Experimental Behavior of Precast Bridge Deck Systems with Non-Proprietary UHPC Transverse Field Joints.

Mohamed Abokifa,Mohamed A Moustafa

doi:10.3390/ma14226964

Abstract

Full-depth precast bridge decks are widely used to expedite bridge construction and enhance durability. These deck systems face the challenge that their durability and performance are usually dictated by the effectiveness of their field joints and closure joint materials. Hence, commercial ultra-high performance concrete (UHPC) products have gained popularity for use in such joints because of their superior mechanical properties. However, the proprietary and relatively expensive nature of the robust UHPC mixes may pose some limitations on their future implementation. For these reasons, many research agencies along with state departments of transportation sought their way to develop cheaper non-proprietary UHPC (NP-UHPC) mixes using locally supplied materials. The objective of this study is to demonstrate the full-scale application of the recently developed NP-UHPC mixes at the ABC-UTC (accelerated bridge construction university transportation center) in transverse field joints of precast bridge decks. This study included experimental testing of three full-scale precast bridge deck subassemblies with transverse NP-UHPC field joints under static vertical loading. The test parameters included NP-UHPC mixes with different steel fibers amount, different joint splice details, and joint widths. The results of this study were compared with the results of a similar proprietary UHPC reference specimen. The structural behavior of the test specimens was evaluated in terms of the load versus deflection, reinforcement and concrete strains, and full assessment of the field joint performance. The study showed that the proposed NP-UHPC mixes and field joint details can be efficiently used in the transverse deck field joints with comparable behavior to the proprietary UHPC joints. The study concluded that the proposed systems remained elastic under the target design service and ultimate loads. In addition, the study showed that the use of reinforcement loop splices enhanced the load distribution across the specimen’s cross-section.

Highlights

Cast-in-place (CIP) construction techniques have been widely used for many years in the construction of bridge decks around the nation
Two typical NP-ultra-high performance concrete (UHPC) mixes were used in this study that differed only in the percentage of the steel fibers included in the mix (i.e., 1% versus 2% by volume, which corresponds to 3% versus 6% by weight)
This paper summarizes the main results of the comprehensive full-scale experimental testing of representative precast bridge deck panels with non-proprietary UHPC (NP-UHPC) transverse field joints

Summary

Introduction

Cast-in-place (CIP) construction techniques have been widely used for many years in the construction of bridge decks around the nation. The use of traditional joint closure materials like conventional concrete and non-shrink grouts for such joints has resulted in either relatively wide joints because of the required longer development length, or narrow joints with mechanical splicing of reinforcement or post tensioning These types of joints require longer time and effort to fabricate than using advanced materials like UHPC, they are not adequate as ABC techniques. They developed an NP-UHPC mix with a 30% cement slag replacement by weight to reduce the overall cost of the material This NP-UHPC mix was selected by the ABC university transportation center (ABC-UTC) for further experimental testing in different ABC applications, such as the bridge deck field joints. UNR was part of this wide research project and our role was to experimentally test the same NP-UHPC mix using locally available materials in the NV and CA states in the bridge deck field joints.

Objectives

Results

Conclusion