International Concrete Abstracts Portal

Coastal reinforced concrete bridges are critical infrastructures, yet they face significant threats from corrosion due to saline environments and extreme loads like wave-induced forces and seismic events. This state-of-the-art review examines the resilience of corrosion-damaged RC bridges under such conditions. It compiles advanced methodologies and technological innovations to assess and enhance durability and safety. Key highlights include synthesizing loss estimation models with advanced reliability methods for a robust resilience assessment framework. Analyzing catastrophic bridge failures and environmental deterioration, the review underscores the urgent need for innovative materials and protective technologies. It emphasizes advanced analytical models like Performance-Based Earthquake Engineering (PBEE) and Incremental Dynamic Analysis (IDA) to evaluate combined impacts. The findings advocate for engineered cementitious composites (ECC) and advanced sensor systems for improved real-time monitoring and resilience. Future research should focus on developing comprehensive resilience models accounting for corrosion, seismic, and wave-induced loads to enhance infrastructure safety and sustainability.

Corrosion of steel anchors in concrete poses a significant risk, leading to detachment, structural damage, and loss of anchor strength. To enhance the durability of structural elements involving anchors, the use of corrosion-resistant nonmetallic inserts could be a feasible alternative. This study presents an experimental investigation of the tensile and shear concrete breakout strength of a single cast-in fine ceramics insert (FCI). The tensile tests were conducted with FCIs located at the center and edge of concrete blocks, while the shear tests were conducted with inserts positioned at varying distances from the concrete block’s edge. The experimental program comprised 75 specimens of three different FCI diameters (FCI 1/2 in. [12.7 mm], FCI 5/8 in. [16.0 mm], and FCI 1 in. [25.4 mm]) with two different embedment depths for each type. The experimental results showed that FCI anchors performed satisfactorily, providing bearing capacity conservatively satisfying the values calculated by ACI equations for the concrete breakout strength.

This study characterized pitting corrosion in prestressed piles, links it to stress concentration factors via ultimate strength tests, and finally incorporates the findings into a simple predictive damage assessment model. Six 1/3 scale Class V concrete prestressed piles were exposed for 38 months to outdoor tidal cycles simulating a marine environment. At exposure end, 24 strands were extracted from the piles, and the corrosion loss along the strands was quantified using a new Pascal’s law-based strand profiler. This identified regions of locally higher steel loss caused by pitting corrosion. The same data set was used to confirm gravimetric loss measurements by summing localized section losses over the specimen length. Profiler data was complemented by microscopic imaging to further define pitting geometry. Ultimate load tests were conducted to examine the effect of pitting on residual tensile strength and ductility. Similitude principles were used to show how the results can be used to predict the state of in-service pile strands where only inspection report crack widths are required.

Titanium alloy bars (TiABs) have recently been accepted as a structural material for near-surface mounted retrofit (NSMR) of reinforced concrete structural elements. This paper shows that TiABs in NSMR applications can be used simultaneously as anodes in impressed current cathodic protection (ICCP) to prevent corrosion of the existing reinforcement. Following a successful proof-of-concept study performed for small-scale prisms, dual-purpose TiABs were used as longitudinal and shear reinforcements to retrofit large-size structural beams. Prior to structural tests, the specimens were investigated to characterize the TiAB functionality within the ICCP system. During ICCP, cathodic potentials were in the expected linear region of the cathodic polarization curve of the steel rebars, and the 100-mV potential shift (decay) criterion following shut-off was satisfied upon the interruption of the protection current. The applied current and potential to achieve the required cathodic potentials were stable and were satisfactorily maintained while achieving the structural retrofit requirements.

Pourbacks and overlays are commonly used in bridge elements and repairs, as it is crucial to corrosion protection that the bond between grout and concrete in these regions is carefully constructed. The integrity of the bond is crucial to ensure a barrier against water, chloride ions, moisture, and contaminants; bond failure can compromise the durability of concrete structures’ long-term performance. This study examines the influence of surface preparation methods on the bond durability and chloride permeability between concrete substrate and grouts, including both non-shrink cementitious and epoxy grouts. A microstructural analysis of scanning electron microscopic (SEM) images was conducted to characterize the porosity of specimen interfaces. Pulloff testing was performed to quantify tensile strength. Results show that a water-blasted surface preparation technique improved the tensile bond strength for cementitious grout interfaces and reduced porosity at the interface. In contrast, epoxy grout interfaces were less affected by surface preparation. The study establishes a relationship between chloride ion permeability, porosity, and bond strength. The findings highlight the importance of surface preparation in ensuring the durability of concrete-grout interfaces.