Revisjon av Nordtestmetode for besemmelse av betongs strekkfasthet og heftefasthet mellom betong og mørtel (NT TR 457)

Abstract

  Three Nordtest methods for testing tensile strength of concrete and bond strength between concrete substructure and cast-on layer of concrete, mortar or sprayed concrete were evaluated in this project for proposing a new revised Nordtest method. The methods evaluated were NT BUILD 204 – Concrete hardened: Tensile strength of specimens, NT BUILD 351 – Shot Crete, concrete base: Bond strength and NT BUILD 365 – Concrete, repair materials and protective coating: Bond strength, direct pull-off test. These methods have common requirements to the testing equipment. The testing focused on requirements for the geometrical properties of the test samples, both for laboratory testing as in-situ testing. With some conditions, the suggested method could be used for both type of testing. A proposal for a revised Nordtest method for replacement of these three abovementioned methods was proposed, and this method is also included in this report.