Field Experience and Structural Performance of Self-Consolidating Concrete in High-Rise and Bridge Construction-VDOT’s SCC Applications in Beams and Lessons Learned (PDF)

VDOT’s SCC Applications in Beams and Lessons Learned (PDF)

Pdf Summary

The document outlines the use of Self-Consolidating Concrete (SCC) in bridge structures by the Virginia Department of Transportation (VDOT) and provides insights into practical applications and lessons learned. SCC was deployed in various projects, including an arch bridge in Fredericksburg, drilled shafts on Route 28, and several bridges such as the Nimmo Parkway and Route 33.

Key findings and lessons from these projects include:

1. <strong>Performance and Quality Control</strong>: SCC demonstrates high workability with satisfactory strength and permeability, using both normal and lightweight aggregates. However, it is sensitive to material and mixture proportions, necessitating rigorous quality control (QC) to avoid surface blemishes like bugholes and sand streaks.

2. <strong>Slump Loss and Flow Characteristics</strong>: SCC's slump flow can vary, leading to potential issues such as marginal stability and slump loss. These characteristics can be maintained by using workability retaining and retarding admixtures, ensuring uniform consolidation, especially through congested reinforcements.

3. <strong>Construction Techniques</strong>: The placement of SCC requires no mechanical vibration, making it easier for certain applications like drilled shafts. Still, forms must be robust and secure to prevent bulging or leaking, particularly under head pressure needed to flow through reinforcements.

4. <strong>Design Specifications</strong>: Current VDOT specifications for SCC include a slump flow of 26 ± 3 inches and static segregation limits, ensuring its stability.

Overall, SCC has been a valuable material for VDOT's bridge structures due to its high performance, ease of placement in tight spaces, and reduced labor costs. Nevertheless, careful planning and execution in its mix design and construction methodologies are critical to its successful application.

Keywords

Self-Consolidating Concrete

Virginia Department of Transportation

bridge structures

quality control

slump loss

construction techniques

design specifications

workability

Nimmo Parkway

Fredericksburg