Einfluss der belastungsart und - geschwindigkeit auf die ergebnisse von festigkeitsprürfungen an prüfzylindern aus bodenverfestigungskörpern

German technical standards for testing the compressive strength of soil-cement cylinders differ for various soil stabilization techniques (grouting, jet grouting or mixed in place): for compressive strength f_k < 5 MPa tests should be run at a constant strain rate, for f_k > 5 MPa load controlled tests should be used. The deformation or loading velocities differ as well. In a laboratory study comparative load and deformation controlled tests were run with different cement contents in the test cylinders (attaining strengths of f_k = 0.5 MPa, f_k > 3.5 MPa, and f_k > 13.5 MPa) and different rates of loading. For this particular series of tests at a given water-cement ratio, cement content, density and dimensions of the test cylinders) the test results do not reflect significant influence of the load type or load velocity to the measured compressive strength. For revised technical standards there should not be made requirements concerning load and deformation controlled tests. The rates of loading should be specified within clear ranges.