Concrete pavements are facing rapid deterioration due to the increasing high traffic volumes. Maintenance, rehabilitation and reconstruction (MRR) have become major activities for all the state highway agencies. Due to shortage of available funding and continuous aging of pavements, many state highway agencies are now seeking cost-effective MRR strategies. This has led a need to develop a systematic and comprehensive decision process for selecting the optimum MRR strategy that considers pavement, traffic and construction issues. This research is an effort to help the state highway agencies select the maintenance, rehabilitation and reconstruction strategy for concrete pavements. The research identifies feasibility, suitability and acceptability criteria that every MRR strategy should meet. The rehabilitation strategies satisfying these criteria are then weighed in decision process to determine the optimum rehabilitation strategy. Research also focuses on developing recommendations for statewide methods for rehabilitating jointed concrete pavements so as to minimize reflective cracking. Data was collected from relevant project case studies to assess and improve the framework for decision process. Further research will be required to enhance the selection process.

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Since concrete bridge deck slabs are much longer in the traffic direction, they experience transverse early-age cracks due to volumetric instability and restraint. In the last decade, the lower cost of the non-corrodible Glass Fiber Reinforced Polymer (GFRP) bars, as alternative to steel reinforcement, has made them attractive to the bridge construction industry. However, low modulus of GFRP bars may lead to wider cracks in GFRP-RC structures. This serviceability issue can be aggravated by harsh environmental conditions. Hence, the main objective of this thesis is to investigate the effect of early-age cracking in restraint bridge deck slabs reinforced with GFRP bars subjected to different environments. This research consists of two phases: an experimental investigation and a numerical study. In the experimental phase, four full-scale cast-in-place slabs reinforced with different longitudinal GFRP reinforcement ratios (0.30, 0.50, 0.70 and 1.1%) and one with steel reinforcement ratio of 0.7% measuring 2500 mm long × 765 mm wide × 180 mm thick were constructed and tested in the laboratory. Three environmental conditions were implemented; normal (laboratory) adiabatic conditions as well as freezing-thawing and wetting-drying cycles. The main test results are presented in terms of cracking pattern, width and spacing, and strains in the reinforcement and concrete. Test results indicated that the minimum reinforcement ratio (0.7%) recommended by CHBDC for bridge deck slabs reinforced with GFRP bars satisfied the serviceability requirements after being subjected to the simulated exposures of normal laboratory conditions, freezing-thawing, and wetting-drying cycles. In the numerical phase of this research, a finite element model (FEM) was constructed using ATENA software package (ver. 5) to simulate the behaviour of the test specimens. According to the FEM results, a reinforcement ratio of 0.45% Carbon FRP (CFRP) can control the early-age crack width and reinforcement strain in CFRP-RC members subjected to restrained shrinkage. Also, the results indicated that changing the bar surface texture (sand-coated and ribbed bars) or concrete cover had an insignificant effect on the early-age crack behavior of FRP-RC bridge deck slabs subjected to shrinkage. However, reducing bar spacing and concrete strength resulted in a decrease in crack width and reinforcement strain. / October 2015

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In the past few decades, several researchers have studied the effects of ASR induced expansion in concrete. Several models have been proposed to model the effects of ASR in concrete. While most of these models focus on plain concrete, there is limited amount of research to model the influence of ASR expansion in reinforced concrete. Additionally, the existing models are complex and difficult to implement for practicing engineers. In this study the shortcomings with the existing models are addressed. A minimalist semi-empirical model is developed to represent the degradation of reinforced concrete due to ASR expansion. The model is validated using historical experimental data. Only two key parameters are needed to represent the expansive behavior, specifically, the maximum unreinforced concrete strain due to ASR expansion and the rise time. Mechanical properties of the reinforced concrete are also needed. From the predicted expansions, it is then shown that it is possible to model the number and spacing of cracks of a partly restrained reinforced concrete beam affected by ASR gels. The model is validated with recent experimental results on large scale reinforced concrete specimens. Predictions agree well with the observed number of cracks.

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This research was undertaken to study the effects of high performance concrete (HPC) mix design modifications on the propensity of early-age cracking. Seven mixtures were tested: one 35 MPa conventional concrete (CC) mixture made with ordinary Portland cement with blended slag; one typical 50 MPa HPC mixture containing slag and silica fume; and five modified HPC mixtures using extra set-retarder, increased slag replacement, shrinkage-reducing admixture (SRA), pre-saturated lightweight aggregate (LWA), and decreased cement paste content to improve thermal and/or shrinkage properties. The mixtures were tested for durability, mechanical, thermal, and shrinkage properties. All modified HPC mixtures showed reduced shrinkage relative to the HPC control mixture, and the most shrinkage mitigation was observed in the mixture containing LWA. While SRA reduced restrained shrinkage in HPC to the magnitude of CC, it provided very low rapid chloride penetrability, and using LWA in HPC resulted in significant restrained shrinkage reduction compared to CC.