POSSIBILITIES AND CONSEQUENCES OF WATER ABSORPTION BY HEAT INSULATING MATERIALS IN ROAD CONSTRUCTION

MOEGLICHKEITEN UND FOLGEN DER WASSERAUFNAHME DER DAEMMSTOFFE IM STRASSENBAU

THE EFFECTIVENESS OF HEAT INSULATING LAYERS IN ROAD CONSTRUCTION CAN BE SERIOUSLY IMPAIRED BY WATER ABSORPTION. EARLIER TESTS ON WATER ABSORPTION IN INSULATING MATERIALS ARE TO BE EXTENDED TO LOCALLY FOAMED POLYURETHANE HARD FOAM AND 'STYROPOR' LIGHTWEIGHT CONCRETE, BOTH SEALED WITH BITUMEN, THE FOLLOWING QUANTITIES BEING INVESTIGATED: (A) THE COEFFICIENT OF RESISTANCE TO DIFFUSION FOR WATER VAPOUR IN THERMAL EQUILIBRIUM, (B) THE WATER ABSORPTION IN UNDERWATER STORAGE IN THERMAL EQUILIBRIUM AND IN A VARYING TEMPERATURE, (C) THE 'PRACTICAL WATER ABSORPTION' IN THE LABORATORY. THE THERMAL CONDUCTIVITIES OF SPECIMENS SEPARATED BY UNDERWATER STORAGE (STYROPOR AND ROOFMATE) ARE ALSO TO BE DETERMINED.