Architectural concrete is a highly desired architectural finish throughout the world. However, a lack of understanding of the design and construction requirements often allows water intrusion. To be successful with architectural concrete, structural engineers, architects, and contractors must work in tandem to provide the required structural and waterproofing performance while achieving the desired aesthetic finish.
This article focuses on factors within the design and construction process that affect the serviceability, impermeability, and appearance of architectural concrete, and lays out strategies to improve performance. Part 1 covers design and specification. In the April issue, Part 2 will cover construction techniques and reparability.
Architectural concrete will be permanently exposed to view. Therefore, it requires special care in the selection of materials and in forming, placing, and finishing techniques to get the desired appearance and performance. In addition to the typical structural requirements of strength and serviceability, architectural concrete must also maintain the desired aesthetic appearance and be watertight. The concrete is acting as a barrier wall and is the only line of defense against water intrusion.
The appearance of architectural concrete is a function of the specified characteristics such as color and texture. However, if not properly designed and placed, the appearance and serviceability can be impacted by finish inconsistencies, cracking, and excessive deflections or deformations. If architectural concrete is not designed to prevent water intrusion, the result can be damage to the structural elements of the wall and interior finishes, and possibly biological growth within the wall assembly.
Designing and specifying architectural concrete involves the mix design, possible inclusion of admixtures, design of steel reinforcement, specification and layout of control joints, design to limit deflections, and design for reparability.