ABSTRACT
The following examples of double combinations between simple non-destructive methods are known:
(a) longitudinal pulse velocity+rebound index (SONREB method), (b) longitudinal pulse velocity+indentation diameter, (c) longitudinal pulse velocity+pull-out force, (d) longitudinal pulse velocity+attenuation of ultrasonic pulses, (e) longitudinal pulse velocity+gamma-ray attenuation, (f) longitudinal pulse velocity+damping of vibrations, (g) longitudinal pulse velocity+transverse pulse velocity, (h) longitudinal pulse velocity+maturity concept, (i) rebound index+indentation diameter, (j) rebound index+pull-out force, (k) rebound index+maturity concept. The following examples of triple combinations between simple non-destructive
methods are known:
(a) longitudinal pulse velocity+rebound index+ pull-out force, (b) longitudinal pulse velocity+rebound index+ attenuation of ultrasonic pulses, (c) longitudinal pulse velocity+rebound index+ transverse pulse velocity, (d) longitudinal pulse velocity +slope at the first wave front +reverberation time. Due attention should be paid to the development of new simple non-destructive
methods satisfying the criteria of para. 2.4 of the Recommendation and their possible combinations with existing simple non-destructive methods, in order to build up new, efficient combined methods.
