Abstract
This study intended to estimate the strength of ultrahigh strength concrete by estimating the compressive strength of its mock-up using a rock test hammer and provide reference data for an intensity estimation technique for ultrahigh strength concrete in the future. According to test results, existing equations mainly used for strength estimation showed differences when the data from this test were applied. The equations appeared to underestimate the surveyed data when the compressive strength was greater than 30MPa and other equations were also far off the range of surveyed data in all strength ranges. Furthermore, the rock test hammer showed higher correlation than N-type Schmidt hammer regardless of the hitting direction and the inclusion of coarse aggregate concerning W/B type, and mortar showed a little higher correlation than concrete. The measurement of rebound of the mock-up in relation to the inclusion of coarse aggregate showed that mortar's variation coefficient and standard deviation were lower than those of concrete, and the variation coefficient decreased in proportion to the size of coarse aggregate and showed more accurate value.
