Non Destructive Testing is defined as a method used to investigate the integrity of an object, material or system, without impairing its future usefulness.
It is used to determine the following : a) In place quality of Concrete b) Health of Concrete] c) Influence of Time d) Non availability of old drawings related to the structure.
Usually if material differences in Pulse Velocity are found within the structures for no apparent reasons, there is strong reason to presume that some defective or deteriorated concrete is present. High pulse velocity implies good quality of concrete.
There is no standard co-relation . One has to generate a site specific co-relation for each site/mix design.
XRF analyzer measurements determine whether lead is present in your paint or not Paint is classified as lead-based when there is 1.0 mg/cm2 (milligram of lead per square centimeter of painted surface) The laboratory report is written in terms of the amount, or weight of lead per weight of paint chips . The federal definition of lead-based paint is 0.5% lead or 5,000 milligram of lead per kilogram of paint chips.
Yes, it depends on the experience of the user. One can detect the mesh with diameter and different levels of rebars.
The accuracy of the diameter measured increase with decrease in cover. It also depends upon the diameter of the bar. For example if the cover is 30 mm and bar diameter is 25 mm the accuracy is + 1 mm. This accuracy can improve if either of these parameters i.e. diameter or cover is reduced