Architects' Day Lunch (ACI Fall 2021 Convention, Virtual Sessions) Buildings alone account for 40% of the global greenhouse gas emissions. Two thirds of that total impact is from operational emissions while the remainder is from embodied emissions. Embodied emissions include all the emissions required to produce everything that goes into our buildings – the structure, enclosure and all the materials inside. Between now and 2050, half of the new construction emissions between now and then will be from embodied carbon. Therefore, the industry has begun to take action and groups like AIA 2030, Architecture 2030, SE2050, and USGBC have shifted their focus to include embodied carbon. In order to address this issue, we need to take steps to quantify and then reduce our impact. We can do this using a process called Whole Building Lifecycle Assessment (WBLCA). More and more project teams are using WBLCA as a design tool and are discussing decarbonizations strategies. As such, design professionals are actively and looking for low carbon material alternatives. Since cement is such a ubiquitous and carbon-intensive material, it is definitely at the center of these discussions. It’s important that the concrete industry be aware of what is being discussed in the market and how this will affect our industry in the future as this trend grows. This presentation will also look at examples of how this translates to the design documents, the specifications and ultimately the concrete mix designs.

Adapting and Reuse of Concrete Structures (ACI Fall 2021 Convention, Virtual Sessions) This presentation will introduce the concept of Tessellated Structural-Architecture (TeSA) systems and will describe an experimental test of a reinforced concrete TeSA shear wall. TeSA systems are comprised of individual tiles arranged in tessellations or repeating geometric patterns. Tiles are topologically interlocking, which means that they transfer forces by nature of their geometry rather than through a bonding adhesive or mechanical connection. A benefit of such a system is the ability to rapidly disassemble the tessellation and repurpose the tiles. Additionally, there is a potential benefit of localizing failure and rapidly repairing individual damaged tiles, rather than the entire system. In this manner, TeSA structures are sustainable due to the reuse of materials and resilient due to the ability for rapid repair. The TeSA concept is demonstrated through a test program involving reverse cyclic loading of the specimen. General load-displacement behavior, crack propagation, and energy dissipation will be discussed for virgin and repaired TeSA walls.