Performance of chemical substance inhibitors on the surface between steel rebar and concrete

2021 ◽  
pp. 1-19
Author(s):  
Ahmed Elshami ◽  
Stéphanie Bonnet ◽  
Abdelhafid Khelidj ◽  
Mohammad Farouk Abdelmagied
Keyword(s):  
Chemical Substance ◽  
Steel Rebar

Studies on Thalidomide as a Cause of Congenital Malformations

1963 ◽  
Vol 02 (02) ◽  
pp. 49-51 ◽  
Author(s):  
K. Knapp ◽  
W. Lenz
Keyword(s):  
Federal Republic ◽  
Congenital Malformations ◽  
Chemical Substance ◽  
Federal Republic Of Germany ◽  
Virus Diseases ◽  
Many Sources

SummaryIn 1961 an increase in certain congenital malformations was noticed in various parts of the Federal Republic of Germany. From the outset, it seemed very probable that a single cause was responsible, since, although these malformations varied, they appeared to belong to one and the same syndrome. For general reasons, such causes as radioactivity, contraceptives, attempted abortions or virus diseases did not provide an acceptable explanation. The epidemiology was, however, suggestive of some chemical substance taken orally.After thalidomide had been indicated in several histories, suspicion of that drug was aroused and, within one week, intake of it could be proved or was found to be very likely in 17 out of 20 cases, while in the remaining cases it could not be excluded. Though this first result was highly significant, we were at first reluctant to incriminate thalidomide definitely, because there was still some doubt about the reliability of the histories. But within a few weeks, the thalidomide aetiology received support from many sources. Specific studies on limited material are sometimes superior to extensive, broadly planned investigations.

Positive effects of aligned steel fiber on bond behavior between steel rebar and concrete

2020 ◽  
Vol 114 ◽  
pp. 103828
Author(s):  
Xuhui Zhang ◽  
Wei Zhang ◽  
Cuodong Cao ◽  
Fu Xu ◽  
Caiqian Yang
Keyword(s):  
Steel Fiber ◽  
Bond Behavior ◽  
Positive Effects ◽  
Steel Rebar

scholarly journals Effect of Electrical Injection of Corrosion Inhibitor on the Corrosion of Steel Rebar in Chloride-Contaminated Repair Mortar

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
The Huyen Nguyen ◽  
Tuan Anh Nguyen ◽  
Thien Vuong Nguyen ◽  
Van Khu Le ◽  
Thi Mai Thanh Dinh ◽  
...  
Keyword(s):  
Current Density ◽  
Cement Mortar ◽  
Tetrabutylammonium Bromide ◽  
Electrical Current ◽  
Corrosion Current ◽  
Sodium Borate ◽  
Apparent Diffusion Coefficients ◽  
Steel Rebar ◽  
Repair Mortar ◽  
Vis Spectroscopy

The electrical rehabilitation treatments of repair mortar were performed with tetrabutylammonium bromide salt (TBAB) at an electrical current density of 5 A/m2, using two electrolytes (0.1 M NaOH and 0.1 M Na3BO3solutions), and for two time periods (1 and 4 weeks), respectively. The average organic cation-based inhibitor’s concentration in cement mortars before and after this treatment was quantified using the UV-Vis spectroscopy. The experimental results reveal that the EICI treatment with 0.1 M Na3BO3was more effective in injecting the inhibitor and in improving the chloride penetration resistance and compressive strength of the mortar, relative to using 0.1 M NaOH as electrolyte. In this case, after the 4-week EICI treatment, [TBA+] contents were 2.3 % and 2.4% by mass of cement mortar for uncontaminated and salt-contaminated mortars, respectively. After the 4-week EICI treatment, the apparent diffusion coefficients of chloride anion in cement mortar were decreased by 40% from 1.52 × 10−10 m2/s. The EICI treatment was able to halt the chloride-induced corrosion of the steel rebar by promoting its passivation. The 2-week EICI treatment using sodium hydroxide and sodium borate solutions decreased the corrosion current density of the rebar by 77.8% and 78.5%, respectively, approximately two months after the treatment.

The Weathering of Mafic Rocks by Lichens

1993 ◽  
Vol 25 (3) ◽  
pp. 285-297 ◽  
Author(s):  
P. Adamo ◽  
A. Marchetiello ◽  
P. Violante
Keyword(s):  
Oxalic Acid ◽  
Chemical Substance ◽  
Mineral Surfaces ◽  
Secondary Products ◽  
Mafic Rocks ◽  
Crustose Lichens ◽  
Parmelia Conspersa

AbstractThe weathering phenomena resulting from the growth of six foliose and crustose lichens (Parmelia subrudecta, Xanthoria ectaneoides, Parmelia conspersa, Aspicilia radiosa, Caloplaca sp. and Ochrolechia parella) on three mafic rocks have been studied. The bioweathering results in more or less extensive fragmentation and corrosion of the mineral surfaces immediately beneath the lichen thalli and in the formation, in the thallus or at the rock-lichen interface, of secondary products. The significant amounts of whewellite found in all interfaces, and the bipiramids of weddellite detected at the serpentine rock-Ochrolechia parella interface, suggest that the oxalic acid secreted by the mycobiont is the chemical substance principally involved. The capacity of the lichens to alter their rock substrata does not appear to be related to their thallus morphology.

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