Life Cycle Lessons Learned: A Mile-Long 60-Year-Old Bridge over a Water Body
Presented By: Mohammad Khan
Affiliation: High Performance Technologies Inc.
Description: This paper presents the life cycle lessons learned from the investigation of a mile-long 60-year-old bridge over Tennessee River. The bridge was constructed in 1964, has exceeded its design life of 60 years, and has shown presence or absence of various forms of deterioration. For example, the chloride contamination in the piers of the bridge, both above and below water, was significantly lower than the threshold chloride ion content required to initiate and propagate reinforcing steel corrosion, and no significant level of corrosion of reinforcing steel was observed in the piers of the bridge. On the other hand, the piers of the bridge have shown evidence of alkali-silica reaction (ASR) which has progressed over the years and has contributed to the overall deterioration of the piers. The bridge is slated to be replaced within the next few years. The investigation of this bridge and the lessons learned highlight the importance of a holistic consideration of all the deterioration mechanisms in the light of materials being used and the exposure conditions the concrete structures are subjected to during their life cycle
Enhancing Concrete Durability and Sustainability with Lightweight Aggregates for Extended Service Life
Presented By: Fariborz Tehrani
Affiliation:
Description: Extending the service life of concrete structures is critical to reducing lifecycle environmental impacts and improving long-term performance. This study investigates the use of lightweight aggregates (LWAs) as a strategy to enhance concrete durability, particularly in mitigating chloride ion ingress—a primary factor in the corrosion of embedded steel reinforcement. The research evaluates the influence of LWA on concrete permeability, pore structure refinement, and resistance to chloride penetration from external sources such as seawater and de-icing salts. Experimental results demonstrate that LWA-modified concrete exhibits improved resistance to chloride-induced corrosion, both in terms of delayed initiation and reduced propagation rates. These findings support the integration of LWAs into sustainable design practices for new and existing concrete structures, offering a technically viable approach to extending service life while contributing to environmental and economic footprints reductions across the built environment.
Comparative Sustainability, LCA and Service Life Modeling for Repair vs. Rebuild – A Case Study
Presented By: Eric Samson
Affiliation: SIMCO Technologies
Description: Concrete is a durable, energy-efficient, and adaptable material. When properly designed, maintained, and repaired, its initially high embodied carbon footprint can be significantly mitigated. One of P+Ex’s strategic goals is to promote sustainable concrete asset management by conserving natural resources and minimizing environmental impact. This case study examines a real-world parking garage repair project using standardized scientific methods to compare the extended service life and its carbon footprint achieved through repair versus full replacement, offering insights into sustainable decision-making in infrastructure management
Service Life Extension of Toronto’s Gardiner Expressway
Presented By: David Whitmore
Affiliation: Vector Corrosion Technologies Ltd.
Description: After more than 50 years of service, the 6.8-km elevated Gardiner Expressway in Toronto has experienced significant deterioration. Rather than opting for demolition or underground relocation, the City of Toronto launched the Gardiner Expressway Strategic Rehabilitation Plan. This initiative involves replacing the entire concrete deck and steel girders using accelerated bridge construction, while rehabilitating and protecting the existing substructures. To minimize commuter disruption, the substructures were structurally repaired using galvanic encasement technology, which is expected to provide corrosion protection for the next 30 to 40 years — extending the expressway’s service life and preserving critical infrastructure.
P+Ex – Preserve, Extend and Lead (Improving the Durability and Service Life of New and Existing Concrete Structures: 2 years into the P+Ex Journey
Presented By: Lesley Suz Chung Ko
Affiliation: Structural Technologies
Description: P+Ex is a non-profit center of excellence dedicated to enhancing the durability and service life of concrete structures. Its mission is to advance global awareness, education, tools, and actionable strategies that support a sustainable built environment. Since its launch in Spring 2024, P+Ex has hosted a series of road-mapping workshops with industry experts to define aspirational goals and strategic objectives. The organization’s strategic plan is now in motion, with initiatives underway to quantify the societal and financial benefits of service life extension and demonstrate the environmental advantages of concrete repair over replacement.
Combating Corrosion of Rebar in Cracked and Uncracked Concrete Exposed to Air Borne Chlorides, Seawater and Road Salts
Presented By: Philip Rhodes
Affiliation: Hycrete Inc.
Description: Different methods for limiting corrosion of rebar in both untracked and pre-cracked concrete will be discussed. The depth of chloride penetration in bridge decks after 3 years exposure in the Mid-Atlantic, corrosion rates in 15% salt water with repeated soaking and drying cycles for concrete containing different anti-corrosion agents, C1556 chloride diffusion rates and the corrosion of metals per ASTM D1384 will be shared. Finally, USACE Life 365 studies on air -borne chlorides at different distances from the coast in warm coastal areas will be presented.
Durability of Portland Limestone Cement Concrete
Presented By: Ali Inceefe
Affiliation: Tourney Consulting Group, LLC
Description: Portland Limestone Cements Type IL (PLC) are seeing increased use in North America. They reduce the carbon footprint of ordinary portland cement (OPC) by replacing 5-15% of the clinker with limestone. The high-quality limestone is added into the mill and therefore these cements result in a wider Particle Size Distribution (PSD) with a finer size fraction. A major project in the Northwestern United States had performance properties based on Type I-II cement which was not going to be available. This paper shows that PLC when used with ASTM Class F fly ash or slag cement can meet concrete permeability and freezing and thawing resistance parameters required for exposures to chlorides and freezing and thawing. The data obtained were from actual project concrete mixes produced with a large laboratory mixer, and the project proceeded with the Type IL replacement for Type I-II.