Predicting the Uniaxial Compressive and Tensile Strengths of Gypsum Rock by Point Load Testing

A study was conducted to compare all of the point load test (PLT) methods and their usefulness in practical applications. The study presented the point load strength index (PLSI) obtained by three methods and established the relationships between them. Empirical equations relating uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) were developed to obtain simple, fast, practical, and economical estimates of the UCS and BTS of gypsum rocks. Ninety cores and irregular specimens were prepared from the gypsum rocks, and each sample was subjected to three types of point load testing. Laboratory core drill and saw machines were used to prepare cylindrical specimens with diameters of 56.70 mm having variable length-to-diameter ratios (L/D). The UCS tests for fresh rocks were carried out on cylindrical specimens under dry and saturated conditions following the recommendations of ISRM.