Browsing by Author "Laurila, Timo"

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  • OVT-järjestelmän liittäminen toiminnanohjauksen kokonaisjärjestelmään
    (1995) Laurila, Timo
     Helsinki University of Technology | Master's thesis
  • Luiskamallit ja -verhoukset Saimaan kanavan kolmannessa rakentamisessa
    (1968) Laurila, Timo
     Helsinki University of Technology | Master's thesis
  • Moduloidun portaalin rakenneperiaatteiden suunnittelu
    (1986) Kuuva, Markku
     Helsinki University of Technology | Master's thesis
  • Monitoring of reinforcement corrosion by use of the galvanostatic pulse method
    (2004) Tiirikainen, Suvi
     Helsinki University of Technology | Master's thesis
    Interpretation of corrosion risk in reinforced concrete structures has been performed with a number of electrochemical techniques ever since the first half-cell potential mapping measurements were developed. The maintenance and repair of the structures requires a monitoring technique that can reliably locate the corroding areas and estimate corrosion rates. The galvanostatic pulse technique introduced in 1988 has been lately investigated as an easy, rapid and non-destructive method to assess corrosion rate of rebar steel. The aim of the study was to determine the usability of galvanostatic pulse measurement applications on corrosion monitoring of reinforced steel in concrete to assess corrosion rates. The laboratory tests were performed in simulated pore water solutions with varying chloride concentrations. The purpose of tests was to define parameters, which give the most reliable and comprehensive information of the condition of rebar steel rods. The traditional electrochemical methods as well as the galvanostatic pulse method were used to specify parameters in laboratory and they were tested using the GPM method on site. The main interest was to examine reinforced concrete structures guarded by cathodic protection. The tested galvanostatic pulse method was proved to be suitable to separate active and passive state of steel. The measurements performed in laboratory confirmed that there is one decade difference in corrosion current density values between active and passive steel. The results showed that the magnitude of the cathodic protection current and the applied measurement current do not have an excessive influence on the determined resistances. However the determination of resistance values may be disturbed related to the small applied currents if corrosion rate is high and deviations occur in the measured transient. Therefore the interrupted GPM method was more applicable because the time constants could also be used to determine the corrosion state of steel.
  • Pienjännitejakeluverkon suunnittelu tietyllä alueella
    (1973) Laurila, Timo
     School of Business | Master's thesis
  • Pneumaattisen materiaalinsiirtojärjestelmän suunnittelu
    (1981) Laurila, Timo
     Helsinki University of Technology | Master's thesis