Engineering Commons^™

Austenitic, Duplex, And Lean Duplex Stainless Steel Critical Pitting Temperature In Simulated Concrete Environment, Bobby Giebel

Williams Honors College, Honors Research Projects

In this work, the critical pitting temperature (CPT) will be observed for a selection of austenitic (316LN and 24100) and duplex (2205), and lean duplex (2304, 2001) stainless steels in simulated concrete pore solution. To study the influence of temperature on the pitting stability of the stainless steels, three temperatures were tested: 25oC, 45oC, and 65oC for cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). Electrochemical properties of the interfaces we studied via EIS analysis. Kinetics were studied via CPP testing. To reveal the critical pitting temperature of the stainless steels, cyclic thermammetry was used. Characterization of the pits …

Uncertainty Of The Ultrasonic Method For Determining The Strength Of Concrete, Ortagoli Sharipovich Hakimov, Zamira Khudoyberdiyevna Ernazarova

Chemical Technology, Control and Management

The issues of measuring the strength of concrete by the method of surface sounding by ultrasound are considered. A measurement model and formulas for estimating the total standard measurement uncertainty, information about the standards used, measurement tools and methods, and environmental parameters are given. Information about the estimation of uncertainty in the form of "eight steps", such as: measurement task; mathematical model of measurement; analysis of input values; observation results; correlations; uncertainty budget; expanded uncertainty; measurement result. It has been established that the uncertainty of type B of the ultrasonic method for determining the strength of concrete is much less …

Features Of Hydration Process, Structure Formation And Curing Processes Of Mono And Polymineral Cement In The Presence Of Additives Of Solid Waste Of Soda Production, Nargis Shamadinova, Gulnora Abdukadirovna Tokhtakhunova Phd, Temur Azimovich Atakuziev, Shakhnoza Saidanvarovna Rakhimjanova

Chemical Technology, Control and Management

The influence of the additive of solid waste of soda production (SWSP) on the content of -C₂S and C₃S in cement studied. It was found that SWSP affects the density of the aluminum-containing minerals C₃A and C₄AF, in addition, in the presence of gypsum, their plasticizing properties improved. The introduction of SWSP additives during grinding of clinker intensifies the grinding process and made it possible to obtain a more plastic cement. It was proved that SWSP with CaCl₂ content can be used as an additive to concrete and cement mortars - …

The Production Of Pyrolytic Biochar For Addition In Value-Added Composite Material, Douglas Matthew Cuthbertson

Electronic Thesis and Dissertation Repository

Pyrolytic biochar has recently gained attention for its potential value as a carbon sequestering by-product that can be used in industrial applications. While biochar is typically targeted for soil amendment applications, higher value applications such as addition in consumer products and building materials needs to be investigated.

In this study, biochar is produced from three different Canadian feedstocks using three different pyrolysis methods. The biochar is characterized to determine the effects that feedstock selection and pyrolysis conditions has on biochar properties. The biochar is also incorporated into concrete at varying concentrations to create a lightweight and sustainable material. The effect …

Evaluating The Bond Behavior Between Frp And Grooved Concrete Specimens Using Single Shear Pull Out Test, John Omboko

Master's Theses (2009 -)

Surface preparation affects the bond behavior between Fiber Reinforcing Polymer (FRP) composite material and concrete. In this research, a special type of surface preparation known as grooving, which involves cutting transverse grooves, is conducted on concrete blocks (specimens) that are categorized as either Unfilled (U) or Filled (F). This idea is to ascertain how the grooves affect the strength of FRP-bonded-concrete specimen. These two categories are then benchmarked to control (C) specimens which do not have grooves on them. Category U specimens only have the epoxy applied on the concrete surface while category F specimens have epoxy applied on both …

Chemical Modification Of Crumb Rubber To Increase Its Bonding With Concrete, Mary T. Mccannon, Kendall J. Sweitzer

Williams Honors College, Honors Research Projects

The hydrophilicity of crumb rubber was increased with wet chemical modification and added to concrete to increase its adhesion with concrete, consequently the compressive strength relative to that of concrete with untreated rubber. Other modification methods were tested on crumb rubber and rubber sheets to yield an increase in hydrophilicity. Certain tests were less reliable for powder testing or tedious and time consuming and concrete materials and rubber may not be homogeneous.

For wet chemical modification, several approaches were attempted. First, crumb rubber was soaked in 5% sodium hydroxide, 5% potassium permanganate and saturated sodium bisulfite, tested for hydrophilicity using …

Effect Of Fly Ash Fortification In The Manufacture Process Of Making Concrete Towards Characteristics Of Concrete In Sulfuric Acid Solution, Asep Handaya Saputra, Muhammad Shohibi, Masatoshi Kubouchi

Makara Journal of Technology

Fly ash is a silica or alumino silica material that can be used as a constituent of cement in the concrete manufacturing process. Utilization of fly ash aims to improve durability and minimize the reduction of concrete’s compressive strength exposed to an acidic environment, which can be achieved through the pozzolanic reaction of fly ash with Ca(OH)2 within concrete. The reduced content of Ca(OH)2 through pozzolanic reaction will minimize the tendency of ettringite formation (compounds that cause deterioration and decrease the compressive strength of concrete). In order to determine the relation between fly ash replenishment into concrete with concrete’s characteristics …

Feasibility Of Cathodic Protection In Grouted Post Tensioned Tendons - Exploratory Model Calculations, Jacob Dharma Bumgardner

USF Tampa Graduate Theses and Dissertations

Recent corrosion related failures of grouted post tensioned tendons, even after the introduction of improved grouts, have led to renewed interest in supplemental or backup means of corrosion control for these systems. A finite element model is presented to explore feasibility of impressed current cathodic protection of strand in grouted tendons. The model examines polarization evolution as function of service time and includes consideration of anode placement and size, grout porosity, pore water alkalinity, electrochemical species diffusivity and applied voltage on the polarization efficacy and durability of such a system. The exploratory model projections suggested that, within the context of …

Kelvin Probe Electrode For Contactless Potential Measurement On Concrete-Properties And Applications, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

The practical feasibility of using a Kelvin Probe as a novel reference electrode in the measurement of both potential and polarization pulse response of reinforcing steel in concrete is demonstrated. Potential values measured using a KP reflect greater stability and repeatability than can typically be attained with conventional reference electrodes. Duplicate reinforced concrete beam test specimens with well-differentiated centrally corroding rebar segments were analyzed using both the Kelvin Probe (KP) and a conventional Saturated Calomel Electrode (SCE). Potential profile maps were developed using potential values recorded under static conditions with both the SCE and the KP. Nominal polarization resistance was …

Biomass And Coal Fly Ash In Concrete: Strength, Durability, Microstructure, Quantitative Kinetics Of Pozzolanic Reaction And Alkali Silica Reaction Investigations., Shuangzhen Wang

Theses and Dissertations

Biomass represents an important sustainable energy resource, with biomass-coal cofiring representing among the most effective and cost efficient CO2 reduction strategies. Fly ash generated during coal combustion represents a technically advantageous, inexpensive, and environmentally beneficial admixture in concrete production, partially replacing cement. However, strict interpretation of American Society of Testing and Materials (ASTM) and American Concrete Institute (ACI) standards prohibits use of fly ashes from any source other than coal in concrete production; therefore, fly ash from biomass coal cofiring is excluded from use in concrete. This dissertation discusses biomass impacts on concrete properties through experiments conducted on several combinations …

Synthesis And Application Of Polymeric Corrosion Inhibitor For Reinforced Concrete, Weiwei Lin, Shengxian Wang, Jianqing Zhang

Journal of Electrochemistry

A new polymer E Twas synthesized and used as a corrosion inhibitor for reinforced concrete. The inhibitive behavior and mechanism were studied with linear polarization ,Tafel polarization,EIS and XPS method in simulated pore solution system with concrete samples.The result showed that the polymer was a mixing type inhibitor. A 1% dosage was sufficient to imhibit the corrosion of steel in simulated pore solution system. The salt endurance was enhanced from 0.02 mol/L to 0.10 mol/L.The result also showed the good synergetic effect of NaNO 2,especially in low NaNO 2 concentration.The EIS showed that E_T has dual function on reinforced concrete,i.e.,densifying …