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Full-Text Articles in Engineering
Optimization Of The Self-Healing Efficiency Of Bacterial Concrete Using Impregnation Of Three Different Precursors Into Lightweight Aggregate, Omar Omar
LSU Master's Theses
Concrete is the most broadly used construction material; thus, developing sustainable concrete is essential to decrease greenhouse gas (GHG) emissions from concrete production. Implementation of self-healing concrete technologies is a promising approach to enhance the durability and sustainability of the transportation infrastructure. Among these technologies, bacterial concrete has the potential to seal microcracks through microbial induced calcite precipitation (MICP). Bacterial protection is essential to ensure the viability of this technology due to concrete’s harsh environment. Additionally, the success of this technology depends on the presence of an adequate mineral precursor compound and nutrient for the bacteria. As such, the main …
Shape Memory Polymer-Based Multifunctional Syntactic Foams, Siavash Sarrafan
Shape Memory Polymer-Based Multifunctional Syntactic Foams, Siavash Sarrafan
LSU Doctoral Dissertations
With the increase in popularity of shape memory polymers (SMPs), especially in applications such as aerospace, textile, biomedical engineering, and even structures, the weight of the material and the devices made with it has always been a crucial factor. Using the shape memory polymer as a matrix to make a syntactic foam is one of the best and most affordable approaches to creating a lighter material that still has the shape memory effect. The addition of particles of different stiffness, strength, and size, with variable fractions, creates a composite that enables engineering the mechanical, as well as other physical and …
Effect Of Light Activated Self-Healing Polymers On The Performance Of Asphalt Pavement Containing Recycled Asphalt Materials (Rap/Ras), Sharareh Shirzad
Effect Of Light Activated Self-Healing Polymers On The Performance Of Asphalt Pavement Containing Recycled Asphalt Materials (Rap/Ras), Sharareh Shirzad
LSU Doctoral Dissertations
A new generation of Ultraviolet (UV) light-induced self-healing polymers was introduced for the asphalt pavement application with the aim to enhance pavements durability while increasing its service life. The developed self-healing polymer was mixed with asphalt binder using two different methods, passive and reactive. For the passive method, the cured self-healing polymer was ground to smaller particle size and then it was mixed with asphalt binder using a high shear stirrer and at a high temperature. For the reactive method, self-healing polyurethane pre-polymer was added to the asphalt binder at a lower temperature and lower shear rate compare to the …
Healing Mechanism Investigation Of Self-Healing Concrete By Microencapsulated Calcium Nitrate, Gabriel Andres Arce Amador
Healing Mechanism Investigation Of Self-Healing Concrete By Microencapsulated Calcium Nitrate, Gabriel Andres Arce Amador
LSU Doctoral Dissertations
Durability of reinforced concrete structures depends highly on the integrity of the concrete which protects the structure from the environment. However, concrete is a brittle material and as such it is prone to cracking which allows for detrimental agents to penetrate the structure and produce early deterioration. Embedding microcapsules with chemical healing agents in concrete materials for self-healing applications as well as implementing SMAs as reinforcement of concrete structures for self-closing of cracks are both state-of-the-art techniques with enormous potential for enhancement of concrete infrastructure durability. In this work, both techniques are combined as an alternative for superior self-healing of …
Integration Of Shape-Memory Alloys And Self-Healing Microcapsules To Enhance Concrete Durability, Luis Adolfo Bonilla
Integration Of Shape-Memory Alloys And Self-Healing Microcapsules To Enhance Concrete Durability, Luis Adolfo Bonilla
LSU Doctoral Dissertations
Self-healing is a term that has not been used for building material until a few decades ago. The concept of developing a material that mimics what living organisms do, such as identify and repair damage, rather than interesting, constitutes a necessity in today’s deteriorated infrastructure. Concrete is one of the main building blocks that support our society’s roads, buildings, and dams. Increasing the service life of such structures will have an important socio-economic benefit in our society. Self-healing methods in concrete have been studied in order to minimize human intervention in maintenance procedures. Previous research in this area has provided …
Healing-On-Demand Polymer Composites Based On Shape Memory Polyurethane Fibers And Polymeric Artificial Muscles, Pengfei Zhang
Healing-On-Demand Polymer Composites Based On Shape Memory Polyurethane Fibers And Polymeric Artificial Muscles, Pengfei Zhang
LSU Doctoral Dissertations
In this dissertation, the healing-on-demand polymer composites based on shape memory polyurethane fibers and artificial muscles are investigated, for understanding and developing a novel healing-on-demand composite so that it would be used for industrial applications that could heal structural-length scale damage and leaking autonomously, repeatedly, efficiently, timely, and molecularly. Firstly, the structural relaxation behavior of shape memory polyurethane (SMPU) fiber was studied by theoretical analysis and experimental test. Then, a self-healing composite based on cold-drawn short SMPU fiber was prepared and tested for evaluating its crack-healing performance. After that, polymer artificial muscle based healing-on-demand composite was developed and characterized. Based …
Crack Self-Healing In Sic/Spinel Nanocomposite, Fariborz Tavangarian
Crack Self-Healing In Sic/Spinel Nanocomposite, Fariborz Tavangarian
LSU Doctoral Dissertations
Spinel is one of the best known and widely used ceramic materials. It has good thermal shock resistance, high chemical inertness in both acidic and basic environments, excellent optical and dielectric properties, high strength at both elevated and normal temperatures, and has no phase transition up to the melting temperature (2135°C). Spinel is used in the metallurgical, electrochemical, and chemical industrial fields. It has also found some applications in dentistry, catalyst supports, humidity sensors, reinforcing fibers, photoluminescent materials, etc. One of the limitations of spinel ceramic is its brittleness. Furthermore, at high temperature applications, a rapid heating or cooling can …
Effects Of Partial Confinement And Local Heating On Healing Efficiencies Of Self-Healing Particulate Composites, Jonah Champagne
Effects Of Partial Confinement And Local Heating On Healing Efficiencies Of Self-Healing Particulate Composites, Jonah Champagne
LSU Master's Theses
Shape memory polymers are smart materials that can be trained to hold a temporary shape through programming and regain their original shape upon heating. Since there discovery in the 1960s, much research has been devoted to the study of these polymers. Of particular interest in recent years is the study of self-healing shape memory polymers. In a previous study, it has been shown that in order for efficient healing to take place in self-healing shape memory polymers, confinement during healing is essential. Moreover, a two-step close-then-heal (CTH) approach to healing was suggested. It was shown that use of this CTH …
Programming And Healing Temperature Effects On The Efficiency Of Confined Self-Healing Polymers, Yves Quentin Yougoubare
Programming And Healing Temperature Effects On The Efficiency Of Confined Self-Healing Polymers, Yves Quentin Yougoubare
LSU Master's Theses
Shape memory polymers are smart materials capable of fixing a temporary shape and returning to their initial shape in response to an external stimulus. Since the discovery and acknowledgment of their importance in 1960s, shape memory polymers have been the subject of tremendous and continuous attention. In a previous study conducted on a biomimetic shape memory polymer (SMP), the ability of a self-healing composite to heal, and to repair and restore structural-length scale damage using a close-then-heal (CTH) self-healing mechanism was examined and validated. The present study is purposed with investigation of the effects on healing efficiencies of the variation …
Thermomechanical Characterization Of A Shape Memory Polymer Based Syntactic Foam, Damon Nettles
Thermomechanical Characterization Of A Shape Memory Polymer Based Syntactic Foam, Damon Nettles
LSU Master's Theses
Shape memory polymers (SMPs) are a type of smart material capable of “remembering” multiple shapes and transitioning between them in response to an external stimulus. They offer the potential to self-seal macro-length scale damage in a nearly autonomous fashion. Syntactic foams are lightweight structural materials currently used in the marine and aerospace industries. This study seeks to bring syntactic foams and SMPs together, retaining characteristics of both components, to create a low-density smart composite. The SMP based syntactic foam is used as the core of a grid stiffened sandwich structure capable of healing impact damage multiple times. In order to …