详情

原文传递 Study of the Use of Self-Consolidating Concrete for the Repair of the Mead Bridges on I-25.

题名：	Study of the Use of Self-Consolidating Concrete for the Repair of the Mead Bridges on I-25.
作者：	diousis, p. d. whitcom, b. l.
关键词：	concrete structures, durability, repair, construction, steel girders, mix design, stability, slump flow, bond strength, traffic vibrations, colorado, recommendations, performance evaluation
摘要：	Self-consolidating concrete (SCC) is a stable and highly flowable concrete that consolidates without the help of external vibration and can flow through heavy reinforcement and around corners in complex formwork under its own weight. The exceptional performance of this remarkable material has attracted the attention of construction firms and DOTs in the United States interested in using SCC on new bridge construction and bridge repair projects. CSM has been granted a CDOT research project to participate in two SCC demonstration projects in the state of Colorado. The first project is part of the construction of structures P-18-BK and P-18-BM on I-25 in Trinidad, CO. The second project is the repair of abutment supports of structures D-17-DA and DB on I-25 in Mead, CO. This report presents the study and recommendations for the repairs in Mead. The Mead project addresses the problem of locking the ends of a non-composite steel-girder bridge to its abutments. SCC will be placed at the bridge end, to encapsulate the ends of the steel girders, the space between them, and the abutment. The SCC will be placed through holes at the deck into an encased area. Casting will take place one traffic-lane at a time, while the other lane is open to traffic. The concern is that a gapped and weakened bond between the new concrete and the existing structure may develop due to traffic vibrations. A stable, early-high-strength SCC mix has been developed by CSM for this project. Bridge vibrations due to traffic were recorded capturing all reasonable combinations of traffic flow and loads. Small-scale experiments were designed and performed that simulated the effects of vibrating steel girders within freshly mixed SCC as expected in the field. The effects of such action on the interface quality between the steel girders and the encasing concrete were evaluated. The SCC developed at CSM is characterized by high static and dynamic stability. It has a slump flow of at least 26 inches, a 24-hour compressive strength of 4,000 psi, and a 28-day compressive strength of 8,000 psi. Small-scale steel beams were placed within freshly mixed SCC and were subjected to the recorded traffic vibrations for 24 hours. At the end of this process, the bond strength of vibrated and un-vibrated specimens was measured by pull-out or push-through tests. It was concluded that the CSM-developed SCC mix design performed well for the purposes of this project and the loss of bond strength due to vibrations was moderate. / Supplementary Notes: Sponsored by Colorado Dept. of Transportation, Denver. Research Branch. and Federal Highway Administration, Denver, CO. Colorado Div. / Availability Note: Product reproduced from digital image. Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
总页数：	u0803；28p
报告类型：	科技报告