A compression test for concrete-mortar-concrete specimens has been developed to investigate the compression behavior of the joint mortar between two ultra-high-strength precast concrete columns. A method for estimating the compressive strength from the strength values of constituent materials is proposed. Long-term loading tests confirmed that the joint mortar remains stable over a long period of time even under high stress. The compression test was also used as a joint mortar strength control test for a practical building. The test results indicate that the newly developed test can be used to obtain reliable strength test results under accuracy conditions of specimen fabrication and precise loading.

A compression test for concrete-mortar-concrete specimens has been developed to investigate the compression behavior of the joint mortar between two ultra-high-strength precast concrete columns. A method for estimating the compressive strength from the strength values of constituent materials is proposed. Long-term loading tests confirmed that the joint mortar remains stable over a long period of time even under high stress. The compression test was also used as a joint mortar strength control test for a practical building. The test results indicate that the newly developed test can be used to obtain reliable strength test results under accuracy conditions of specimen fabrication and precise loading.