The objective of this dissertation is to explore various methods to enhance roadway and bridge infrastructure repair and performance through the development and understanding of new materials, durability and non-destructive testing methods, and design methods. The first objective is to develop a durable and resilient rapid repair patch material for typical, vertical, and overhead repairs. Three different rapid setting cements were used for the mixed formulations based on the NJDOT qualified product list. The addition 1% polyvinyl alcohol fibers (PVA) and 50% round pea gravel were also evaluated to improve the tensile strain capacity and self-compacting nature of the mix formulations. A total of twelve mix formulations were cast in field conditions on a porous slab and then replicated on a plain concrete slab to compare the effects of different levels of restraint by monitoring shrinkage crack development. These restrained shrinkage samples were monitored for two years to understand their long-term performance. At the end of the monitoring period, the restrained shrinkage samples underwent tensile bond strength testing using the pull-off method to evaluate the strength of the adhesion between the repair material and parent substrate. This experimental work provides insight into the overall performance of each of the mix formulations to assess their compatibility with the requirements for each of the three repair types. The second objective is to evaluate the accuracy and precision of non-destructive Schmidt hammer testing to provide a low-cost method of assessing the in-situ structural strength of concrete. The Schmidt rebound hammer is designed to provide a rebound number that correlates with a compressive strength based on the hardness of the concrete. This study aims to investigate the effects of different environmental factors such as age, surface saturation, and temperature on the Schmidt hammer rebound response. Another factor that is considered for this study is the rebound response of ultra-high performance concrete (UHPC) and latex modified concrete (LMC) which are commonly used for bridge decks and overlays. These materials have higher compressive strengths and denser matrices than normal weight concrete, which yields higher rebound numbers. The rebound numbers are collected, mapped, and compared, to understand the performance of the two different deck slabs to the Schmidt hammer’s sensitivity. The results show a difference between the mean round numbers of UHPC and LMC of roughly 10, with UHPC reporting higher average rebound values of approximately 44. This research will also evaluate the limitations of the Schmidt hammer to detect voids and delamination in concrete. There are currently limited studies that specify the maximum depth that the Schmidt hammer can detect defects in a concrete slab. Therefore, a concrete slab is cast with known artificial defects at varying depths and then tested with the Schmidt hammer. The results from the testing show that the Schmidt hammer can accurately detect defects at depths between 4 and 6.25 inches below the concrete surface and proposes further testing strategies to improve the analysis. By understanding the advantages and limitations of Schmidt hammer, better calibration models and rebound curves can be developed to increase the accuracy of the non-destructive test, reducing the cost and potential need for coring when maintaining bridges. The third objective of this research was to investigate applications and mechanical properties of hybrid UHPC-ferrocement material for infrastructure rehabilitation. The study evaluates the workability and flexural strength of UHPC-ferrocement with the inclusion glass, hooked end steel, copper coated steel fibers varying from 0.5% to 1.5%. Samples with 1.5% fiber volume fraction were selected to be tested at high temperatures, up to 600ºC, to understand their durability and fire resistance. The results indicate a reduction in flexural strength of approximately 50% at 600ºC for all samples with and without fibers. The final objective of this research is to conduct an analysis of the ACI design code equations and other codes’ equations to better estimate the moment capacity of rectangular UHPC beams and prestressed UHPC box beams. This analysis creates an extensive database of 93 reinforced rectangular UHPC beams of various sizes, which are tested in flexure, to determine the accuracy of four different code equations. The code equations analyzed include the ACI 318-14 approach using the Whitney stress block analysis, the ACI 544-4R code for fiber reinforced concrete, the new equations proposed by the FHWA (2013), and the international code SIA 2052 equation derived by the Swiss Society of Engineers and Architects. The results reveal that both ACI codes are more conservative in predicting moment capacity than the Swiss and FHWA codes due to the enhanced compressive strength and the tensile strength from the fiber contribution. Using this information, and the principles of structural mechanics including strain compatibility, the moment capacities of partially prestressed UHPC box girders were determined. Utilizing UHPC in precast box beams increases their moment capacity which allows for smaller sections, longer span lengths, and accelerated bridge construction. Moment capacity equations are derived for partially prestressed UHPC box beams and design charts are developed for the smallest (BI-36) and largest (BIV-48) fully prestressed AASHTO box beams made with UHPC.
Alissa Celine Persad (Thu,) studied this question.