Evaluation of Poroton Masonry and Suggestion for Quick Design Procedure

Poroton masonry units are highly cored extruded clay units with numerous thin webs. They have ground surfaces and are laid on a thin fluid mortar bed, with no mortar in the head joints. They offer the advantages of quick construction, which can be performed by a general labor force.

This thesis describes the results of component and prism testing of Poroton masonry. Compressive strength tests occurred on individual units and on prisms constructed with two units in accordance with the manufacturer’s directions. The average unit compressive strength was approximately 2900 psi. The average prism compressive strength was about 900 psi. In addition to compressive testing on the two unit prisms, flexural strength testing was conducted on the prisms. During flexural strength testing, modifications to the flexural testing device, also known as the “Bond Wrench,” were made. These changes allowed a pure moment to be applied during flexural tension testing. The average flexural tensile strength for Poroton masonry was 65 psi.

With the strength properties now defined, a review of unreinforced and reinforced design methods applicable to the Poroton units have been made. For unreinforced design, conventional procedures can be used for Poroton construction. However, section properties can be approximately determined based on net moment of inertia of 60% of the gross moment of inertia. For reinforced design, an approximate method was developed. The approximate method is based on a simplified “T-beam” design that is commonly used for partially grouted walls. The distance from extreme compression fiber to the neutral axis was slightly modified to account for the unusual crosssectional geometry. This approximate reinforced design method tended to be slightly conservative when compared to an exact design method.