REPLACEMENT OF THE FROST BLANKET BY STYROPOR-CONCRETE LAYERS BELOW CONCRETE SURFACINGS

ERSATZ DER FROSTSCHUTZSCHICHT DURCH STYROPOR-BETONSCHICHTEN UNTER BETONFAHRBAHNDECKEN

THE PREPARATION AND SUPPLY OF HIGH-GRADE GRAVELLY SAND, SUCH AS IS REQUIRED IN EVER GREATER AMOUNTES FOR THE CONSTRUCTION OF STRONG AND FROST-RESISTANT ROADS, IS BECOMING MORE AND MORE DIFFICULT. FOR THIS REASON MORE AND MORE IMPORTANCE IS BEING ATTACHED TO PROCEDURES WHICH ENABLE THE CONVENTIONAL 50-60 CM THICK FROST BLANKET TO BE REPLACED BY HEAT-INSULATING COURSES. AS PART OF THE RESEARCH PROJECT, INSULATING COURSES OF STYROPOR CONCRETE ARE TO BE INSTALLED BELOW A CONCRETE SURFACING. THE MATERIAL OF THE INSULATING COURSE IS A MIXTURE OF CEMENT, WATER AND EXPANDED PLASTIC SPHERES, AND IS LAID DIRECTLY ON TO THE PREPARED SUBGRADE PLANUM. THE STYROPOR CONCRETE LAYER IS LIGHTER THAN WATER BUT HAS A STRENGTH WHICH ENABLES IT TO BE USED BY CONSTRUCTION SITE VEHICLES A FEW DAYS AFTER IT HAS BEEN LAID. AS VERY LITTLE INFORMATION IS AVAILABLE ON LONG-TERM BEHAVIOUR UNDER TRAFFIC, BOTH THE STRESSES WHICH OCCUR AND THE HEAT-INSULATING ACTION ARE TO BE OBSERVED AND EVALUATED OVER A PERIOD OF SEVERAL YEARS. THE RESEARCH IS INSTIGATED BY THE AUSTRIAN INSTITUTE FOR CEMENT RESEARCH.