Sulphur-bound soils and a lightweight aggregate sulphur concrete have been studied for potential use as structural frost insulating base materials in roadway construction. Sulphur-bound materials show rapid strength gain and sulphur has a low thermal conductivity (0.27 W/(m ∙ K)). Laboratory studies have shown, however, that, unless specially treated, sulphur-bound soil that contains significant swelling clay disintegrates in water. The laboratory studies were more favourable for the lightweight aggregate sulphur concrete and this material was used as a base course in two test sections of roadway. The test sections and a control section instrumented with thermocouples to measure temperatures to depths of 1.52 m were monitored for 6 winter months. A Dynaflect deflection apparatus was used for structural assessment. It was found that both frost penetration and the length of the subgrade freezing period were reduced and that the structural integrity of the pavement system was improved when lightweight aggregate sulphur concrete was introduced into the base course of the roadwa