BONDING BEHAVIOR OF THE REHABILITATION METHOD APPLYING EPOXY RESIN SUBJECTED TO THE VARIATION OF ENVIRONMENTAL CONDITION

摘要

This paper provides the test results of the bonding characteristics of epoxy resinbased rehabilitation methods subjected to various environmental conditions with thetemperature change ranged from 20°C±20°C to 20°C±40°C,relative humidity and freeze-thaw cycle. The test results revealed that,in the deformation characteristics of each materialsubjected to the temperature change,the difference of the deformation of each materialseemed apparently to be increased in accordance with the temperature variance,regardless ofthe strength of the substrate concrete. It also showed that the ultrasonic velocity appeared tobe slower according to the temperature change,which obviously indicated that the peelinghad taken place on the interface of substrate concrete. Consequently,as the temperaturechange increased,the bond strength appeared to be decreased. From this temperature variation,two types of failure showed; the interface failure and the failure of the substrate concrete itself.According to the dry and moisture test,a distinguished change was not found in thedeformation of each material until 4 cycles of dry and moisture test. For this reason,itdemonstrated that the relative humidity did not affect the bonding behavior of eachcomponent materials until 4 cycles as well. Meanwhile,due to the effect of relative humiditytest,corresponding bond strength was reduced to 40% of that before the test. For the effect offreeze-thaw test,after 4cycles of freeze-thaw test,debonding of each component materialsoccurred. Based on small-scaled structure test,it was found that the temperature varianceresulted in debonding of rehabilitation material,epoxy resin and substrate concrete due to thedifference of thermal expansion coefficient