Development of a non-destructive test to quantify damage in deteriorated concrete

A non-destructive test to quantify the degree of deterioration in concrete is described. Developed originally for the assessment of concrete damaged by Alkaki–Aggregate Reaction, the test has potential as a technique to measure the degree of internal damage caused by other actions such as thermal cycling, fire and impact loading. To date, the test has been applied to approximately 1000 core specimens from concrete displaying varying degrees of deterioration, and it appears to be robust and repeatable. In the test a sensitive compressometer is used to measure strain during cycles of compressive load applied at a slow strain rate by a servo-controlled machine. Data are recorded and processed automatically on a microcomputer. Subsequent calculation of hysteresis and stiffness permits a number of damage parameters to be established for each specimen. Early results indicate a strong correlation between these parameters and the degree and nature of the observed damage.