FREEZE-THAW DURABILITY OF HIGH-PERFORMANCE CONCRETE MASONRY UNITS
A high-performance concrete masonry unit (CMU) was developed to replace the standard 38-lb (17.2-kg) unit used in modern construction. High-performance units were produced from several different trial mixes. This paper presents the results of tests conducted to determine the durability of the new units as compared to standard normal-weight CMUs. The units were tested for absorption and for freeze-thaw durability. High-performance units that were made with normal-weight aggregates had somewhat lower absorption rates than standard units, but the freeze-thaw durability was reduced. High-performance units produced with lightweight aggregates had absorption results comparable to standard normal-weight units. The freeze-thaw durability of these units varied, and for some, it was superior to that of standard normal-weight units. Admixtures were used in some mixes to increase durability and lower absorption. A lightweight mix that used a waterproofing admixture to precoat the aggregate before mixing resulted in the most durable units under freeze-thaw testing. These units also had very low absorption rates.