Research On The Real-time Tecting Of Concrets Strength By Dynamic Means

On the basis of detailed analysis for the past outcomes, it was concluded that in being non-destructive testing technology couldn't be used to test the fresh concrete strength. But the concrete strength always need be inspected continuously in the concrete engineering. Aiming at this problem, the paper put forward a dynamic concrete strength testing technology-consolidating wave speed method, and it can be used to testing fresh concrete strength real-timely.The consolidating wave speed means the speed at which elastic stress wave transmits throughout reinforced concrete, and it is intervenient the inherent wave speed of steel and of the concrete. Moreover, the consolidating wave speed inherent in the material of the reinforcing steel bar and the concrete, and it relates to the cling strength of steel bar and the concrete. The changing value of the consolidating wave speed reflects the change of concrete substance parameter, and it reflects the increasing strength of the fresh concrete.The consolidating wave speed of ten concrete specimens within four kinds of composition was inspected in 28 days, and we got the analogical law that the value of consolidating wave speed changes with the increasing concrete strength: the consolidating wave speed decreases when the concrete strength increases, and they varies according with exponential function. So, the feasibility of the consolidating wave speed method was validated, and this method has the advantages that it can be used to testing fresh concrete strength real-timely. The consolidating wave speed changes distinctly in 7 days, so it makes up the loss that in being non-destructive testing technology couldn't be used to test the fresh concrete strength.Refer to the impacting-echo technology, we impacted the apex of the steel bar and incepted the reflecting stress \\ave through the resonator that fixed on the apex of the steel bar, and the value of the consolidating wave speed was calculated based on the timeof stress wave transmitted and the length of the steel bar, so, identifying the reflecting signal is the key of the consolidating wave speed method. The problem has been resolved with the wavelet analysis software that designed on the matlab5.3.