To study the corrosion failure mechanism of tunnel lining structure subjected to sulfate attack and dissolved corrosion, site investigation was carried out on a diseased in Chongqing. The products were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) Fourier transform infrared (FTIR) spectroscopy. results showed that had been exposed ...

In the present work the internal sulfate attack on pastes made from pure clinker phases was studied. Two binders were produced: (a) a binder with 2% C3A and 18% C4AF content; (b) a binder with 10% C3A and C4AF content each. Gypsum was used as the sulfate bearing compound, while calcium carbonate added to differentiate the binders produced. The phases formed were identified by XRD analysis. The ...

Oxidation and hydration of sulfides in aggregate materials can yield to expansive reactions that affect the durability of concrete. This process is, in principle, independent from the potential alkali-aggregate reactivity, and the oxidation of the sulfide is the rate-limiting reaction. A model is presented to evaluate the kinetic evolution of expansion due to sulfide oxidation, and subsequent s...

In order to extend the recycling of waterworks sludge to engineering applications, this paper addresses the influence of nano-SiO2 on incinerated waterworks sludge ash (IWSA) cement paste attacked by sulfate. Tests were performed such as length measurement for volume change, compressive strength, weight loss, and micro-structural testing using scanning electron microscopy (SEM). The results ind...

Shotcrete is often in direct contact with groundwater containing sulfate. The resistance to sulfate attack of modern sprayed concretes produced non-alkali aluminate-based accelerators combination different cement types related their microstructure, transport properties, porosity and phase composition. A characterization these properties allows a comprehensive assessment the shotcrete identifica...

Elevated sulfate concentrations in industrial effluent can lead to a number of significant problems, the most serious of which is the corrosion of concrete sewers as a result of hydrogen sulfide induced biogenic sulfuric acid attack; hydrogen sulfide can also create odor nuisance problems. The most common treatment process for sulfate removal from wastewaters is to precipitate it as gypsum usin...

Construction and demolition wastes (C&DWs) have raised a large number of ecological environmental problems. Recycling C&DWs into arecycled concrete aggregate (RCA) will help save natural resources effectively reduce the negative impact C&DW on environment. Innovative pervious (IPC) can mitigate extreme weather disasters, such as rainstorms, overcome low strength poor durability trad...

recently, baghery et al. [1, 2] presented some attacks on two rfid protocols, namely yoon and jung et al. protocols, and proposed the improved version of them. however, in this note, we show that the improved version of the jung et al. protocol suffers from desynchronization attack and the improved version of the yoon's protocol suffers from secret disclosure attack. the success probabilit...

This paper presents a study on the behavior of concrete produced from multi-component blended cements. These blends were prepared by blending 20 percent to 60 percent ASTM Type I cement with the combination of Class C fly ash and clean coal ash. Two percent to four percent sodium sulfate anhydrite was added to the blends as a chemical activator. Tests were conducted on the prepared concrete for...