REPLACEMENT OF FROST BLANKETS BY EQUIVALENT ASPHALT LAYERS EVALUATION OF AN EXPERIMENTAL SECTION OF ROAD

ERSATZ DER FROSTSCHUTZSCHICHTE DURCH AEQUIVALENTE ASPHALTSCHICHTEN

DEPOSITS OF SATISFACTORY, FROST-RESISTANT MATERIAL FOR THE CONSTRUCTION OF CONVENTIONAL FROST BLANKETS IN ROADS ARE GRADUALLY BEING REDUCED BECAUSE OF THE ENORMOUS DEMAND, BOTH AT PRESENT AND IN THE FUTURE. IN FUTURE IT WILL BE NECESSARY PARTICULARLY IN SEVERAL AREAS OF AUSTRIA, TO TRANSPORT GOOD FROST-RESISTANT GRAVEL OVER LONG DISTANCES, AND THUS TO INCUR HIGH TRANSPORTATION COSTS. HAVING STARTED IN AMERICA, THE REPLACEMENT OF FROST BLANKETS BY BITUMINOUS MIXTURES HAS FOUND A FOOTING IN EUROPE. THE PRINCIPLE OF THIS METHOD LIES IN THE FACT THAT THE THICKNESS OF THE ASPHALT LAYER WHICH IS EQUIVALENT TO THE CONVENTIONAL FROST BLANKET CAN BE REDUCED TO ABOUT A THIRD. APART FROM THE REDUCTION IN TRANSPORTATION REQUIRED FOR THESE FROST BLANKETS, THERE ARE A NUMBER OF OTHER ADVANTAGES OF THE METHOD. THE MANUFACTURE OF BITUMINOUS MIXTURE IN CONVENTIONAL MIXING PLANTS ENSURES A DEFINITE QUALITY OF THE MATERIAL, AND CAN ALSO BE CONTROLLED BY WELL-KNOWN TEST METHODS. THE LAYING OF A DEFINED MATERIAL USING CONVENTIONAL EQUIPMENT FACILITATES THE CONSTRUCTION OF COURSES WITH A CONSTANT QUALITY. THE STABILITY OF THESE COURSES AND THEIR ABILITY TO DISTRIBUTE LOAD IS NOT IMPAIRED BY HIGH TRAFFIC VOLUMES WHEN THE STRUCTURE IS BEING USED, AS IS OFTEN THE CASE WHEN AIR PENETRATES INTO THE UNBOUND GRAVEL ROADBASE AND IT BECOMES SATURATED, ESPECIALLY IN STRING.