Download or read book Corrosion Effects of Cement Stabilized Backfill on Galvanized Steel Earth Reinforcements written by Derek V. Morris and published by . This book was released on 1994 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cement stabilization of backfill has been used for some time in mechanically stabilized earth type retaining walls. However, there has been no data on the corrosion life of galvanized steel reinforcement in this environment, which is intermediate in pH between normal soil and pure cement. Field observations had indicated a potential corrosion problem at a particular site in District 12. As a result of the test program conducted during this project, the following conclusions were made. First, cement addition to backfill in the usual quantities (i.e. 7% or more) raised the pH environment to values close to that of normal concrete. At these levels corrosion rates of zinc coatings were not significantly accelerated -- if anything, corrosion rates were less than for unstabilized fill. Second, very small amounts of cement addition, of the order of 1% to 4% producing pH values significantly less than 12, could cause limited acceleration of corrosion. It is, therefore, advisable to control minimum cement levels and to encourage efficient mixing. Third, elevated corrosion rates were associated primarily with the presence of inorganic ions, both for stabilized and unstabilized fill. In the case of the problem site in District 12, this appeared to be the result primarily of unusually high sulfate content in the fill. Fourth, the use of crushed concrete as backfill did not accelerate corrosion. This material, therefore, appears to be acceptable for this application.

Download or read book Corrosion Effect of Stray Currents and the Techniques for Evaluating Corrosion of Rebars in Concrete written by Victor Chaker and published by ASTM International. This book was released on 1986 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Long Term Corrosion of Reinforcing Strips in Mechanically Stabilized Earth Walls written by Brandon Seth Berke and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Mechanically stabilized earth (MSE) walls are a more advanced form of a retaining wall, often larger and able to hold back more backfill. This is achieved by reinforcing strips or meshes (most often galvanized steel) placed into the soil, which are held in place by friction. The strips mechanically stabilize the earth while undergoing tension. The wall is covered with concrete medallions that connect to the reinforcements. The medallions have only a secondary structural role in holding up the wall but provide cover that protects the soil from washing away. MSE walls are structures expected to have very long service lives (e.g. 100 years). Confirmation is needed that such durability can be achieved, especially to show that the progression of corrosion of the reinforcement is slow enough. Ten MSE walls around Florida were instrumented (electrical connections were made through the concrete covers to the buried elements) between 1996- 1998 and used to survey corrosion rates of galvanized strip or mesh soil reinforcements. Initial estimates of corrosion-related durability were obtained at that time, indicating a good prognosis for long term durability. The objective of the research in this thesis was to obtain additional indications of the durability of reinforcements in MSE walls in Florida so as to perform a more reliable projection of future performance. Corrosion behavior was measured at the same locations as the initial survey by electrochemical nondestructive tests and by destructive tests. The nondestructive testing consisted of half-cell potentials, polarization resistance measurements, and electrochemical impedance spectroscopy. Corrosion rates reported in this thesis are based upon polarization resistance measurements. The destructive testing consisted of soil extraction and hardware extraction. Hardware extraction enabled independent verification of estimates of electrochemical corrosion rate. Analysis of extracted soil verified that soil composition was within construction specifications. The data from the current survey were also used to further improve prediction of corrosion. The present series of evaluations confirm that the structures are performing as desired based upon the updated model projection of future corrosion.

Download or read book Corrosion Protection of Reinforcing Steels written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2009-01-01 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has long been recognised that corrosion of steel is extremely costly and affects many industry sectors, including concrete construction. The cost of corrosion of steel reinforcement within concrete is estimated at many billions of dollars worldwide. The corrosion of steel reinforcement represents a deterioration of the steel which in turn detrimentally affects its performance and therefore that of the concrete element within which it has been cast. A great amount of work has been undertaken over the years concerning the prevention of corrosion of steel, including the application of coatings, which has included the study of the process of corrosion itself, the properties of reinforcing steels and their resistance to corrosion as well as the design of structures and the construction process. The objective of fib Bulletin 49 is to provide readers with an appreciation of the principles of corrosion of reinforcing steel embedded in concrete and to describe the behaviour of particular steels and their coatings as used to combat the effects of such corrosion. These include galvanised reinforcement, epoxy coated reinforcement, and stainless reinforcing steel. It also provides information on the relative costs of the materials and products which it covers. It does not deal with structure design or the process of construction or with the post-construction phase of structure management including repair. It is hoped that it will nevertheless increase the understanding of readers in the process of corrosion of reinforcing steels and the ability of key materials and processes to reduce its harmful effects.

Download or read book Corrosion of Reinforcing Steel in Concrete written by D. E. Tonini and published by ASTM International. This book was released on 1980 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Galvanized Steel Corrosion on the Integrity of Concrete written by Zuo Quan Tan and published by . This book was released on 2007 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The major concern regarding the use of hot-dip galvanized (HDG) steel as reinforcement in concrete has been the high rate of corrosion experienced by the zinc during the first hours in the fresh, wet, and highly alkaline concrete. The present work was aimed at clarifying three issues associated with these concerns. The first involves the metallurgical phases at the surface of the zinc coating. The concentration of zinc at the surface is a function of processing procedures, surface treatment, and exposure to weathering. Differences in the coating surface composition influence the corrosion behaviour of HDG steel reinforcing bars when they are embedded in concrete. The second issue involves the increasing use of supplementary cementing materials in concrete, which change the chemistry of the concrete pore fluid, and also influence the corrosion. The third issue is that the initial corrosion is accompanied by hydrogen evolution, which could increase the pore volume of adjacent cement and thereby, decrease the bond stress between the concrete and the steel. In order to limit the hydrogen evolution, a chromate layer is applied after galvanizing. The results of the project have demonstrated that, during zinc corrosion in ordinary Portland cement (OPC) concrete, calcium hydroxyzincate formed on untreated HDG steel provided sufficient protection against corrosion. Therefore, it is concluded that treating HDG rebar with dilute chromic acid is unnecessary as a method of passivating zinc.

Download or read book Texas Transportation Researcher written by and published by . This book was released on 1995 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Materials for the New Millennium written by Ken Pin Chong and published by . This book was released on 1996 with total page 1494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metals Abstracts written by and published by . This book was released on 1996 with total page 1650 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Corrosion Susceptibility of Internally Reinforced Soil Retaining Structures written by S. Frondistou-Yannas and published by . This book was released on 1985 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Testing Aggregate Backfill for Corrosion Potential written by Zachary Brady and published by . This book was released on 2016 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Kansas Department of Transportation (KDOT) has designed and constructed numerous mechanically stabilized earth (MSE) walls to support new and expanded highway projects throughout Kansas. MSE walls often contain galvanized steel strips as the mechanical reinforcement within layers of specified backfill material. Inclusion of these strips creates a stronger composite material connected to a visually appealing wall facing, but galvanized steel reinforcement is potentially vulnerable to corrosion. Corrosivity of MSE backfill is typically characterized using electrical resistivity among other properties. KDOT currently uses the American Association of State Highway and Transportation Officials (AASHTO) Standard T 288 (2012) to calculate the resistivity of MSE backfill. There is concern that this method may not reflect field conditions well, and thus may mischaracterize the corrosivity of backfill. AASHTO T 288 tests were conducted as a part of this research, and the condition of the samples at the time of testing was not consistent with expected field conditions. A new procedure has been proposed that appears to more accurately simulate field conditions. This new procedure (ASTM C XXX-XX) has been extensively tested and compared with AASHTO T 288 in this experimental study. The proposed ASTM test simulated expected field conditions more accurately than the AASHTO T 288 test. Results also appear to indicate the need for a larger resistivity box to accurately characterize the corrosivity of larger aggregates. Preliminary recommendations for box geometry are 8:1 minimum electrode spacing to maximum particle size and 3:1 minimum height to maximum particle size. It was also observed that increasing the number of soak/drain cycles of the material resulted in a substantial increase in resistivity.

Download or read book ASTM Special Technical Publication written by and published by . This book was released on 1985 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Galvanized steel reinforcement in concrete written by Stephen R. Yeomans and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Corrosion Behavior of Galvanized Steel Reinforcements in MSE Walls in the Presence of Soil Organics written by Claudia Aide Soriano Vazquez and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Corrosion Protection of Steel Reinforcement in Concrete and Tentative Recommendations for Use of Galvanized Steel Reinforcement written by B. Bresler and published by . This book was released on 1969 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plating and Surface Finishing written by and published by . This book was released on 1994 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: