Other Materials Science and Engineering Commons^™

The Effect Of Calcium Nitrate On The Hydration Of Calcium Aluminate Cement At Different Curing Temperatures, Hongxia Wang, Guizhi Diao, Guanghua Liu, H Wang, Lixiong Gao, Guangwei Liu

International Conference on Durability of Concrete Structures

Phase conversion in calcium aluminate cements (CAC) induces significant volumetric instability; it would result in an increase in porosity and decrease in strength in CAC. In this study, calcium nitrate (CN) as a phase conversion inhibitor, the effect of CN on the hydration of CAC at different curing temperatures was studied. Xray diffraction, thermal analysis, SEM, isothermal calorimetry and the compressive strength were conducted on the CAC dosages of 0%, 5%, 10% and 15%CN cured at 20�, 30�, 40� and 50�. The results show CN can retard CAC hydration, alter the characters of the hydrates of CAC systems and avoid …

An Investigation Of High-Speed Consolidation And Repair Of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding, David A. Hoskins

LSU Master's Theses

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming.

In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using …

Optothermal Microbubble Assisted Manufacturing Of Nanogap-Rich Structures For Active Chemical Sensing, Farzia Karim, Erick S. Vasquez, Yvonne Sun, Chenglong Zhao

Chemical and Materials Engineering Faculty Publications

Guiding analytes to the sensing area is an indispensable step in a sensing system. Most of the sensing systems apply a passive sensing method, which waits for the analytes to diffuse towards the sensor. However, passive sensing methods limit the detection of analytes to a picomolar range on micro/nanosensors for a practical time scale. Therefore, active sensing methods need to be used to improve the detection limit in which the analytes are forced to concentrate on the sensors. In this article, we have demonstrated the manufacturing of nanogap-rich structures for active chemical sensing. Nanogap-rich structures are manufactured from metallic nanoparticles …

Biopolymer-Stabilized Earth Materials For Resilient And Adaptable Infrastructures, Sherif Abdelaziz, Dilip Gersappe, Dilip Rafailovich

Department of Civil Engineering Faculty Publications

Earth dams and levees are constructed and retrofitted nowadays using the same materials that were used in the past, clays and sands. Despite the current advances in engineering, designing and constructing these critical infrastructure, earthen dams and levees continue to suffer from the same challenges over the years. These challenges include internal and surface erosions, loss of stability due to moisture migration, and inabilities to self-heal potential failure points. This project focuses on the use of biopolymers as additives to strengthen earthen dams and levees targeting an overall increase in their resilience.

Explicitly, the report for Milestone 3 presented the …

Optimization And Structural Stability Of Gold Nanoparticle–Antibody Bioconjugates, Robert T. Busch, Farzia Karim, John Weis, Yvonne Sun, Chenglong Zhao

Chemical and Materials Engineering Faculty Publications

Gold nanoparticles (AuNPs) bound with biomolecules have emerged as suitable biosensors exploiting unique surface chemistries and optical properties. Many efforts have focused on antibody bioconjugation to AuNPs resulting in a sensitive bioconjugate to detect specific types of bacteria. Unfortunately, bacteria thrive under various harsh environments, and an understanding of bioconjugate stability is needed. Here, we show a method for optimizing Listeria monocytogenes polyclonal antibodies bioconjugation mechanisms to AuNPs via covalent binding at different pH values, from 2 to 11, and 2-(N-morpholino)ethanesulfonic acid (MES), 3-(N-morpholino)propanesulfonic acid, NaOH, HCl conditions. By fitting Lorentz curves to the amide I and II regions, we …

Mitigating Reflective Cracking Through The Use Of A Ductile Concrete Interlayer, Qian Zhang, Mohammad Khattak, Adway Das

Publications

Reflective cracking is considered one of the most important issues that causes premature deterioration of composite pavements. Many types of mitigation methods have been studied in the past. However, they are either not effective in delaying the reflective cracking, or they only extend the service life by a few years. To address this critical issue and significantly extend the service life of the composite pavement, in this research, a ductile interlayer made of engineered cementitious composites (ECC) was proposed. It was hypothesized that by adding a thin layer of highly ductile ECC material between the existing pavement and overlay, reflective …

Abrasion Resistance Of High Early-Strength Concrete For Rapid Repair, Nader Ghafoori, Matthew O. Maler, Meysam Najimi, Ariful Hasnat

Civil and Environmental Engineering and Construction Faculty Research

This paper examines the abrasion resistance of high early-strength concrete developed for rapid repair of highways and bridge decks. The cement types chosen for this study included ASTM Type III, ASTM Type V, and Calcium Sulfoaluminate (CSA) cements. A cement content of 386 kg/m3 (650 lb/yd3 ) was maintained for all studied concretes. Test samples were tested after 24 hours and 28 days of curing in order to evaluate compressive strength and depth of wear. Test results revealed that the opening time to attain minimum required compressive strength for CSA cement concrete was one hour, whereas the values for Type …

Computational And Experimental Approach To Understanding The Structural Interplay Of Self-Assembled End-Terminated Alkanethiolates On Gold Surfaces, Juganta K. Roy, Erick S. Vasquez, Henry P. Pinto, Swati Kumari, Keisha B. Walters, Jerzy Leszcynski

Chemical and Materials Engineering Faculty Publications

Applications of self-assembled monolayers (SAMs) on surfaces are prevalent in modern technologies and drives the need for a better understanding of the surface domain architecture of SAMs. To explore structural interaction at the interface between gold surfaces and a hydroxyl-terminated alkanethiol, 11-hydroxy-1-undecanethiol, (C11TH) we have employed a combined computational and experimental approach. Density functional theory (DFT) calculations were carried out on the thiol–gold interface using both the Perdew–Burke–Ernzerhof (PBE) and van der Waals (optB86b) density functionals. Our ab initio molecular dynamics (AIMD) simulations revealed that the interface consists of four different distinguished phases, each with different C11TH orientations. Experiments involved …

Optimizing The Valorization Of Industrial By-Products For The Induction Healing Of Asphalt Mixtures, Amir Tabakovic, Marta Vila-Cortavitarte, Daniel Jato-Espino, Daniel Castro-Fresno

Articles

Self-healing within asphalt pavements is the process whereby road cracks can be repaired automatically when thermal and mechanical conditions are met. To accelerate and improve this healing process, metal particles are added to asphalt mixtures. However, thisapproach is costly both in economic and environmental terms due to the use of virgin metallic particles. So, even though the self-healing of asphalt mixtures has been widely addressed in experimental terms over the years, there is a lack of research aimed at modelling this phenomenon, especially with the purpose of optimizing the use of metal particles through the valorization of industrial by-products. As …

Hydcem: A New Cement Hydration Model, Niall Holmes, Denis Kelliher, Mark Tyrer

Conference papers

Hydration models are useful to predict, understand and describe the behaviour of different cementitious-based systems. They are indispensable for undertaking long-term performance and service life predictions for existing and new products for generating quantitative data in the move towards more sustainable cements while optimising natural resources. One such application is the development of cement-based thermoelectric applications.

HYDCEM is a new model to predict the phase assemblage, degree of hydration, heat release and changes in pore solution chemistry over time for cements undergoing hydration for any w/c ratio and curing temperatures up to 450C. HYDCEM, written in MATLAB, is aimed at …

Development Of Experimental And Finite Element Models To Show Size Effects In The Forming Of Thin Sheet Metals, Jeffrey D. Morris

LSU New Orleans Theses and Dissertations

Abstract

An experimental method was developed that demonstrated the size effects in forming thin sheet metals, and a finite element model was developed to predict the effects demonstrated by the experiment. A universal testing machine (UTM) was used to form aluminum and copper of varying thicknesses (less than 1mm) into a hemispherical dome. A stereolithography additive manufacturing technology was used to fabricate the punch and die from a UV curing resin. There was agreement between the experimental and numerical models. The results showed that geometric size effects were significant for both materials, and these effects increased as the thickness of …

Elimination Of Empirical, Ineffective And Expensive Pg Plus Tests To Characterize Modified Binders, Zahid Hossain, Ashraf Elsayed, Mm Tariq Morshed, Mohammad Hassan

Data

Corresponding data set for Tran-SET Project No. 18BASU02. Abstract of the final report is stated below for reference:

"For characterizing the polymer modified binders, different state Departments of Transportation (DOTs) use different time consuming and empirical Performance Grade (PG) Plus test methods. Furthermore, the PG Plus tests are silent when asphalt binders are modified with chemicals such as polyphosphoric acid (PPA). But, the effects of the elastomeric or plastomeric polymer are not accurately identified through these conventional tests such as Elastic Recovery (ER) and tenacity. Thus, the main research goal of this study is to recommend alternative test method(s), which …

Development Of A Methodology For Characterizing Reaction Kinetics, Rheology, And In-Situ Compaction Of Polyimide Prepregs During Cure, James Raymond Magato, Donald A. Klosterman

Chemical and Materials Engineering Faculty Publications

PMR-type polyimide prepregs are challenging to fabricate into high quality composites due to volatiles that are generated and must be removed in situ during processing. The current work was conducted to develop accurate, reliable, and practical characterization techniques of the prepreg rheology, volatile generation, and subsequent volatile removal from the prepreg during composite fabrication. Thermal analysis was used to characterize volatile generation, reaction rates, and rheology. A novel approach was used to measure the thickness of the prepreg in situ during vacuum bag/oven processing using a high-temperature LVDT. Experimental results are presented for the commercially available RM-1100 polyimide/carbon prepreg system, …

Elimination Of Empirical, Ineffective And Expensive Pg Plus Tests To Characterize Modified Binders, Zahid Hossain, Ashraf Elsayed, Mm Tariq Morshed, Mohammad Hassan

Publications

For characterizing the polymer modified binders, different state Departments of Transportation (DOTs) use different time consuming and empirical Performance Grade (PG) Plus test methods. Furthermore, the PG Plus tests are silent when asphalt binders are modified with chemicals such as polyphosphoric acid (PPA). But, the effects of the elastomeric or plastomeric polymer are not accurately identified through these conventional tests such as Elastic Recovery (ER) and tenacity. Thus, the main research goal of this study is to recommend alternative test method(s), which can possibly be pursued by using a commonly available device, a Dynamic Shear Rheometer (DSR). Three PG binders …

Use Of Rice Husk Ash (Rha) In Flowable Fill Concrete Mix Material, Zahid Hossain, Kazi Tamzidul Islam

Publications

In the way of finding sustainable development, the flowable fill is a relatively new construction technology. Flowable fill is a self-compacting material, which has been developed in recent years. Flowable fill has been used for different applications such as backfilling walls, sewer trenches, bridge abutments, conduit trenches, pile excavations, and retaining walls. This study examines the potential uses of Rice Husk Ash (RHA) as a sustainable cementitious material (SCM) in the preparation of flowable fill concrete. (RHA is an agricultural by-product of the rice milling process. This study has evaluated the usage of RHA in producing low strength and self-consolidating …

Self-Healing Concrete Using Encapsulated Bacterial Spores In A Simulated Hot Subtropical Climate, Marwa Hassan, Jose Milla, Tyson Rupnow, Ahsennur Soysal

Publications

Bacterial concrete has become one of the most promising self-healing alternatives due to its capability to seal crack widths through microbial induced calcite precipitation (MICP). In this study, two bacterial strains were embedded at varying dosages (by weight of cement) in concrete. Beam specimens were used to identify the maximum crack-sealing efficiency, while cylinder samples were used to determine their effects on the intrinsic mechanical properties, as well as its stiffness recovery over time after inducing damage. The concrete specimens were cured in wet-dry cycles to determine their feasibility in Region 6. The results showed that the specimen groups with …

Use Of Bagasse Ash As A Concrete Additive For Road Pavement Application, Gabriel Arce, Marwa Hassan, Maria Gutierrez, Michele Barbato

Publications

The objective of this study was to evaluate the use of sugarcane bagasse ash (SCBA) as a partial replacement of cement in concrete for road pavement application. The study explored the pozzolanic activity of SCBA produced from three different processing methodologies (i.e., raw SCBA, controlled SCBA and post-processed SCBA). The experimental results revealed that SCBA produced by the controlled burning of sugarcane bagasse fiber (SBF) at 650°C and grinding (C-650), presented the maximum pozzolanic activity. However, this SCBA production process was deemed challenging for large-scale industrial application due to low SCBA yield (i.e., 3 to 6%). On the other hand, …

Manipulating Fiber Orientation For The Reduction Of Warpage In Carbon Fiber Composite Sandwich Panels, Landon Burnley, Gabrielle Correia

Materials Engineering

Safran Cabin (Santa Maria, CA), previously known as Zodiac Aerospace, designs and manufactures interior cabin components for private and commercial aircraft. Carbon fiber face sheets have recently been incorporated in their overhead luggage bin assemblies which utilize a composite sandwich panel design, in order to provide additional stiffness to the previous glass fiber sandwich panels. Since the introduction of carbon fiber in these luggage bin panels, Safran has experienced an increase in warpage during manufacturing. When inspected by quality control, the panels are tested mimicking how they are installed in aircraft. If the panels do not meet specifications, the warped …

Experimental And Theoretical Evaluation Of The Effect Of Panel Geometry On The Failure Of Corrugated Board Panel, Takashi Takayama, Katsuhiko Saito, Akira Higashiyama

Journal of Applied Packaging Research

McKee’s formula is widely used to predict the compression strength (CS) of corrugated boxes and panels. It can accurately estimate the compression strength of boxes that are within a practical size range, but recently, larger and smaller corrugated boxes than before have been extensively developed. Therefore, there is a need for a CS prediction formula that works beyond the application range of McKee’s formula. Recent researches consider the failure mode as a combination of collapsing and buckling failure and remove the constraints and the assumptions associated with McKee’s formula. This makes it possible to more accurately estimate the CS of …

Erosion Resistance Of Tungsten-Carbide Coatings For Steel Pipes In Fluid Catalytic Cracking Units, Davis Vannasing, Jennifer Hulfachor

Materials Engineering

In petroleum processing, the flow of catalyst readily leads to erosion of piping in a fluid catalytic cracking unit. Advances in coating materials and processes necessitate a re-evaluation of current protection methods. Commercially available tungsten-carbide (WC) claddings and nanostructured WC-W CVD coatings were investigated as potential alternative erosion-resistant coatings. Erosion tests by solid particle impingement were conducted on 2 variations of claddings and 1 variation of WC-W coatings following ASTM standard G76. A36 steel coupons were used as reference samples. For statistical validation, 2-3 replications of the tests were performed for the claddings and WC-W coating. Testing was conducted using …