SHEETS OF CARBON FIBRE REINFORCED POLYMERS (CFRP) AS A REPAIR MATERIAL IN ORDER TO STRENGTHEN AND REPAIR CONCRETE DAMAGED BY ALKALI AGGREGATE REACTIONS

摘要

Cylindrical mortar specimens with alkali reactive aggregates have been tested in accelerated laboratory conditions. The specimens were partly restrained longitudinally by a steel rig and/or in radial directions by external CFRP (Carbon Fibre Reinforced Polymers) wrapping or subjected to free expansion partly sealed by weak elastic tape. Expansion results for the various types of specimens are presented in this paper. The results indicate that the transient E-modulus of mortar subjected to restrained AAR expansion is less than 1 GPa. Therefore, relatively small amounts of confinement by CFRP wrapping may influence the volume expansion and cracking pattern significantly. In the accelerated test the CFRP fabric seems to be capable of almost completely hindering alkali aggregate volume expansion above a certain limit. The results are used to make implications of full-scale relevance for the use of CFRP as a repair medium to prevent harmful AAR expansion in concrete columns.