Computerized decision tree for anti-icing/pretreatment applications as a result of laboratory and field testings

Abstract

The Ohio Department of Transportation (ODOT) pretreats the roadways of Ohio two times a week with 23% NaCl at 40gal/lane∗mile application rate when weather conditions warrant. To be able to come up with the most effective anti-icing program for ODOT, field and laboratory investigation of pretreatment was studied on pavements.Brine decay was studied on highways ATH-50 PCC and PICK-23 AC versus time and traffic. The field tests for brine were conducted with modified versions of the SOBO 20 YSI BO and Wally BO.The laboratory part included the detailed investigation of issues encountered in the field due to the grooved texture of concrete and porous texture of asphalt pavements. Correction factors for the salt readings on porous asphalt and grooved concrete surfaces were developed. Based on lab data grooved and porous surfaces appeared to decrease the efficacy of pretreatment. Correction equations due to pavement–fluid temperature difference were developed.The modeling of the salt decay on state roads provided statistically good results with high R2 values. The laboratory data were integrated with the field study results by the construction of a decision tree which is the product of this research. This decision tree was also computerized by using C-Sharp Programming Language. Remaining salt density after certain time or traffic can be found from the decay equations for porous and grooved pavements and the freezing point temperatures can be obtained before an ice/snow event. By this way, the personnel can decide when to pretreat and can know to what temperature extent the salt on the pavement is effective.