POSSIBLE WAYS OF REPAIRING MOVEMENT CRACKS IN EXTERNAL WALLS BY REINFORCED LAYERS

UNTERSUCHUNGEN UEBER DIE MOEGLICHKEITEN DER REPARATUR VON BEWEGUNGSRISSEN IN AUSSENWAENDEN DURCH ARMIERTE BESCHICHTUNGEN

IN ORDER TO INCREASE TENSILE STRENGTH, COATINGS BASED ON SYNTHETIC RESIN DISPERSIONS ARE PROVIDED WITH FIBRE ADDITIVES OR STRENGTHENED BY FIBRE WEAVES. HOW FAR CRACKS IN THE SUBSTRATE CAN BE PERMANENTLY REMEDIED WAS EXAMINED BY CARRYING OUT TESTS ON NATURALLY WEATHERED SAMPLES AND WALL SURFACES - WITH THE FOLLOWING RESULTS: REINFORCEMENT ENSURES THAT THE STRAINS ARISING IN THE COATING IN THE WIDENING OF A CRACK ARE NOT RESTRICTED TO THE IMMEDIATE VICINITY OF THE CRACK BUT ARE DISTRIBUTED OVER A WIDE AREA AND ARE THEREFORE REDUCED. WITH THE SUBSEQUENT REDUCTION OF THE CRACK THE ELASTICALLY STRETCHED FIBRES CAN PROVIDE THE NECESSARY RESTORING FORCE IN ORDER TO RETURN THE COATING TO ITS ORIGINAL SHAPE. DESPITE THIS DESIRABLE EFFECT OF A REINFORCEMENT THE POSSIBILITY OF A PERMANENT REMEDY FOR CRACKS WHICH MOVE WITH TIME IS SLIGHT. AS A RULE, ONLY CRACKS SHOWING MOVEMENT IN THE ORDER OF MAGNITUDE OF 0.1 MM CAN BE COVERED WITH REINFORCED COATINGS.