Implementation of Self-Consolidating Concrete (SCC) for Prestressed Concrete Girders

Download or read book Implementation of Self-Consolidating Concrete (SCC) for Prestressed Concrete Girders written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-Consolidating Concrete (SCC) was first developed in Japan almost 15 years ago, and it was not until the late 1990's that the U.S precast concrete industry applied the technology to architectural and structural building elements. This study describes the first experience of using SCC for prestressed concrete bridge girders in North Carolina. A multiple-span bridge is currently under construction in eastern North Carolina using one hundred thirty AASHTO Type III girders, each 54.8 ft (16.7 m) long (NCDOT Project 8.1170903). Three girders from one production line of five girders were selected for evaluation. Two of the girders were cast with SCC and one with conventional concrete as the control. The plastic and hardened properties of both the SCC and the conventional concrete were monitored and measured. The fresh properties of SCC included unit weight, air content, slump flow, Visual Stability Index (VSI), and passing ability as measured by J-ring and L-box. Hardened concrete tests on SCC and conventional concrete included compressive strength, static elastic modulus, elastic modulus based on resonance frequency ('dynamic' modulus) at different ages, along with creep and shrinkage. The prestressing force in the girders was monitored by load cells. Finally, the three girders were tested in flexure up to the design service load to determine and compare their load-deformation characteristics. In general, two AASTHO Type III girders were successfully cast without any vibration using SCC, and exhibited virtually identical load-deflection relationships up to the design service load than that of the conventional concrete girder. SCC showed lower elastic modulus after strength adjustment, and higher creep and shrinkage than conventional concrete.