Fireproofing deterioration is widespread in industrial facilities throughout the country. Spalling concrete has potential to damage equipment and harm personnel. Replacing concrete fireproofing like-in-kind, without consideration for proper anchorage or material durability, does not eliminate the hazard as spalls may potentially occur again over time. However, when properly designed and installed, concrete is a durable option for replacing deficient fireproofing in aggressive environments typically present in industrial processing units. This paper presents the results of a case study on a structure in a Midwest industrial complex. Extensive concrete fireproofing repairs were performed on the structure 12 years ago. Design requirements included normal weight concrete with polypropylene fibers which enhance durability by improving cracking resistance. During a fire, the fibers melt forming relief channels for moisture to escape, thus eliminating explosive spalling. Installation methods included welded wire reinforcement (WWR) with positive anchorage to structural steel. WWR was attached to post-installed adhesive anchors between column flanges where existing fireproofing was sound and difficult to remove. After 12 years in service, repairs exhibit no significant defects. This level of durability is attributed to the design and installation methods utilized. Concrete fireproofing is a durable option for fire protection, provided structures are designed to support its weight, its mixture design is properly proportioned, and it is adequately anchored and reinforced.

Ultra-high performance concrete (UHPC) is a novel material which shows impressive properties including high strength, increased toughness and excellent durability. One of the potential applications of UHPC is in heavily-loaded beams and bridge girders where their use can allow for more efficient design sections and increased durability. On the other hand, the high bond capacity of UHPC can eventually lead to brittle bar fracture failures in flexural members, especially when combined with low or moderate amounts of ordinary steel reinforcement (ρ ≤ 1%). This paper examines the influence of reinforcement grade on the flexural behaviour of UHPC beams. As part of the study, a series of UHPC beams built with either Grade 400 MPa ordinary steel reinforcement, Grade 690 MPa high-strength reinforcement or Grade 520 MPa stainless steel reinforcement are tested under four-point bending. The main parameters investigated include the influence of UHPC, steel type and tension steel ratio. Overall the results show that the ductility of the UHPC beams is influenced by both the tension steel ratio and steel grade/type. The results also show the benefits of combining UHPC with higher grade or higher ductility steel reinforcement.

Fiber Reinforced (FR) composites have become increasingly popular as retrofit solutions for buildings and infrastructure due to their ease of application, lightweight properties, and corrosion resistance. However, there are still research needs in this area that hinder wider adoption of fiber reinforced polymers (FRP) retrofit solutions and limit the understanding of initial and long-term performance of FRP-retrofitted components and structures. This paper presents the findings of an extensive literature review conducted by the authors to identify the state-of-the-art of FR composites, FRP-retrofitted structures and infrastructure, and guidelines and standards that address the testing, evaluation, and design of these systems. Research needs for FRP composites identified during a National Institute of Standards and Technology (NIST) workshop that convened a group of experts in industry, academia, and manufacturing are discussed. An overview of those research needs that received the highest ranking in this workshop are presented in this paper. Implementation of these ranked research needs by the FR composite research community, including NIST, will serve to impact and advance the field of FRP retrofit of buildings and infrastructure.

This paper presents a preliminary study on the durability of a bridge column under typical marine environments consisting of atmospheric, splash, and submerged conditions. To predict the migration of chlorides across the column, a simulation is conducted using a mathematical method, called cellular automata. Because chloride concentrations and the corrosion current density at the surface level of reinforcing steel can lead to the deterioration of a column over 100 years, they are of particular interest. The highest chloride concentrations are observed under the splash exposure, followed by the submerged and atmospheric conditions.

Durability is one of the most important requirements for built-environments. Federal, state, and local agencies expend significant effort to maintain the quality and condition of aging civil infrastructure, especially in aggressive service environments. Among many factors, durability influences the service life, integrity, and reliability of concrete materials and structures. Extensive research has been conducted to understand the deterioration mechanisms of concrete in an effort to extend the longevity of concrete members. This Special Publication (SP) contains nine papers selected from three technical sessions held during the virtual ACI Fall Convention in October 2021. Emphasis is placed on durable reinforcing schemes, service life prediction, structural integrity, repair and retrofit, corrosion mitigation, inspection techniques, and the application of state-of-the-art construction materials. All manuscripts were reviewed by at least two experts in accordance with the ACI publication policy. The Editors wish to thank all contributing authors and anonymous reviewers for their rigorous efforts. The Editors also gratefully acknowledge Ms. Barbara Coleman at ACI for her knowledgeable guidance.