Specification in Practice

摘要

The typical clause incorporated in specifications from i the AIA MasterSpec (2014) is: Cementitious Materials: [Limit percentage, by weight, of cementitious materials other than portland cement in concrete as follows:] 1. Fly Ash: 25 percent. 2. Combined Fly Ash and Pozzolan: 25 percent. 3. Slag Cement: 50 percent. 4. Silica Fume: 10 percent... The MasterSpec (2014) notes inform the designer that j this clause is used for concrete exposed to freezing j and thawing cycles and the application of deicing salts. However, this advice seems to be ignored by specification writers. In an NRMCA review of more than 100 specifications for private work, these limits were noted in 85% of the specifications, without consideration of the anticipated exposure condition for concrete members. Some specifications specifically prohibit the use of supplementary cementitious materials (SCMs).