The Influence Of Concrete Carbonation Of Ultrasonic Detection Parameters

Ultrasound as a new nondestructive testing method has been gradually applied to concrete engineering,the test of acoustic parameters mainly include wave velocity,amplitude,frequency and waveform.Studies on the influence factors of ultrasonic testing is done mainly in the transducer coupling state,reinforcement distribution,moisture and temperature,and by the size of the test piece and so on.And whether concrete carbonization has impact on ultrasonic testing,there is no report available.To explore the influence of carbonization on ultrasonic test parameters,to the laboratory specimens of the existing research,first determine the best way to test.Then make water cement ratio of 0.37,0.45,0.53,such as the quality of fly ash to replace cement was 0%,30%,60%,100 mm * 100 mm * 400 mm of concrete specimen,After standard curing 28 d,28 d for a rapid carbonization experiment,In carbonization age of 0 d,7 d,14 d and 21 d and 28 d,wave velocity and amplitude measurement and record,at the same time with carbide specimen comparison,analysis the change between before and after.Define the relative velocity and relative amplitude of P,K to explore its relationship with the dosage of fly ash and water-binder ratio,and fitting the carbonation depth and relative velocity and the function relation between the relative amplitude.The results show that: for the same specimens,the wave velocity of the carbide increase range between 3% and 9%,and the same condition the control specimen wave velocity the biggest change is only 0.5%,may be caused by error of measurement.When 0% dosage of fly ash,concrete carbonation specimen relative wave velocity increases with the increase of water cement ratio,when the dosage of fly ash is 30% and 60%,the carbonation of concrete specimens of relative wave velocity decreases with the increase of water cement ratio,water cement ratio is the same dosage of fly ash is not at the same time,the wave velocity changes in volatility.Variations in the amplitude of carbide parts at about 10%.The same condition the control specimen of amplitude changes only between 0.5% and 2%.With the increase of carbonation depth,amplitude also increase;The same dosage of fly ash or the same water/cement ratio,amplitude change present volatility.Water/cement ratio is 0.45,variations in the amplitude of different dosage of fly ash concrete;Relative velocity and the quadratic function relation between concrete carbonation depth fitting degree is higher,and the fitting degree between the relative amplitude and carbonation depth is lower;A function with no significant difference between the quadratic function fitting,so the concrete carbonization on ultrasonic testing method,the influence of wave speed should be as a key reference,amplitude as auxiliary reference.