Yes / The flexural performance of geopolymer concrete (GPC) T-beams reinforced longitudinally with GFRP bars under a four-point static bending test was investigated. Six full-scale simply supported T-beams were cast and tested; one control specimen was made with ordinary Portland cement concrete (OPCC), while the other five beams were made of geopolymer concrete. The G-GPC2 was designed to attain the same theoretical moment capacity as the G-OPCC6 control beam. The main parameters investigated were the reinforcement ratio of ρ_f/ρ_b= 0.75, 1.05, 1.12, 1.34 and 1.34 for G-GPC1, G-GPC2, G-GPC3, G-GPC4, and G-GPC5, respectively, and compressive strength of geopolymer concrete. Based on the results of the experiments, the ultimate strain of GPC did not show the same behaviour as that of OPCC, which affects the mode of failure. The beam capacity and deflection were, respectively, overestimated and underestimated using the ACI 440 2R-17 predictive equations.

The Construction sector is one of the biggest contributors to climate change. During 2020 the sector was responsible for 20% out of Sweden's total emitted greenhouse gases. The choice of construction materials is one of the key factors that decides a building’s or facility’s carbon footprint. The purpose of this paper is to research if Fiber Reinforced Polymer (FRP) can be a viable option to conventional steel reinforcement. The aim of this work is to find an answer to the following question “What is it that prevents us in Sweden from using FRP reinforcement in concrete?”. We have carried out calculations on a simple reinforced Concrete Beam and a reinforced concrete wall with different rebars (steel and FRP) according to Eurocode to assess the reliability of using FRP in concrete. The part of the study where carbon footprint is analyzed derives from two Environmental Product Declarations (EPD). The product Combar is one type of fiber reinforced polymer and represents FRP in this study. The steel reinforcement is represented by K500C-T. Results indicate that Combar can be a good alternative to steel with the right circumstances. The lack of standard and high carbon footprint are the two main factors which limits the use of FRP at the moment.During 2023 the goal for the European Commission for standardization is to release updated standards that include a calculation process for FRP. With the upcoming release of the new standard, our thesis is that FRP will get a wider range of use in Sweden. This is because a new standard will help the industry to be more aware of the benefits of using FRP

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A fiber reinforced polymer (FRP) composite cellular deck system was used to rehabilitate a historical cast iron thru-truss structure (Hawthorne St. Bridge in Covington, Virginia). This research seeks to address following technical needs and questions to advance FRP deck application. The critical panel-to-panel connections were developed and evolved through a four-stage study and finally realized using full width, adhesively bonded tongue and groove splices with scarfed edges. Extensive experimental study under service, strength and fatigue loads in a full-scale two-bay mock-up test and a field test was performed. Test results showed that no crack initiated in the joints under service load and no significant change in stiffness or strength of the joint occurred after 3,000,000 cycles of fatigue loading. Various issues related to constructability of FRP deck systems were investigated and construction guidelines and installation procedures for the deck system were established. The structural performance of the FRP-on-steel-superstructure system was examined in the laboratory and field under service load. Tests results confirmed the following findings: (1) the clip-type of panel-to-stringer connection provides little composite action as expected, which fulfilled the design intention; (2) local effects play an important role in the performance of FRP deck; (3) the FRP deck design is stiffness driven rather than strength driven like traditional concrete deck. Finally, an FEM parametric study was conducted to examine two important design issues concerning the FRP decks, namely deck relative deflection and LDF of supporting steel girders. Results from both FEM and experiments show that the strip method specified in AASHTO LRFD specification (AASHTO 2004) as an approximate method of analysis can also be applied to unconventional FRP decks as a practical method. However, different strip width equations have to be determined by either FEM or experimental methods for different types of FRP decks. In this study, one such an equation has been derived for the Strongwell deck. In addition, the AASHTO LDF equations for glued laminated timber decks on steel stringers provide good estimations of LDFs for FRP-deck-on-steel-girder bridges. The lever rule can be used as an appropriately conservative design method to predict the LDFs of FRP-deck-on-steel-girder bridges. / Ph. D.

The primary objective of this research was to investigate the shear strength of concrete bridge decks with GFRP top-mat reinforcement. Several models currently exist to predict the shear strength during the design process; however, previous research at Virginia Tech indicates that the existing equations are overly conservative. For this research, a series of concrete decks with varying lengths were tested in a laboratory environment in a two-span continuous configuration, during which data was collected on deflections, rebar strain, crack widths, and ultimate load. It was concluded that the existing equations, particularly the guidelines of ACI 440, are grossly over-conservative for GFRP-reinforced concrete bridge decks continuous over multiple supports. It was suggested that this is due to multiple factors, including additional support provided by the typically-neglected steel reinforcement in the bottom mat and a higher shear strength of the uncracked portion of concrete due to higher compressive stresses in the section as a result of the continuous deck configuration. The second objective of this research was to investigate the effects of environmental exposure on the composite deck and the individual GFRP rebar. Three deck specimens were subjected to differing environmental conditions, including one that was placed into service at an interstate weigh station. All three decks were tested in the same manner as those in the shear investigation. Additionally, live load tests were conducted on the weigh station deck during the time it was in place and tensile tests were conducted on rebar that were extracted from the concrete decks. In the live load testing, the GFRP strains increased by more than 200% over the period of service, which was likely due to a combination of a reduction in GFRP stiffness and a greater amount of cracking. During the laboratory tests on the decks, no clear correlation between conditioning and deflections or cracking was found. The ultimate strength actually increased with conditioning, with the weigh station specimen exhibiting the highest shear strength. Finally, the results of the rebar tensile tests suggested a decrease in both modulus of elasticity and ultimate tensile strength of the GFRP with environmental exposure when compared to unconditioned bars. / Master of Science

The purpose of this research was to investigate the effectiveness and durability of GFRP bars as reinforcement for concrete decks. Today's rapid bridge deck deterioration is calling for a replacement for steel reinforcement. The advantages of GFRP such as its high tensile strength, light weight, and resistance to corrosion make it an attractive alternative to steel. The first objective of this research was to perform live load testing on a bridge deck reinforced with GFRP in one span and steel in the other. The results were compared to the findings from the initial testing performed one year earlier. The strains and deflections of the bridge deck were recorded and the two spans compared. Transverse stresses in the GFRP bars, girder distribution factors, and dynamic load allowances were calculated for both spans. From the live load tests, it was concluded that the GFRP-reinforced span results were within design parameters. The only concern was the increased impact factor values. The second objective was to perform live load tests on a slab reinforced with GFRP installed at a weigh station. Two live load tests were performed approximately five months apart. Peak strains in the GFRP and steel bars were recorded and compared. The peak stresses had increased over time but were within design allowable stress limits. The third objective of this research was to investigate the long term behavior and durability of the GFRP reinforcing bars cast in a concrete deck. The strain gauges, vibrating wire gauges, and thermocouples in the bridge deck were monitored for approximately one year using a permanent data acquisition system. Daily, monthly, and long term fluctuations in temperature and stresses were examined. It was concluded that the vibrating wire gauges were more reliable than the electrical resistance strain gauges. It was further observed that the main influence over strain changes was temperature fluctuations. / Master of Science