A Comparative Analysis of Reinforced Concrete and Fiber-Reinforced Concrete Durability

Thesis Abstract

The durability of concrete structures remains a critical factor influencing their longevity, maintenance requirements, and overall safety in civil engineering practices. Reinforced concrete (RC) has been the conventional material for structural applications worldwide, yet escalating infrastructure failures due to durability issues necessitate a comparative assessment with fiber-reinforced concrete (FRC), which incorporates discrete fibers to enhance performance. This study aims to systematically compare the durability characteristics of RC and FRC, focusing on their resistance to environmental deterioration, cracking, and corrosion over time. The specific objectives include evaluating the effects of environmental exposure on compressive strength degradation, analyzing crack propagation patterns, assessing corrosion resistance, and identifying the key microstructural factors contributing to durability differences between RC and FRC. The research adopts a mixed-methods approach, integrating quantitative laboratory experiments with qualitative microstructural analyses. The study population comprises twenty concrete mixes—ten RC mixes and ten FRC mixes containing polypropylene, steel, and glass fibers—prepared according to ASTM standards. A stratified sampling technique ensures representation of various fiber types and dosages, with a sample size of 60 specimens (three specimens per mix per test). Data collection involves standardized durability tests, including accelerated sulfate attack, freeze-thaw resistance, chloride penetration, and corrosion potential assessments, performed over a 12-month period. Microstructural analysis employs scanning electron microscopy (SEM) and X-ray diffraction (XRD) to examine pore structure, fiber-matrix interfaces, and microcrack development. Data analysis utilizes analysis of variance (ANOVA) to compare durability metrics across concrete types, regression analysis to quantify relationships between microstructural features and durability outcomes, and thematic analysis of qualitative microstructure observations. Expected findings suggest that FRC exhibits significantly superior resistance to chloride ingress, crack propagation, and corrosion under aggressive environmental conditions compared to traditional RC, attributable to the discrete fibers hindering crack growth and microstructural densification. Microstructural examinations are anticipated to reveal improved pore size distribution and enhanced fiber-matrix bonding in FRC specimens, underpinning their enhanced durability performance. The study's results will contribute an empirically validated understanding of how fiber reinforcement modifies durability pathways, bridging knowledge gaps concerning the microstructural mechanisms involved. The findings are expected to advance existing theories on concrete durability by integrating the principles of the toughening mechanisms introduced by fiber inclusion with microstructural deterioration models. The research anticipates contributing to practical guidelines for selecting fiber types and dosages in durability-sensitive applications, potentially influencing standards and design codes. The study addresses practical engineering challenges by providing data-driven insights into the long-term performance of FRC relative to RC, fostering more durable and sustainable infrastructure development. In conclusion, this research underscores the enhanced durability potential of fiber-reinforced concrete in harsh environmental conditions, recommending its broader adoption where durability is paramount. The study advocates for further research into optimizing fiber content and exploring other fiber types to maximize durability benefits. These findings aim to inform researchers, practitioners, and policymakers, ultimately promoting innovative, durable, and cost-effective concrete structures capable of withstanding evolving infrastructural demands.