Reinforced mortar samples were exposed in humidity chambers with different relative humidity or exposed in cyclic moisture conditions.The rebars were in an "as received" condition meaning that the preexisting oxide scale were intact. The lowest chloride concentration that initiated corrosion was 1% Cl À by mass of cement, corrosion was then observed for samples exposed at 97% relative humidity. It is suggested that the corrosion rate decreases when samples are exposed to a relative humidity lower than 97%. The results indicate that threshold levels should be evaluated at rather humid conditions (97%) despite the fact that the maximum corrosion rate at higher chloride levels is observed in the interval 91-94%. For samples exposed to cyclic moisture conditions, a lower chloride concentration was needed to initiate corrosion compared to samples exposed in static moisture conditions.
The electrochemical properties of various iron oxide scales on steel exposed in saturated calcium hydroxide solutions were investigated. The iron oxide scales were manufactured by different heat treatments and grinding processes and characterized using X-ray diffraction and scanning electron microscope. The electrochemical properties of the scales were assessed by measuring the corrosion potential and using electrochemical impedance spectroscopy and potentiodynamic polarization curves. It was found that wustite and magnetite are less noble compared to hematite but are more effective as cathodic surfaces. The results show that the electrochemical properties of the mill scale can be an important contributing factor in the corrosion of steel in concrete.
<p>Bridge edge beams may take up to 60% of the life-cycle measure costs of a bridge and cause con- siderable user costs because of roadworks. The Swedish Transport Administration presented new edge beam solutions that could become better for the society in terms of cost. Stainless steel has been considered for enhanced durability, preventing expensive maintenance. The purpose of this paper is to motivate the use of stainless steel in the solutions proposed. A life-cycle cost analysis is carried out to evaluate the cost-efficiency of a concrete integrated edge beam with stainless and carbon steel reinforcement in a bridge project. The influence of the discount rate is addressed by a sensitivity analysis. Stainless steel is shown to lead to cost-efficient edge beam solutions. Low dis- count rates encourage using better quality designs with higher investment costs but lower life- cycle measure costs and user costs, which supports the use of stainless steel.</p>
Electroosmosis is an electrokinetic phenomena which is applied in some technical fields. It is also applied large scale for transport of moisture out of basements. We see the method of electroosmosis as an opportunity for solving moisture problems in basements. However, there is a need to develop both the technology for the method and the understanding about what to expect out of it. Better methods are needed to predict whether the method will work in a particular case.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.