How Resiliency Impacts Concrete Design (ACI Fall 2020 Convention, Virtual Sessions) Building and infrastructure design is based upon safety provisions in building codes, engineering design standards, and industry expertise to meet its intended purpose and service life but fails to include fortification against extreme or progressive climate events. Sustainable, resilient design and construction minimize the risk of failure for buildings and infrastructure through enhanced robustness, durability, longevity, disaster resistance, and safety of structures. In conjunction with these principles, climate-adaption engineering provides hazard-resistant construction, retrofitting of existing buildings, and securing of building components. Adoption of these design and engineering measures are essential with regards to critical infrastructure. Sustainable, resilient design and climate-adaption engineering embrace the use of innovative materials and technology, sound construction practices, and employment of appropriate inspection and maintenance strategies. During this session, we will examine the available resiliency-based standards and resources and where standard adoptions seems to be heading.

Effects of Internal Curing Using Pre-Wetted Lightweight Aggregates on Durability and Service Life of Reinforced Concrete Structures (ACI Fall 2020 Convention, Virtual Sessions) The durability of concrete structures is generally improved through the use of internal curing (IC). IC concrete mixtures can increase the sustainability of concrete by reducing the drying and autogenous shrinkage cracking and improving the degree of hydration. Studies have been performed to assess the freeze-thaw performance of concrete mixtures. Work by Jones et al. demonstrated that concrete mixtures can be made resistant to freezing and thawing provided sufficient air entrainment was provided. Questions however have been raised as to whether the water released by the internal curing agents may increase the degree of saturation of concrete. A discussion will be made as to the role that internal curing may have on freeze-thaw damage at early ages. Guidance is provided as to the best approach for using internal curing including: 1) using concrete with a low water to cement ratio (w/c <0.42) and 2) curing times before the concrete is exposed to freezing are provided based on w/c. In conclusion, internally cured concrete provides good freeze and thaw performance provided the guidance above is followed.