Comparative Study of Mechanical and Corrosion Resistance Properties of Bridge Post-Tensioning Strands.

摘要

This report summarizes the exploration of new methods of protection for the strands used in post-tensioning of concrete bridges. Companion small-scale tests of strand or grout and strand were conducted. The tests included mechanical testing to determine modulus of elasticity, yield strength, and ultimate strength. In addition a number of passive corrosion exposure tests and accelerated active corrosion tests were run. These accelerated tests included both linear polarization resistance tests and potentiodynamic tests. Strand types investigated included conventional steel strand, hot dip galvanized strand, stainless steel strand, copper-clad strands, stainless-clad strands, and flow-filled epoxy-coated strand. The results indicated that the epoxy-coated strand dominated the others in corrosion resistance and met all mechanical property requirements. The stainless-clad and stainless steel strand were only slightly behind the epoxy-coated in corrosion resistance but need improvement in mechanical properties. The stainless-clad strand met the mechanical requirements for Grade 250 but not Grade 270.