Adequate interfacial bond performance of Bonded Concrete Overlay (BCO) systems requires novel integration of material mixture design, compatibility model development, and interfacial bond design. This entails the use of the right materials, on the right substrate, in the right way, in order to secure the best possible composite behaviour. The overall composite performance of BCOs depends largely on achieving the right proportion of blend for the overlay material. The use of mixture experiments provides a flexible, easy, and quick way of optimizing multi-component materials of this nature. This study describes the use of optimization techniques within the concept of material mixture experiments for proportioning and designing the material constituents of a Bonded Roller Compacted Fibre Reinforced Polymer Modified Concrete (BRCFRPMC). By constraining the range of variability of the constituents, a feasible design space was created with 13 experimental points treated based on the required structural and elastic properties of the overlay. The optimum consistency-time for full consolidation and composite behaviour with the substrate ordinary Portland cement concrete (OPCC) was established between 34.05 and 34.87 seconds, while the resulting apparent maximum density achieves between 97.11% - 98.03% of the theoretical air-free density. In addition, compressive strength response at early and matured ages of 3 and 28 days were satisfied at 100% desirability. The elastic modulus response at age 3 showed 0% desirability, but attains about 99.96% of the target response by 28 days. The verification experiments conducted on each response property shows that positive correlations exist between the measured responses and the predicted values from the optimization analysis. Also, the bond capability of the optimum designed overlay material was evaluated using both tensile and shear bond strengths parameters. The overall assessment results showed that the overlay material exhibits good bonding with the substrate OPCC and would be able to withstand substantial stresses where sufficient surface texture is provided for aggregates interlocking. Other material properties included in the evaluation process of the overlay material included its tensile strength, coefficient of thermal expansion, and drying shrinkage. Stresses in the overlay, substrate, and at the interface were assessed analytically under various differential movement related conditions. Though the interface and the overlay material exhibited sufficient strength against thermal and shrinkage cracking, the theoretical shrinkage cracking in the overlay was predicted at 6.92MPa when fully restrained axially. Further, for effective fracture process description of the interface, experimentally determined parameters in shear and tension were coupled in Mixed-Mode Finite Element Analysis using differential edge deformation model between the overlay and the underlay. The results indicated that delamination in partial fracture process varied from that of complete fracture process, influenced distinctly and largely by the magnitude of the applied load. Other influencing factors in the analyses included the elastic mismatched properties, initial edge defect size, and the plane of loading. Lastly, analytical solution to the FEA problem was implemented using the proposed Modified Eigenvalue Buckling Analysis (MEBA). The result indicated that the proposed analytical method simulates and compares well with the FEA result. The proposed method also provided a good technique for predicting the Mixed-Mode Buckling failure Mode-Shape of the overlay.

Although the application of surface treatments on bridge decks is expected to positively impact bridge deck condition, the effectiveness of specific surface treatments on extending bridge deck life has not yet been quantified on Utah bridge decks. Therefore, the objectives of this research were to develop and analyze deterioration curves for bare concrete bridge decks and decks with specific treatments commonly used in Utah. The scope of this study was determined by the types and extent of electronically available data, including selected static inventory information; maintenance, rehabilitation, and reconstruction histories; and National Bridge Inventory (NBI) condition ratings for the bridge decks. Bridge deck selection criteria and analysis procedures were developed to enable evaluation of the effects of surface treatments on bridge decks in Utah. Characteristics of a typical bridge were defined, and a list of typical bridges was produced to minimize potentially confounding effects of atypical bridge characteristics in comparisons of deterioration curves for monolithic concrete decks, decks with a bituminous overlay, decks with an epoxy overlay, and decks with a latex-modified concrete overlay. Climatic differences were taken into account by grouping bridges not only by overlay type, but also by Utah Department of Transportation region, which was used in this research as a general surrogate for latitude. Individual bridge deck deterioration curves were then combined to generate average deterioration curves aligned by deck construction time and average deterioration curves aligned by deck treatment time. To at least partially account for the potentially different effects of different treatment times, the bridge groups involving overlays were divided into two treatment time categories, early and late, for analysis. The average deterioration curves aligned by deck construction time suggest that certain treatments applied at certain times can achieve average NBI ratings greater than those for monolithic concrete during selected years of bridge deck life. The average deterioration curves aligned by deck treatment time suggest that certain treatments applied at certain times can achieve improvements in NBI ratings that correspond to apparent increases in bridge deck service life. Primarily because the NBI rating system is based mainly on visual inspection, the full benefits of early applications of surface treatments are not apparent in the results of this research. Supplemental perspectives may be gained about the performance of specific surface treatments by evaluating bridge deck deterioration in terms of delamination, half-cell potential, and chloride concentration, for example, which are direct measures of the deterioration process typically experienced by concrete bridge decks in Utah.

This research project, funded by the Federal Highway Administration, entails the construction of an outdoor exposure site in order to evaluate various methods for mitigating alkali-silica reaction (ASR) in hardened concrete. The exposure site, built at the Concrete Durability Center at the University of Texas at Austin J.J. Pickle Research campus, included a series of bridge deck, column and slab elements. The specimens were cast in 2008, allowed to expand to predetermined expansion levels and then treated with various mitigation measures, after which the specimens were monitored for expansion, humidity, and deterioration. / text

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The target of the ‘Green Overlays’ research was a cost effective, minimal disruption, sustainable and environmentally friendly alternative to the wholesale demolition, removal and complete reconstruction of the existing structural concrete pavement. The important problem of flexural resistance for strengthening concrete pavements with structural overlays has been scrutinised. A new mix design method for steel fibre reinforced, roller compacted, polymer modified, bonded concrete overlay has been proposed. The mixes developed were characterized of high flexural strength and high bond strength with the old concrete substrate. ‘Placeability’ and ‘compactability’ of the mix were two dominant issues during laboratory investigation. An innovative approach for establishing the relationship between Stress and Crack Face Opening Displacement for steel fibre reinforced concrete beams under flexure was developed. In addition, a new and simple method for calculating the interfacial Strain Energy Release Rate of both, a two-dimensional specimen and a three-dimensional model of the overlay pavement system were developed. This method can be readily and easily used by practicing engineers. Finally, a new test specimen and its loading configuration for measuring interfacial fracture toughness for concrete overlay pavements were established. The interfacial fracture toughness of a composite concrete beam, consisted of steel fibre-reinforced roller compacted polymer modified concrete bonded on conventional concrete and undergoing flexure, was assessed. In summary, this thesis presents four key findings: A new mix design method for steel fibre-reinforced roller compacted polymer modified concrete bonded on conventional concrete. A new method for establishing the fibre bridging law by an inverse analysis approach. A new, simplified method for calculating strain energy release rate at the interface of a composite beam. A new, innovative technique for calculating strain energy release rate at the interface of an overlaid pavement. The thesis contains a plethora of graphs, data-tables, examples and formulae, suitable for future researchers.

This diploma thesis analyses behaviour of reinforced concrete slabs and their strengthened variants. Their comparison is determined by the results from the experimental load test. Outcomes are accompanied by the results gained from the analytical calculation according to valid codes and requirements and also nonlinear finite element method analysis.