Professor
B.S., University of Texas (Austin), 1958
M.S., University of Texas (Austin), 1960
Ph.D., University of Texas (Austin), 1972
Room: 4150D Learned Hall
Phone: (785) 864-2918
Fax: (785) 864-4967
E-mail:
lok@ku.edu
Corrosion of steel in portland cement concrete is a large problem in the United States because of the frequent use of de-icing salts containing chloride. The de-icing salts diffuse through the concrete and disrupt the normal passive condition of the embedded steel when the chloride ions reach the steel surface. Large potential differences are realized between the passive steel and the depassivated steel that accelerate the corrosion-caused damage. Damage to bridges has accelerated to such an extent in the past ten to fifteen years that the cost to repair the corrosion-damaged bridges is estimated at more than $4 billion.
Locke's research interests are primarily related to the development of an understanding of the corrosion process of steel in concrete. Projects funded by the National Science Foundation, the Federal Highway Administration, the Oklahoma Department of Transportation, and the University of Oklahoma were devoted to several aspects of this problem. The effects of cathodic protection level currents on the bond strength of steel in concrete indicated the long-term results of this popular corrosion-control technique may be detrimental to bond strength. Pore press studies based on analysis of concrete pore solution squeezed from the material have led to an interesting understanding of the chemistry in the portland cement concrete and its effect on the corrosion process.A study of a potential new de-icing chemical to replace the sodium chloride provided an indication that corrosion of steel in concrete can not be halted by the proposed new material. This new material, calcium magnesium acetate, is a reaction product of acetic acid and dolomitic limestone. All these projects have utilized electrochemical testing to develop the understanding of the corrosion process.
Locke is contemplating additional projects that would develop an increased understanding of the corrosion mechanism of steel in concrete. Utilization of the pore press , combined with the electrochemical tests, would be used to investigate the fundamentals of the process.
