrete mixture. The use of cementitious and pozzolanic by-products (fly ash and other artificial pozzolans, natural pozzolans, slag, limestone, …) is one way to obtain a more sustainable binder for the construction industry and there are also benefits related to costs and some durability.
This committee follows from TC-SCM. In the work of this committee it became apparent that there is an important lack ofmethods to assess the potential reactivity of a material for use as an SCM. The most common methods which appear in standards are the Chapelle and Frattini test, but these have very serious short comings and most seriously bear no little to the contribution of an SCM to strength development in a blended cement. Furthermore these tests only focus on pozzolanic reaction so cannot be used to characterise slag. This lack becomes more serious as an increasing range of materials are proposed as SCMs – rice husk ash, ground waste glass and calcined clays for example and also combinations of SCMs, such as slag and limestone or multiple SCM systems..In parallel work in a number of laboratories has indicated the potential of fairly simple methods, based on heat output,chemical shrinkage or water content evaporated over a fixed temperature range. These give very promising correlations with strength development.
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 and capacity to carryout round robin testing with no outside funding.The work will be focussed on evaluating the most promising new methods across a wide range of SCMs and comparing these to existing test methods.
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, to select test methods and materials for study. Phase 1 will be to test a limited range of SCM in the different methods and evaluate the most promising protocols.
- Phase 1 should report after about 12 months and then in Phase 2 the most promising protocols will be selected for testing on a wider ranges of SCM and combinations thereof to verify repeatability and accuracy.
- international workshop aimed particularly at sharing results with those involved in standardisation.
- organisation of a short doctoral course
- summary of TC findings in one or more journal publications
- proposal of pre-standard.
The study of SCM in blended cements or in concrete in general fits into the scope of RILEM as an organisation dealing with arange of construction materials and structural performance. The idea for this committee was initiated by members of TC-SCM“Hydration and microstructure of concrete with supplementary cementitious materials”. A contact will be established with the CEN/TC51 to ensure the practical aspects of any proposed test.
Expected benefits are
- pre standard for reactivity testing of SCM designed to correlate with strength development and to include slags and combinations of SCM in addition to pure pozzolans.
- workshops to communicate findings to standardisation communities.
Group of users
Academics, Industrial scientists, standard committees.
Specific use of the results
The development of a new test will greatly facilitate the adoption of new materials in standards.