Use of High-Performance Concrete for Bridge Abutments: A Case Study

As part of an FHWA program to use high-performance concrete (HPC) in bridges, the state of Ohio constructed an adjacent box girder HPC bridge. HPC was used both for the prestressed and precast girders and for the cast-in-place abutments. The abutment mix was primarily designed for durability by using a low water-to-cementitious material ratio and pozzolanic materials. Before construction, laboratory trial mixes were run by using the actual material that was to be used in the abutments. After verifying the suitability of the mix in the laboratory, a few large trial batches were made at the ready-mix concrete plant to verify the plastic and hardened properties of the mix. During construction of the bridge, several problems occurred. Just before construction began, the coarse aggregate failed the state inspection and a new source of coarse aggregate had to be found. Unfortunately, HPC is sensitive to changes in aggregate, but there was no time to create trial batches before construction began. As a result, the mix had to be adjusted during construction. Soon after the initial abutment pours were made, differential shrinkage cracking was found. This was due to problems with inadequate curing. After a few tries, the mix problems were corrected and proper curing eliminated most of the cracking. Specific recommendations for quality control are made on the basis of the experience gained.