National Concrete Pavement Technology Center

Project description

Because of its unique nature, self-consolidating concrete (SCC) has the potential to significantly reduce costs associated with transportation-related infrastructure, benefiting both MoDOT and the residents of Missouri. SCC is a highly flowable, nonsegregating concrete that can be placed without any mechanical consolidation, and thus has the following advantages over conventional concrete: decreased labor and equipment costs during concrete placement, decreased potential for and costs to repair honeycombing and voids, increased production rates of precast and cast-in-place (CIP) elements, and improved finish and appearance of cast and free concrete surfaces. In addition to SCC, innovative materials, such as high-volume fly ash concrete (HVFAC), also provide a significant potential to produce more cost effective mix designs for CIP concrete. Since the 1930’s, fly ash – a pozzolanic material – has been used as a partial replacement of portland cement in concrete to improve the material’s strength and durability, while also limiting the amount of early heat generation. From an environmental perspective, replacing cement with fly ash reduces the concrete’s overall carbon footprint and diverts an industrial by-product from the solid waste stream (currently, about 40 percent of fly ash is reclaimed for beneficial reuse and 60 percent is disposed of in landfills). The objective of this research was to provide an implementation test bed and showcase for the use of sustainable and extended service life concrete. In this implementation study for Missouri Bridge A7957, a level of 50% fly ash to cement proportions was utilized as well as normal strength self-consolidating concrete (NS-SCC) and high-strength self-consolidating concrete (HS-SCC) in its primary carrying elements to showcase the use of these innovative materials. This study focused on monitoring the serviceability and structural performance, both short-term and long-term, of the bridge in an attempt to investigate the in-situ behavior of the NS-SCC, HS-SCC and also the HVFAC mixtures. Consequently, to compare and demonstrate the potential benefits and savings of using NS-SCC, HS-SCC and HVFAC in the first Missouri DOT large-scale bridge structure, this study undertook ten tasks including the following: Task 1: Pre-Construction Planning and Construction Coordination; Task 2: Development of Bridge Instrumentation Plan & Load Testing Plan (Bridge A7957); Task 3: Mix Design and Quality Control Procedures/Quality Assurance – Trial Mixes; Task 4: Shear Testing and Evaluation of HS-SCC Precast NU Girders; Task 5: Precast-Prestressed Plant Specimen Fabrication and Instrumentation; Task 6: Field Cast-In-Place Elements and Instrumentation; Task 7: Hardened Properties of Plant and Field Produced Concrete; Task 8: Bridge Load Testing and Monitoring/Evaluation of Experimental Load Testing Results; Task 9: Reporting/Technology Transfer; Task 10: Value to MoDOT and Stakeholders to Implementing SCC/HVFAC. The final report consists of a summary report and four technical reports. The findings, conclusions and recommendations of the study can be referenced within these reporting components.