Performance of Grouts for Post-Tensioned Bridge Structures

摘要

Selection of an appropriate grout mix for filling the ducts of post-tensionedbridge structural elements is an important task that could provide long-term protection of post-tensioning steel against corrosion. Important properties of a suitable grout mix include its workability, protection against corrosion of steel, low permeability, ability to expand, high compressive strength, ability to bond to the steel and duct, and overall durability. To identify the most appropriate grout mix for the post-tensioning application, a test program was carried out in this study to evaluate 15 different grout mixes that had shown promise based on an evaluation of existing literature and data. These mixes included pozzolanic materials, i.e., portland cement and commercially available grouting admixtures. For each grout, several properties were determined. The findings included results on the expansion and shrinkage, bleeding characteristics, compressive strength, flow time, permeability, pH of bleed water, setting time, and surface corrosion observations of the post-tensioning steel surrounded by each mix.