| The current acceptance criteria for structural masonry in accordance with International Building Code allows for the prism test method to be used. However, without a proper understanding of the effects of variable material properties such as individual masonry unit compressive strength and the various material moduli of elasticity, as well as the effect of field conditions on the unit's performance, masonry prisms may "fail" to reach the design compressive strength (f'm).;By identifying causes of failure and evaluating the failure magnitude, it is concluded that when the masonry prism test method is utilized for acceptance testing of as-built masonry structures, additional testing should be performed on the grout in order to fully understand the influence that grout strength and possible grout deformation on the concrete masonry unit during the uniaxial compression test. If grout and block characteristics indicate it is appropriate, some combination of the unit test method and the prism test method may be appropriate to provide a determining reliability of test result implications. Alternatively, a complete re-evaluation of the prism test method and its applicability to acceptance criteria for structural masonry may be appropriate. |
