This document discusses non-destructive testing methods for concrete, including ultrasonic pulse velocity testing, rebound hammer testing, and cover meter testing. Ultrasonic pulse velocity testing uses transducers to measure the speed of ultrasonic pulses traveling through concrete and can indicate quality, uniformity, and strength. Rebound hammer testing measures surface hardness through a spring-controlled hammer, where higher rebound values indicate stronger concrete. Cover meters use electromagnetic principles to locate and measure rebar cover thickness in concrete. Non-destructive testing allows evaluation of concrete properties without damaging the structure.