This paper presents the physical, mechanical, and durability characterization of Tokyo Rope carbon fiber composite cables (CFCCs). Specimens were exposed to and alkaline solution (12.8 pH) for 1,000, 3,000, 5,000, and 7,000 h at different elevated exposure temperatures (22, 40, 50, and 60°C) to yield a simulated acceleration of the effect of a concrete environment. The durability performance of the Tokyo Rope CFCC tendons was assessed by conducting tensile tests on the specimens after different exposure periods. In addition, the microstructure of the CFCCs—both conditioned and unconditioned specimens—was investigated with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) to assess any changes or degradation. The preexposure and postexposure tensile strengths of the conditioned and unconditioned specimens were used for long-term behavior/performance predictions based on the Arrhenius theory. The test results revealed that the average tensile strength retentions o...

This paper aims to investigate the effect of fine recycled concrete powder (FRCP) on the strength of self-compacting concrete (SCC). For this purpose, a numerical artificial neural network (ANN) model was developed for strength prediction of SCC incorporating FRCP. At first, 240 experimental data sets were selected from the literature to develop the model. Approximately 60% of the database was used for training, 20% for testing, and the remaining 20% for the validation step. Model inputs included binder content, water/binder ratio, recycled concrete aggregates’ (RCA) content, percentage of supplementary cementitious materials (fly ash), amount of FRCP, and curing time. The model provided reliable results with mean square error (MSE) and regression values of 0.01 and 0.97, respectively. Additionally, to further validate the model, four experimental recycled self-compacting concrete (RSCC) samples were tested experimentally, and their properties were used as unseen data to the model. The results showed that the developed model can predict the compressive strength of RSCC with high accuracy.

Marine, coastal structures, and bridges deteriorate prematurely due to corrosion. Numerous failures have occurred in substructure members of these structures, such as piles, leading to very high repair and replacement costs. Problems related to corrosion could be resolved through the use of noncorroding materials such as fiber-reinforced polymer (FRP) bars. This paper presents the design, construction details, driving test procedures, and results of the field dynamic driving testing of precast glass-FRP (GFRP) reinforced concrete (RC) piles, as well as laboratory test results, to determine the piles flexural strength. Four piles were longitudinally and transversally reinforced with GFRP bars, spirals, and ties. Two of the piles were 6.0 m (approximately 20 ft) long, were fabricated, instrumented, and were laboratory tested for flexural strength. The other two piles were 18.0 m (approximately 60 ft) in length, were field installed and dynamically monitored. They were driven and monitored at the Arthur Drive Bridge project site in Lynn Haven, Panama City, Florida. Pile driving and testing were performed with a Vulcan 512 single-acting air hammer. The embedded data collectors (EDCs) were used to monitor the piles during driving operations. Field driving observations and results indicate that no pile damage occurred during installation. GFRP spirals successfully confined the concrete core of the piles and prevented cover spalling during driving. The maximum tensile and compressive stresses measured in the piles were well within the allowable design limits. Design aids and recommendations for good driving practices for GFRP-RC piles were presented. The promising results presented for the driven precast GFRP-RC piles represent a further step toward field application.

Many bridges are subject to lateral damage for their girders due to impact by over-height vehicles collision. In this study, the optimum configurations of carbon fiber reinforced polymers (CFRP) laminates were investigated to repair the laterally damaged prestressed concrete (PS) bridge girders. Experimental and analytical investigations were conducted to study the flexural behavior of 13 half-scale AASHTO type II PS girders under both static and fatigue loading. Lateral impact damage due to vehicle collision was simulated by sawing through the concrete of the bottom flange and slicing through one of the prestressing strands. The damaged concrete was repaired and CFRP systems (longitudinal soffit laminates and evenly spaced transverse U-wraps) were applied to restore the original flexural capacity and mitigate debonding of soffit CFRP longitudinal laminates. In addition to the static load tests for ten girders, three more girders were tested under fatigue loading cycles to investigate the behavior under simulated traffic conditions. Measurements of the applied load, the deflection at five different locations, strains along the cross-section height at mid-span, and multiple strains longitudinally along the bottom soffit were recorded. The study investigated and recommended the proper CFRP repair design in terms of the CFRP longitudinal layers and U-wrapping spacing to obtain flexural capacity improvement and desired failure modes for the repaired girders. Test results showed that with proper detailing, CFRP systems can be designed to restore the lost flexural capacity, sustain the fatigue load cycles, and maintain the desired failure mode.

This paper presents the analytical and experimental investigations performed to evaluate the structural behavior of Fiber-Reinforced Polymer (FRP) Honeycomb Sandwich Panels (HCSPs) used for bridge decks. The analytical investigation includes modeling FRP HCSPs using three Finite Element Models (FEM) and a simplified I-beam model. Comparing analysis results of the four models against experimental data from literature indicated that the simplified I-beam modeling method provides comparable accuracy while being computationally efficient. The experimental investigation includes flexure, creep, and fatigue testing of three full-scale HCSPs. Flexure testing was performed to estimate the linear stiffness and flexural capacity of the panel for calibrating the developed analytical models. Creep testing was performed by monitoring the panel behavior under sustained load for a six-month period using a wireless sensor system. Creep test results indicated that FRP HCSPs have insignificant creep deformations under service loads and room temperature. Fatigue testing performed for two-million cycles indicated that FRP HCSPs have adequate resistance to cyclic loads. On the other hand, static load testing of the fatigued panel showed a significant decrease in the panel stiffness.

This paper presents the results from an investigation into the performance of concrete bridge decks designed with the empirical design method. Compressive membrane/arching action (CMAA) behavior in bridge decks has been known for many years and has been adopted in design codes by some countries. AASHTO LRFD Bridge Design Specifications have provisions that allow the use of the empirical deck design method, which is based on CMAA. Despite the savings in deck reinforcement that the empirical method offers compared with the traditional method, the majority of state departments of transportation (DOTs) do not allow the use of the empirical method. In part, this is due to the fact that some of the current method limitations (e.g., lack of sufficient overhang length) are impossible to satisfy in phased construction and future widening scenarios. In this study, the performance of concrete bridge decks designed with the empirical design method was investigated through extensive experimental testing of a full-size specimen. The fabricated deck specimen mimicked a widening scenario, where the deck was supported on two prestressed concrete Florida I-Beams. Nine tests were conducted at different locations along the bridge deck under service and failure load levels. The results show that deck slabs designed according to the empirical design method are capable of meeting AASHTO LRFD serviceability and strength requirements. The outcome of this research study provides information to DOT officials regarding the feasibility of using the empirical method for the design of bridge decks under conditions not currently covered by AASHTO LRFD provisions.