The Research On Rapid Nondestructive Examination Method For Long-time Behaviour Of Concrete In Site

At Present,hundreds and thousands bridges has been widely built in china of afterconstruction of several decades years,in which concrete bridge have a largeProPortion.According to statistics,concrete bridges were constructed under commonmaterials,design and construction techniques at the normal level of control.it 15aPPeared that about twenty to thirty Percent of concrete bridge behaviour shortageof long一term Performance after about two or three decades oPeration.This might cause the decline in service life and great increase in cost ofmaintenance.Even if the quality of good or Poor would be directly related to thestructural safety,if concrete bridge deficiency of long一term behavior.The traditionalmethod of testing the quality of structural concrete was mostly based on entitysamPling or standard size sPecimens.Drilling core samPles may cause damages tostructures,moreover,Pouring the standard sPrcimens are different from the structureconcrete due to the conditions of Pouring and curing,force status.It 15 alwaysdifferent between the Performance of concrete obtained from the sPecimen testing andthe actual structural concrete.Therefore,the concrete on一site insPection technologyfor concrete has become an imPortant means of quality control for concreteconstruction .Based on the existing research Products,This PaPer carries out furtherresearch on measuring and testing technique of concrete strength,elastic modulus andPermeability of concrete in long一term behavior.In order to assess more accuratelylong一term behavior of concrete,the main contents and conclusions are summarizes as:1 . In order to imProve the technology of insPection of concrete strength by thePull一out of Post一insert testing method constantly,the method for adhesive Pull out testthe strength of concrete by steel anchors can result in rational results,and can beaeffective way for on一site testing for concrete conveniently.2 .It 15 found that the method combining ultrasonic extraction with adhesivePull一out better than a single means,and can be more comPrehensively and accuratelyevaluate the Performance of concrete,and get the strength curve.3 .Non一destructive ultrasonic technique was used to test the concrete consisted ofmacadam and Pebble with aggregate size of smm一25mm and smm一3Omm.It 15obtained that the sonic sPeed of aggregate have a great effect on test results,however, can,t establish a uniform relationshiP between sonic sPeed and strength,young,smodulus of concrete.4 .The method for transforming the sPeed of ultrasonic to dynamic elasticmodulus for a corresPonded sPecimen 15 convenient and feasible to establisharelationshiP between dynamic and static elastic modulus by contrast at the sameParameter.5 .Combinng some influencing factors about concrete Permeability,the traditionalPermeability testing techonology,including some rePresentative advanced technologywere introduced and summarizede.The features and defects of them were analyzed.This Provides the reference direction for Pursuer.