In-situ concrete structure strength measurement technology (in-situ detection method) is divided into non-destructive method and partial destructive method according to its influence on the structure. Non-destructive methods mainly include rebound method, ultrasonic method, ultrasonic rebound synthesis method, ray method and maturity method. However, the partial breakage method represented by core sampling is not only direct and reliable, but also an indispensable and effective method in many cases.
The core drilling method is mainly used in the following situations:
a. When there is doubt about the test results of compressive strength of test blocks, such as high strength of test blocks and poor quality of structural concrete, or insufficient strength of test blocks and good structural quality;
B. concrete quality problems due to poor materials, construction or maintenance;
C. Concrete subjected to freezing injury, fire, chemical erosion or other damage, and concrete with inconsistent surface and internal quality;
D. it is necessary to test the concrete strength in building structures or structures that have been used for many years.