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Influence Of Coating Defects Within The Lock Seams On The Corrosion Performance Of Aluminized Steel Drainage Pipes, Mohammed Al Yaarubi
Influence Of Coating Defects Within The Lock Seams On The Corrosion Performance Of Aluminized Steel Drainage Pipes, Mohammed Al Yaarubi
USF Tampa Graduate Theses and Dissertations
The electrochemical behavior of aluminized steel is investigated to determine the corrosion performance of coating deficiencies generated within the lock seams during the fabrication of aluminized steel corrugated pipe. Electrochemical techniques and visual and profilometric analysis are used to assess the ability of the aluminum and zinc coating to provide sufficient galvanic protection to the underlying steel in the presence of a crevice. Also, Crevice coupons and lock-seam samples were used in this investigation in different environmental conditions simulating natural water conditions to relate the corrosion rate with the level of protection that the coating will provide. In addition, a …
Effects Of Physical And Chemical Characteristics Of Slags And Cements On Durability Of Portland Cement-Slag Blended Systems, Farzaneh Nosouhian
Effects Of Physical And Chemical Characteristics Of Slags And Cements On Durability Of Portland Cement-Slag Blended Systems, Farzaneh Nosouhian
USF Tampa Graduate Theses and Dissertations
Ground granulated blast furnace slag (GGBFS) which is a commonly used supplementary cementitious material (SCM) needs to be more investigated for improving durability of concrete elements and service life of concrete structures. This research focuses on the effect of the physical and chemical characteristics of GGBFS and portland cement on durability of portland cement-slag blended systems. The effect of cement replacement level is also investigated using control mixes (no slag) and four different levels of slag content. To this end, eight GGBFS and eight portland cements were selected based on their physical characteristics and chemical composition. Four series of experimental …
Influence Of Exposure Environments On The Durability Of Slag-Blended Cements, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black
Influence Of Exposure Environments On The Durability Of Slag-Blended Cements, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black
International Conference on Durability of Concrete Structures
Both chlorides and sulphates combine in seawater to affect the durability of reinforced concrete structures located in marine environments. This paper presents the results of an experimental study on slag blended cement systems, cured for 7 days, before exposure to a combined solution of sodium chloride (30 g/L) and sodium sulphate (3 g/L). Two slags of different chemical compositions, designated as slags 1 and 2 were respectively blended with Portland cement CEM I 52.5R at 30 and 70 wt.% replacement levels. Mechanical tests on mortar samples were complemented by microstructural examination and chemical characterisation on paste samples, all using a …
Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener
Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener
International Conference on Durability of Concrete Structures
This work presents the results of an investigation carried out to assess durability of concrete made with a calcined clay- limestone-Portland cement with 47% of clinker, hereafter named LC3, produced during an industrial trial in 2013. LC3 was used to cast concrete blocks and later expose them at a natural location at the northern coast of Cuba. Reference concrete was cast with Cuban Portland cement having 88% of clinker. Throughout three years (2015, 2016, 2017) concrete cores were systematically taken and the specimens were subjected to a testing program that included Formation factor, chloride profiling, surface resistivity, air permeability and …
Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black
Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black
International Conference on Durability of Concrete Structures
This experimental study investigates the effects of temperature and curing duration on the stability of slag blended cement systems exposed at 20 °C and 38 °C to combined sodium chloride (30 g/L) – sodium sulphate (3 g/L) solutions. Two slags, designated as slag 1 and 2, having CaO/SiO2 ratios of 1.05 and 0.94, were respectively blended with Portland cement CEM I 52.5R at 30 wt.% replacement level. Mortar prisms and cubes with w/b ratio of 0.5 and binder/aggregate ratio of 1:3 were then prepared for length and mass changes. The samples were cured in lime water for either 7 …
On The Role Of The Pore Water Chemistry Of Deficient Post-Tension Grout To Promote Steel Corrosion, Samanbar Permeh
On The Role Of The Pore Water Chemistry Of Deficient Post-Tension Grout To Promote Steel Corrosion, Samanbar Permeh
FIU Electronic Theses and Dissertations
Corrosion failure of post-tension tendons with pre-packaged thixotropic grout was documented in Florida Bridges in less than 10 years of service. Analysis of deficient grout in Florida post-tensioned (PT) bridges where severe corrosion developed indicated enhanced sulfate ion concentration, high pore water pH, enhanced moisture and low chloride content. The corrosion wasn’t consistent with the conventional causes of steel corrosion such as bleed water accumulation in grout void spaces, chloride contamination and pore water carbonation. Corrosion development was associated with deficient grout with enhanced sulfate levels. However, limited information is available on the corrosion behavior of PT strand in grout …
Corrosion Of Steel In Submerged Concrete Structures, Michael Thomas Walsh
Corrosion Of Steel In Submerged Concrete Structures, Michael Thomas Walsh
USF Tampa Graduate Theses and Dissertations
This investigation determined that severe corrosion of steel can occur in the submerged portions of reinforced concrete structures in marine environments. Field studies of decommissioned pilings from actual bridges revealed multiple instances of strong corrosion localization, showing appreciable local loss of steel cross-section. Quantitative understanding of the phenomenon and its causes was developed and articulated in the form of a predictive model. The predictive model output was consistent with both the corrosion rate estimates and the extent of corrosion localization observed in the field observations. The most likely explanation for the observed phenomena that emerged from the understanding and modeling …
Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han
Influence Of Fly Ash On Surface Chloride Concentration Under Shallow Immersion Condition, Jun Liu, Xiaodong Wang, Feng Xing, Ningxu Han
International Conference on Durability of Concrete Structures
In this paper, the influence of fly ash content on concrete surface chloride concentration was investigated through periodical tests of surface chloride concentration of concrete by immersing three kinds of concrete specimens in 5.0 wt.% sodium chloride solution. One kind of specimen is common concrete without fly ash, whereas the other two kinds of specimens are mixed with fly ash. The results show that the surface chloride ion concentration ranges from 0.295 to 0.777 wt.% for the immersed concrete samples in this study; in the initial stage of immersion, the concrete surface chloride ion concentration is affected by added fly …
Electrochemical-Mechanistic Model For Concrete Cover Cracking Due To Corrosion Initiated By Chloride Diffusion, Goli Nossoni, Ronald S. Harichandran
Electrochemical-Mechanistic Model For Concrete Cover Cracking Due To Corrosion Initiated By Chloride Diffusion, Goli Nossoni, Ronald S. Harichandran
Civil Engineering Faculty Publications
A holistic electrochemical-mechanistic model of the corrosion of steel reinforcing bars inside concrete that accounts for the diffusion of oxygen and moisture into the concrete and rust layers, the densification of rust due to confinement, the flow of rust into the concrete pores, the development of internal pressure due to rust buildup, and cracking of the concrete cover is presented. The relationship between the corrosion current and the pressure buildup due to the corrosion products for different concrete cover thicknesses and concrete quality was calibrated through experiments using an accelerated corrosion test with an applied current. Results from finite-element analysis …
Mitigation Of Chloride And Sulfate Based Corrosion In Reinforced Concrete Via Electrokinetic Nanoparticle Treatment, Kunal Kupwade-Patil
Mitigation Of Chloride And Sulfate Based Corrosion In Reinforced Concrete Via Electrokinetic Nanoparticle Treatment, Kunal Kupwade-Patil
Doctoral Dissertations
Concrete is a porous material which is susceptible to the migration of highly deleterious species such as chlorides and sulfates. Various external sources, including sea salt spray, direct seawater wetting, deicing salts and chlorides can contaminate reinforced concrete. Chlorides diffuse into the capillary pores of concrete and come into contact with the reinforcement. When chloride concentration at the reinforcement exceeds a threshold level it breaks down the passive oxide layer, leading to chloride induced corrosion. The application of electrokinetics using positively charged nanoparticles for corrosion protection in reinforced concrete structures is an emerging technology. This technique involves the principle of …