Four previous issues of HPC Bridge Views* have contained descriptions of changes
needed in the AASHTO Specifications to facilitate the implementation of HPC.
The proposed revisions are based on work performed as part of a pooled-fund project
administered by the FHWA as Project No. DTFH61-00-C-00009.
At its June 2003 Annual Meeting, the AASHTO Subcommittee on Bridges and
Structures approved a number of revisions to the LRFD Bridge Design Specifications and
the LRFD Bridge Construction Specifications to facilitate the implementation of high performance
concrete. Although some of the changes were initiated because of the use of high
strength concrete, the changes will apply to all high performance concrete. Please note
that the following is only a summary of the approved revisions. The revisions do not
become the official specification articles until they are published by AASHTO in 2004, at
which time, they will have the following impact:
Design Specifications
Recognize that concrete unit weight increases as concrete compressive strength increases
(Table 3.5.1-1)
Extend some provisions to concrete compressive strengths greater than 10.0 KSI (Articles
5.1 and 5.4.2.1)
Facilitate specifying concrete compressive strengths at ages other than 28 days (Article 5.3)
Allow the use of ground granulated blast-furnace slag (Article C5.4.1)
Allow higher cementitious materials content for high strength concrete (Article 5.4.2.1)
Construction Specifications
Introduce two new classes of high performance concrete (Articles 8.2, 8.3.1, 8.4.1, 8.4.4,
8.6.6, 8.6.7, and 8.11.1)
Allow the use of ASTM 1157 Blended Hydraulic Cement (Article 8.3.1)
Allow a combined aggregate grading (Article 8.3.5 and a new Appendix)
Allow the use of ground granulated blast-furnace slag (Articles 8.3.7, 8.4.4, and 8.6.4.1)
Allow higher cementitious materials content for high strength concrete (Article 8.4.3)
Recognize the use of 4×8-in. cylinders (Article 8.5.7.1)
Facilitate concrete compressive strengths being specified at ages other than 28 days (Articles 8.5.7.3 and 8.5.7.5)
Require the use of match-cured cylinders for high strength concrete (Article 8.5.7.5)
Ensure proper curing of high performance concrete (Articles 8.6.4.1, 8.11.1, 8.11.3.5, 8.11.4, and 8.13.4)
In addition to the above revisions, other changes are under consideration by the AASHTO Subcommittee on Bridges and Structures and the AASHTO Subcommittee on Materials. These changes will be described in future editions of HPC Bridge Views.
*See HPC Bridge Views, Issue Nos. 23, 24, 25, and 28