Abstract: A composition for admixture with road surface preparation materials to prevent formation of ice and to melt snow on the finished road surface. The composition is distributed throughout the road surface and comprises particulate thawing substances at least some of which have a watertight coating resistant to the thawing substance and to the temperature at which the composition materials are prepared for application as a road surface. The coating may, however, be worn away by mechanical action, e.g. traffic movement, to expose the thawing substance.