Micro-Structure Studies of Concretes Containing Slag Against to Alkali-Silicate Reaction

نوع: Type: thesis

مقطع: Segment: Masters

عنوان: Title: Micro-Structure Studies of Concretes Containing Slag Against to Alkali-Silicate Reaction

ارائه دهنده: Provider: Mehran Ayoubi

اساتید راهنما: Supervisors: Ebrahim Ghiasvand

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Javad Taheri Nezhad, Seyed Mehdi Hosseinian

زمان و تاریخ ارائه: Time and date of presentation: 15/03/2022 11:30 AM

مکان ارائه: Place of presentation: آنلاین

چکیده: Abstract: In the last few decades, the alkaline reaction of aggregates (AAR) has been one of the major concerns of concrete industry operators in terms of durability and failure to pay attention to why this reaction occurs and lack of plans to prevent or treat its destructive effects, has led to costs. There is a burden on development projects. Due to the severity of the destruction of concrete elements due to this reaction, researchers refer to this phenomenon as concrete cancer. The alkaline silica reaction of aggregates (ASR) is known as the most significant type of alkaline reaction of aggregates due to its ubiquity in the world. Unfortunately, so far most researchers have studied the external signs of this phenomenon and less attention has been paid to microstructural studies. In addition, we know that the standards developed to identify the destructive effects of the alkaline-silica reaction are generally related to the macroscopic and large-scale sections of concrete, and no specific standard has been defined for microstructure studies. New methods of identifying and analyzing materials, such as scanning electron microscopy images, energy-scattering spectrometers, and X-ray diffraction analysis, can help researchers find out why this reaction occurs or analyze the causes of its prevention using certain materials. In the present study, using some advanced tools available in the country, the microstructure of slag-containing concretes (activated and inactivated with alkali) exposed to alkaline silica reaction of aggregates is intended to be studied. In order to achieve better results, other experiments such as expansion and compressive, flexural, tensile and electrical resistances have been performed. Because the occurrence of this destructive phenomenon is usually time consuming and its destructive effects appear in the long run (after about 10 to 15 years), in this study, the samples are placed in intensified conditions to accelerate the onset of symptoms of injury. For this purpose, the humidity and temperature of the storage environment of the samples has increased compared to normal conditions.

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