User-friendlier language, provisions on alkali-silica reactivity and the absence of default requirements for slump are three of the changes in the latest update of ACI 301-16 Specifications for Structural Concrete, according to the American Concrete Institute. ACI released the document, along with the ACI Field Reference Manual, late last month. The update renders the widely used spec more designer- and contractor-friendly by removing language that was confusing or subject to interpretation, says Michelle Wilson, chair of the ACI 301-16 committee. The specifications cover virtually all forms of structural concrete used in construction. These include construction requirements for cast-in-place concrete, slabs on grade, architectural concrete, lightweight mass concrete, post-tensioned concrete, shrinkage-compensating concrete, industrial floor slabs, tilt-up concrete construction, and precast structural and architectural concrete. In addition, ACI 301-16 complements the reorganized ACI 318-14 Building Code Requirements for Structural Concrete.