It is important to note that these web configuration changes do not require any change to web configurations or unit properties-most traditional two-cell concrete masonry units still comply with ASTM C90.Īllowing the option to reduce the web thickness and/ or area allows for a greater array of unit configurations. Under new C90 requirements, web configurations are no longer regulated by their thickness, but rather the cross-sectional area of the web connecting the face shells of a unit. In 2011, C90 was modified to permit the cross webs of units to be configured in different ways to meet specific project needs and performance requirements. ASTM C90 contains minimum requirements that assure properties necessary for quality performance, including specified constituent materials, minimum face shell and web thicknesses, minimum compressive strength, permissible variations in dimensions, and finish and appearance criteria.
The most widely-used standard for specifying concrete masonry units in the United States is ASTM C90, Standard Specification for Loadbearing Concrete Masonry Units (ref.