Determination of strength of concrete/rock using Schmidt hammer : Part I скачать в хорошем качестве

Determination of strength of concrete/rock using Schmidt hammer : Part I

INTRODUCTION The Schmidt hammer test was developed in 1948 for non-destructive testing of concrete hardness and was later used to estimate rock strength. With its portable, simple and affordable attributes, the Schmidt hammer (SH) is an ideal index apparatus, which underlies its increasing popularity and expanding range of applications. The SH rebound hardness value (R) is perhaps the most frequently used index in rock mechanics practice for estimating the uniaxial compressive strength (UCS) and the modulus of elasticity(E) of intact rock both in laboratory conditions and in situ. The SH is also widely used for estimating the UCS of discontinuity walls and assessing the workability, excavability and boreability of rocks by mechanical means (cutting, polishing, milling, crushing, and fragmentation processes in quarrying, drilling and tunneling). Researchers have sought to establish correlations between the SH rebound values(R) and the UCS and E for different rock types. SCOPE The use of the SH to determine the rebound hardness of rock surfaces both in laboratory conditions and in situ with an emphasis on the use of this hardness value as an index of the UCS and E of rock materials.