Concrete quality testing in existing structures. Methods of european standards

Introduction: strength testing of cores cut from existing structures, as a rule, is believed the most reliable source of actual concrete quality information. However, this statement is true in part only. Although current European standards allow applying cut core testing for determination of actual structural condition with no restriction, they foresee that the given testing cannot replace concrete quality testing based on standard specimens taken by with the rules in effect. The study purpose is obtaining relevant information on concrete quality and structure, filler type and granularity, and seeking for answers to the following questions: is the tested concrete porous; to what extent the carbonation is developing on the surface layer; are there any defects in the structure. Materials and methods: the article considers cut core testing methods, elastic rebound measuring, pull-out method, and ultrasonic velocity measurement. Results: the article presents a review of methods for concrete quality testing in finished construction projects following the European standards. Test conditions, recommendations on specimen trimming, and main requirements for correct interpretation of the data obtained using elastic rebound and ultrasonic measurements are given. Independent methods of nondestructive testing are described. Conclusions: the study considers European methods of concrete compressive strength assessment in construction structures. One of the most promising nondestructive test methods which can be applied for concrete quality testing in existing structures seems to be a pull-out method, particularly CAPO-TEST. The research showed that the pull-out tests provide an accurate assessment of strength directly in the structure.