DEVELOPMENT AND EVALUATION OF NONCHLORIDE ANTIFREEZE ADMIXTURE

The Law for the Prevention of Spiked Tire Dust was announced in June 1990 to solve the problem of dust produced by spiked tires. The use of chloride antifreeze admixture for control of winter road surface in cold snowy regions has shown since then a tendency to increase year by year. The percentage of total snow removal costs spent on antifreeze admixture spreading has been increasing steadily. Currently the majority of antifreeze admixture used in Japan is a chloride type (calcium chloride, sodium chloride, etc.). Concern with its effects on roadside environments and structures also has appeared. This report presents the state of development of nonchloride antifreeze admixture that inflicts little salt damage. It also reports on the results of laboratory evaluations of various compounds and on the results of field test spreading of antifreeze admixture. Simultaneous spreading of chloride antifreeze admixture (calcium chloride) and the nonchloride one (sodium acetate) was done. The comparison of the effect was carried out by the skid friction coefficient and a questionnaire survey of operators driving snow graders and snow removal trucks. Though the calcium chloride spreading section generally exceeded slightly the sodium acetate section, in a few cases the sodium acetate showed better results. It is necessary to improve nonchloride antifreeze admixture and carry out research toward proposed spreading techniques.