AGEING TESTING OF PLASTIC-BASED JOINT SEALANTS FOR PRECAST CONCRETE CONSTRUCTION BY MEANS OF ARTIFICIAL WEATHERING AND SIMULTANEOUS MECHANICAL STRESS

ALTERUNGSPRUEFUNG VON FUGENDICHTUNGSMASSEN AUF KUNSTSTOFFBASIS FUER DEN BETONFERTIGTEILBAU DURCH KUENSTLICHE BEWITTERUNG BEI GLEICHZEITIGER MECHANISCHER BEANSPRUCHUNG

IN ORDER TO DETERMINE THE AGEING BEHAVIOUR OF IMPERMEABLE JOINTING MATERIALS MODEL JOINTS WERE SUBJECTED SIMULTANEOUSLY TO AGEING FACTORS (HEAT, COLD, WATER, LIGHT) AND STRESSED BY MECHANICAL DEFORMATION (STRETCHING, COMPRESSION). TO DO THIS, ONLY ONE ELONGATION-COMPRESSION INSTRUMENT WAS TRIED OUT AT THE AMBIENT TEMPERATURE OF THE CONDITIONING CABINET. THE TESTS SHOWED THAT THE EQUIPMENT ITSELF WAS QUITE GOOD BUT DID NOT FUNCTION SUFFICIENTLY RELIABLY OVER LONG PERIODS. FROM TESTS CARRIED OUT ON 5 DIFFERENT IMPERMEABLE JOINTING MATERIALS THE FOLLOWING FACTS EMERGED: A) THE LIGHT STRESSING (XENON) CAUSED SOMEWHAT GREATER PERMANENT DEFORMATIONS OF THE JOINTING MATERIALS BUT, WITHIN THE FRAMEWORK OF THESE TYPES OF COMBINED TESTS, MUST BE PERFORMED LESS ON A TIME-LAPSE BASIS. B) THE COMBINED TEST GIVES AN EXCEPTIONALLY GOOD IDEA OF THE BEHAVIOUR OF IMPERMEABLE JOINTING MATERIALS WHEN PREMATURELY STRESSED. C) IN ORDER TO STUDY THE AGEING BEHAVIOUR OF THOROUGHLY SET JOINTING MATERIALS UNDER COMBINED STRESSING, TWO-COMPONENT IMPERMEABLE JOINTING MATERIALS MUST BE HEAT-TREATED PREVIOUSLY.