Abstract: The growing use of ionizing radiation across various fields has increased the demand for effective shielding materials. Representing a promising solution for radiation protection, Radiation Shielding Ultra-High-Performance Concrete (RS-UHPC) offers superior mechanical performance, durability, and radiation attenuation capabilities. While extensive research has been conducted on RS-UHPC gamma shielding properties, its attenuation of thermal neutrons remains largely unexplored. This study investigates the thermal neutron attenuation capabilities of RS-UHPC incorporating silica sand, magnetite, and ferroboron aggregates, while also evaluating their effects on density and compressive strength. The influence of aggregate type on RS-UHPC performance was quantified through a series of experimental tests on four mixtures: a control mixture (S) with silica sand, a magnetite-based mixture (M), and two ferroboron-containing mixtures (75S-25FeB and 42S-42M-16FeB). Results indicate that w...Read more

Abstract: With structural concrete constituting the ultimate physical barrier in nuclear facilities, the safety of the latter is contingent on the quality of concrete used therein. A highly promising contender for propelling nuclear safety is ultra-high-performance concrete (UHPC). Given its intrinsically dense microstructure, exceptional mechanical properties, and superior durability, UHPC has the potential to provide better confinement of radioactive substances and higher radiation shielding, thereby enhancing the Defense in Depth strategy of nuclear facilities. Currently, published knowledge on radiation shielding UHPC (RS-UHPC) is both scarce and fragmented. This review is focused on how RS-UHPC ingredients, particularly heavyweight materials, affect mixture rheology, microstructure, mechanical performance, radiation shielding efficiency, and durability of the end product. The study also provides insights into how the various heavyweight materials affect the residual mechanical and...Read more

Abstract: The nuclear sector, as a pivotal provider of clean energy, plays a crucial role in advancing green economies. This sector is currently experiencing a resurgence, particularly with the recent emphasis on small modular reactors (SMRs), signaling a significant momentum toward nuclear energy expansion. However, ensuring the safety of nuclear facilities remains critical for the responsible deployment of this technology. Radiation Shielding Ultra-High-Performance Concrete (RS-UHPC)—an advanced type of concrete engineered for optimal packing density to enhance mechanical properties and durability while effectively attenuating radiation—emerges as a promising solution for reinforcing the Defense in Depth (DiD) strategy in nuclear infrastructure. Nevertheless, the existing understanding of RS-UHPC is limited and dispersed. By the time of writing this review, the authors are unaware of any comprehensive review on the subject. This study aims to fill this gap by providing a thorough rev...Read more

Abstract: Engineered Cementitious Composites (ECC) are a special type of ultra-ductile fiber-reinforced concrete that uses microfibers. The bond strength of Polyethylene ECC with steel reinforcement was found to be not well investigated in the literature under both monotonic loading and cyclic loading conditions. This study aims to investigate the bond strength properties of Polyethylene ECC with steel reinforcement under monotonic and cyclic loading conditions and to evaluate the effect of embedment length, loading rate, and the cover on bond strength experimentally. The beam-end test was selected for this experiment since it is a relatively simple test, yet it produces a realistic stress field. The results indicated that ECC's main failure mode is splitting-pullout, with high slippages occurring. Furthermore, increasing the cover thickness from 3db to 4db enhanced the bond strength by 91%, while raising the anchorage length from 5db to 7db improved it by 105%. Increasing the load rat...Read more

Abstract: Concrete possesses good resistance to compressive stresses; however, it remains weak in resisting tensile stresses, making the formation of cracks in concrete members inevitable. The concrete’s durability is directly affected by the development of cracks, which are a direct pathway for deterioration agents that damage the concrete elements. Consequently, the reinforced concrete can experience corrosion, spalling, loss of strength, or progressive disintegration. One way to avoid such problems is to incorporate discrete fibers into the concrete matrix. The fibers act by bridging the gaps formed by cracks, thus, slowing down the crack-opening and propagation process. Studying the crack formation and propagation in the presence of material and geometric uncertainties is impossible using deterministic approaches. In the present paper, the crack propagation in fiber reinforced concrete (FRC) beams is studied from a probabilistic perspective considering the formation and propagation...Read more

Abstract: The bond between reinforcing steel and concrete is critical for the optimal performance of reinforced concrete (RC) structures. The same applies to structures incorporating short, randomly-distributed fibers in the cementitious matrix, such as Fiber Reinforced Concrete (FRC) and Engineering Cementitious Composites (ECC). Several studies have investigated the bond strength between steel and ECC because of the high ductility, energy absorption capacity, and damage tolerance of the latter. The present article reviewed several studies that investigated the steel/ECC bond strength. The studies showed that the steel/ECC bond outperformed conventional RC under both monotonic and cyclic loading conditions. The review revealed that more research was conducted using ECC mixes containing 2% Polyvinyl Alcohol (PVA) fibers than other types of fibers. Data from numerous papers discussing the steel/ECC bond with ECC mixes containing 2% PVA fibers were collected, and a bond strength predicti...Read more

Abstract: Driver distraction has become a major concern for road safety as distracted driving is a leading cause of car accidents, resulting in a large number of injuries and fatalities every year. This project aims to address the issue of driver distraction as a leading cause of traffic accidents worldwide. Utilizing various image datasets, the project explores the use of Convolutional Neural Networks (CNNs), specifically the DarkNet53 model, to classify whether drivers are focused on the road or distracted. A collection of publicly available datasets and a new dataset consisting of 4024 images produced by the authors were used in training the model, with image augmentation being used to significantly enhance the model performance. The training and testing processes were conducted using MATLAB and different techniques such as transfer learning and layer freezing were utilized to improve the training process. The real-time performance of the DarkNet53 model was also evaluated against o...Read more

Abstract: The surface of concrete pavement is susceptible to cracking. The propagation of a crack in a concrete structure may take the form of a one-dimensional line crack, a two-dimensional surface crack, or a three-dimensional volume crack. Predicting crack propagation in a concrete pavement surface is a complicated task. The whole process of formation, propagation, and orientation of cracks can be considered a stochastic process that necessitates a probabilistic investigation approach. In the present study, crack propagation in concrete pavements is studied from a probabilistic point of view using the concepts of multinomial Markov Chains using Random Walks. The study is based on actual probabilities of propagation and orientation of cracks obtained by tracing crack paths from a large dataset of images using custom-built software. Two random walker models are developed using the trinomial and multinomial Markov Chains. The master equation is developed assuming the trinomial Markov C...Read more