By Claude Goguen, P.E., LEED AP
As the precast concrete industry continues to evolve, the diversity of product lines continues to grow. The National Precast Concrete Association’s Plant Certification Program is part of this dynamic industry evolution and continues to adapt to meet member needs. To address the growth in the architectural precast sector, NPCA has added new content to its Quality Control Manual for Precast and Prestressed Concrete. Most of the architectural content will be found in Chapter 4 – Production Practices; however additional information related to architectural precast has been added throughout the manual. The process of furnishing fabrication drawings and mock-ups can be found in Chapter 1 – General, for example.
Chapter 2 – Materials contains additional requirements related to architectural finishes such as: using the same type and brand of cement from the same mill and lot to avoid color variations; and avoiding mix water with iron oxides to prevent staining when using white cement.
Chapter 3 – Concrete contains requirements for producing a piece with different mix designs for face and back-up concrete.
Requirements and recommendations for all different types of surface finishes such as exposed aggregate, acid-etched, stone or clay veneers are contained in Chapter 4. The application of surface retarders, the use of tools in finishing architectural concrete and the use of bond breakers when producing products with stone veneers are examples of additions to this chapter.
The NPCA Building Committee and its subcommittees are already hard at work developing additional architectural precast content for the next edition of the manual. Members and staff will continue to add and refine content so that it continually serves the evolving needs of our membership as well as the needs of industry specifiers.
Claude Goguen, P.E., LEED AP, is NPCA’s director of Technical Services.