IMPACT-ECHO STUDIES OF INTERFACIAL BOND QUALITY IN CONCRETE: PART II--EFFECTS OF BOND TENSILE STRENGTH

This paper and a companion one summarize the findings of a feasibility study in which the impact-echo method was used to determine interfacial bond quality in layered concrete structures, such as bridge decks with overlays or at the interface between repair concrete and existing concrete. In this context, bond quality involves both the tensile strength and the amount of unbonded fraction of area at an interface. This paper focuses on how bond tensile strength impacts the results of impact-echo method. Results obtained from numerical, experimental, and field studies are presented. The numerical studies were used to quantify the stresses in the waves generated by elastic impact to determine whether these waves could be used as a measure of bond tensile strength. Experimental and field studies were conducted to examine impact-echo results obtained from a layered concrete plate with a variety of interface conditions varying from strongly-bonded to delaminated as well as conditions produced by removal of concrete by jackhammering and hydrodemolition. The pulloff test method was used to derive bond strengths in both the experimental and field studies. Findings revealed that the stresses generated by short-duration, elastic impacts are much too small to serve as a measure of bond tensile strength.

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  • English

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  • Accession Number: 00726915
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 7 1996 12:00AM