ESTIMATE OF THE RESISTANCE TO COMPRESSION OF CONCRETE BY NON-DESTRUCTIVE TESTS AND CORING: CASE OF A STRUCTURE IN R + 2

Abstract

Concrete quality in Algerian construction sites is generallyof medium to low quality. This has been proved throughbuilding failures after different earthquakes. In order toensure a good concrete quality and in case of doubt or non-conformity destructive tests (NDT) are performed.However, the strength estimation based on NDT tests is dif-ficult because of the variability in concrete quality within astructure or even within elements and the variability in thetests themselves. Curves and correlations are available toestimate the strength. However, these correlations weredeveloped for concrete strength classes that are generallyhigher than those observed in Algerian sites and for differ-ent materials and fabrication conditions. In this paperNDT tests using Schmidt hammer and ultrasonic velocitywere performed on columns and beams of an existingstructure. More than 3000 Schmidt hammer measurementsand 400 Ultrasonic measurements were performed. Inaddition, 203 cores were extracted and tested. High vari-ability of concrete quality was observed within the struc-ture and even within the floors and different structuralelements. Correlations between NDT tests and coresstrength were developed and compared to those proposedby the equipment manufacturers and other researchers.The results showed that the use of available correlationsoverestimate the strength of concrete.