This study aims to examine the relationship between the corrosion rate of longitudinal tensile steel bars and the maximum flexural strength of reinforced concrete RC beams. The study's methodology is designed to show the structural behavior of corroded and non-corroded RC beams, such as ultimate load, deflection, stiffness, crack patterns, and failure mode. Three rectangular beams were cast with dimensions (150× 200 ×1200) mm, and all specimens have the same amount of longitudinal and transverse reinforcement and the same concrete strength. The major parameter is the theoretical mass loss level due to corrosion (0, 10, 15) %. Electrochemical technique was used to accelerate the corrosion in the longitudinal tensile bars. All RC beams were tested under four-point monotonic loading. The test results confirm that the cracking load in corroded beams decreased by 25% comparative to the non- corroded beam. The increase of the percent of corrosion experimental mass loss by 8.25 and 14.15 % decreased the ultimate load by about 14 % and 27%, respectively. This reduction coincided with the decrease in deflection values in mid-span for the ultimate load, which decreased by 53.9% and 46.3%. However, the flexural stiffness was reduced by 13.4 and 15.6% for corroded beams with mass loss (8.25 and 14.15), respectively, compared to the control beam (non-corroded RC beam).
In this study , Silicon and Aluminum with and without cerium were simultaneously co-deposited by diffusion into austenitic stainless steel (AISI 316L) substrates, by a single-step packcementation process. Cyclic hot corrosion tests were conducted on coated and uncoated austenitic stainless steel alloy with 50wt.% NaCl+50wt.%Na2So4 deposits at 750C° for 120h at 10h cycle. The results show that the hot corrosion resistance of both coated stainless steels, was significantly improved as compared with the uncoated steels. The scale formed on coated stainless steel after oxidation in mixture environment was consisted of NiAl2O4, NiFe2O4 and NiCr2O4. Optical metallography (LOM) and X-ray diffraction(XRD) was used to characterize the resulting coating and cyclic hot corrosion structures.
A steam boiler is a metal vessel in which a particular liquid is heated to steam. Steam is used in the production of energy in several areas as most boilers convert water to steam used in heating buildings and others. Steam boilers are exposed to corrosion and sediment as a result of salts dissolved in water, which may lead to increased temperature inside the boiler and thus the boiler explosion. The research included finding a suitable way to solve the problem of sedi-ment and corrosion by adding suitable chemicals to get rid of the dissolved salts inside the water and maintain steam boiler. To control this problem, the control system is designed to control the amount of salts in the water in the steam boiler using PLC.
The corrosion of reinforcement iron is one of the dangerous problems in middle and west of Iraq and Arabian gulf which is needed to large investigations because of increasing of chloride salts in soil and ground water and rising of temperature at summer which encourage of finding the shrinkage cracks in their two types : Plastic and drying shrinkage . cracks are easy way for harmful ions present at soil and ground water to enter through reinforced concrete making damage for protection film a rounding rein forced iron and led to rust with cracks in concrete cover a rounding rein forced iron added to its may be to cause structural damage in members of rein forced concrete because of absence of a adhesive between concrete and steel leading to structural failure . This research presents study for this problem and knowing their causes and methods to reduce it. Experimental work show that the concrete exposed to chlorides leads to decreasing in density with ratio (1.5%) and decreasing in flextural strength with ratio (138%) at age (28) day .