208-HFC : High performance fibre reinforced cementitious composites
Technical Committee 208-HFC
Deputy Chair: Dr. Gregor FISCHER
Activity ending in: 2011
High Performance Fibre Reinforced Cementitious Composites (HPFRCC) is a unique class of concrete material exhibiting strain-hardening behaviour under uniaxial tension, in contrast to tension-softening behaviour in most other cementitious materials. The development of HPFRCC has been rapid in the last decade, and especially in the last several years, to the point where industrial applications are being developed. Despite the obvious advantages of HPFRCC and significant amount of research worldwide, there remain a number of obstacles to their wide adoption in practice. The broad objective of this Committee is to identify and develop systematic solutions to these obstacles in relation to structural design, material property characterization and testing, and field execution. The focus will be on HPFRCC in structural applications, so that the linkage between materials and structures must be emphasized in all aspects of work of this TC.
Terms of reference
The estimated time needed for the work is 4-5 years. The following working package/time schedule is proposed:
(1) State-of-the-art report in conjunction with a preliminary international workshop (year 1)
(2) Round-robin experiments (year 2-3)
(3) Report in Materials and Structures (year 4)
(4) International concluding workshop (year 5)
Detailed working programme
In year 1, a preliminary workshop will be organized to define the state-of-the-art of HPFRCC for structural applications. A proceeding volume will document the most up-to-date information on the behaviour of HPFRCC and their elevation to structural performance, appropriate material characterization suitable for structural design purpose, robust material testing techniques, large scale material manufacture, as well as case studies of industrial applications and full scale demonstration projects. The output of this workshop will be the definition of required research and the establishment of a round robin testing programme. The workshop proceeding will also serve as a guide for the rest of the Committee Programme. In years 2 and 3, round robin experiments will be carried out by various research and industrial groups worldwide on the behaviour of HPFRCC in uniaxial tension and flexure, as well as its durability. Test results will be published in a special issue of Materials and Structures in year 4. While not within the jurisdiction of this TC, we expect research advances based on the identified needs of the year 1 preliminary workshop will be made during years 2 to 4. An international workshop concluding the work of this TC will be held in year 5. The output of this workshop will be specific recommendations that are usable by code writing bodies (e.g. CEN in Europe and ACI in US) for implementation of HPFRCC in structural designs. It is emphasized that in all phases of the TC work, industry participation will be strongly encouraged.
Initially three subcommittees will be set up under this TC. These are:
(1) Subcommittee on characterization of mechanical properties: This subcommittee will be charged to develop recommendations on test approaches and procedures of mechanical properties of HPFRCC suitable for adoption by researchers, material suppliers, and for on-site construction quality control.
Chair: Professor H. Stang, DTU, Denmark
(2) Subcommittee on durability: This subcommittee will be charged to develop recommendations of test procedures for durability quantification of HPFRCC materials under typical service environments.
Chair: Professor F. Wittmann, Aedificat Institute Freiburg, Germany
(3) Subcommittee on structural design and performance: This subcommittee will be charged to document information on the linkage between HPFRCC material properties and elevated behaviour of structural response, in addition to developing case studies of field applications of HPFRCC in industrial and demonstration projects.
Chair: Professor K. Rokugo, Gifu University, Japan
Additional subcommittees will be appointed as needed and as the work of this TC develops.
A number of technical bodies have been discussing or acting on various aspects of HPFRCC. For example, a recent (2001-2004) JCI Committee on Ductile Fibre Reinforced Cementitious Composites has been focusing on bringing together the academic and industrial communities to advance HPFRCC in structural applications. ACI Committee 544 has been discussing the need to translate the fruits of research in FRC into structural design practice. RILEM TC TDF-162 has developed recommended testing and characterization methods for tension-softening FRC. ACI Committee 318 (on Building Code Requirements for Structural Concrete) has expressed a desire for the HPFRCC research community to bring forward “usable” information for consideration of incorporation of HPFRCC into the building design codes.
The main deliverables from this TC will be:
(1) State-of-the art report on HPFRCC from Year 1 preliminary workshop,
(2) Robust testing and meaningful characterization methods of HPFRCC for mechanical properties and for durability properties,
(3) Report on Recommendations for Implementation of HPFRCC in Structural Design from Year 5 closing workshop, and
(4) A “case book” on field applications of HPFRCC
These achievements together should significantly advance the adoption of HPFRCC for structural use worldwide. As well, they should significantly advance the consensual nature of testing and characterization of HPFRCC to produce a meaningful material database usable by the international Structural Engineering community.
Group of users
There are several targeted users of these products (in no particular order):
(1) Research Organizations: The state-of-the-art documents should be useful to establish research directions. Robust and standardized testing methods should make development of new HPFRCCs more efficient as test results can be compared with those from other research groups or material developers.
(2) Code making bodies: Recommendations in design guidelines should aid in rational incorporation of HPFRCC into safe and durable structural design codes.
(3) Structural engineers: Improved methods of HPFRCC material selection, database of HPFRCC properties meaningful to structural performance, structural design guidelines, and rational constitutive models for numerical simulation of structural response are products for this community.
(4) Funding agencies: The Year 1 preliminary workshop should sharpen the focus on needed research on HPFRCC. Funding agencies can use this information to establish national and international collaborative research programmes to reach consensually agreed goals.
(5) Construction firms (including precast industry, contractors, consultants): Field execution, including processing of HPFRCC and on-site quality control methods which are fast, robust and meaningful are important products for this group.
(6) Testing standard agencies: Recommendations of consensually built and robust testing methods should aid in creating test standards for world-wide adoptions.
(7) Material suppliers: Robust and standardized testing methods should aid in material specifications that can highlight the advantage of materials supplied by fiber and prepackaged mix manufacturers, and promote the use of HPFRCC.
Specific use of the results
This TC should aid in translating the potential benefits of HPFRCC to field realization of HPFRCC engineered structures. The economic impact on material suppliers, and design and construction firms is difficult to estimate at this time, but based on information from pilot projects is expected to be enormous. It is anticipated that more efficient, safe, reliable and durable infrastructures can be built with HPFRCC, so that the social and environmental impacts will be just as big.