Effect of age on nondestructive tests results for existing concrete

الملخص EN

The aim of this study is to investigate the influence of the concrete age on the measurement of the nondestructive tests.

This study involves two types of the Investigational work; first type deals with field investigation on existing concrete, which the effect of concrete age on measurements of two types of nondestructive, rebound hammer and ultrasonic pulse velocity tests, was investigated in concrete structure of a multistory buildings under construction.

Repetitive nondestructive measurements were taken from the same location in different ages, the age of concrete under test at ranging 90 to 365 days.

Measurements results of the nondestructive testes exhibit slight growing with age, the average increase rate in the rebound number is 14.75 % and the average increase rate in the ultrasonic pulse velocity is 2.4 %.

Second type was the laboratory investigation for effect of concrete age on the nondestructive tests , where numbers of specimens from concrete mixes with 28 days strength ranging from 25-55 MPa were prepared and tested with nondestructive , rebound hammer and ultrasonic pulse velocity tests, were investigated for all mixes at 7, 28, 60, 90, 120 , and 180 days .

Results demonstrate that in general, nondestructive exhibit continuous increase with increasing in curing age and the mainly of was there increasing in the early ages, the increase percentage for rebound number and ultrasonic pulse velocity at age of 180 days are ranged between (15-19) % and (6.4-10.9) %, respectively as compared with that of 28 days age.