118 A Study of Practical Corrosion Diagnosis and Partial Repair Painting of Weathering Steel Bridge

Investigation on Corrosion Protection Systems and Wear Problems for a Ship Unloader

“…Suchsystemshavebeenfoundtoexperienceseriouscorrosionissuesinseveralcountries (Milana et al,2016).InJapan,preciselyintheNipponSteelCorporation,oreunloadingmachinesareproneto seriouscorrosionproblemsduetotheirexposuretomarineenvironmentsandtheircontinuoususage forover20years,causingthesteelstructuretodegradeseverely (Aigaet al2003).Toremedythe situation, Aiga,et al(2003)consequentlyproposedtodevelopalowcostandshortperiodrepainting strategytoprolongthelifetimeoftheoreunloadingmachinesandpreventfurtherdamage.Forthis study,severalfactorsweretakenintoaccountsuchastheequipment'smobility,exposuretoseashore environmentandthedowntimerequiredforrepainting.Thus,anticorrosionpaintingmethodswere proposed;oneofwhichwassprayingandtheotherwasthick-layerbrushingusingmodifiedepoxy resinpaint.Throughsaltsprayexperiments,itwasfoundthattheoptimumcoatingthicknesswas 200µm.Eventually,bothpaintapplicationmethodswereproposed,dependingonwherepaintingwas requiredonthesteelstructure (Aigaet al,2003).…”