Effect of Alkali-Silica Reaction on Cement-Based Products Containing Trass (Using A New Method)

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Effect of Alkali-Silica Reaction on Cement-Based Products Containing Trass (Using A New Method)

ارائه دهنده: Provider: Afshin Mohammadi Bolban Abad

اساتید راهنما: Supervisors: Mahmood Nili (Ph.D) - Ebrahim Ghiasvand (Ph.D)

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: دکتر سیدمهدی حسینیان - دکتر محمد شوشتری

زمان و تاریخ ارائه: Time and date of presentation: November, 18, 2020

مکان ارائه: Place of presentation:

چکیده: Abstract: Existence of reactive silica reacts with the alkalis of cement and produces deleterious gel. It's called alkali-silica reaction (ASR) due to the reaction between alkalis and the reactive silica. ASR is one of the most deleterious durability problems in all over the world. One of the main challenges in the field of ASR is the test method for evaluating the reactivity of aggregates. Different methods have been introduced for it, as ASTM C1260 and ASTM C1293. The majority of these methods evaluates the reactivity of aggregates by measuring the changes in the length of concrete or mortar samples. In this study has been tried to evaluate the ASR in cement-based products containing trass in two different kind of aggregates with new method. In this research main standard test method (ASTM C1260 and accelerated ASTM C1293) have been used two for evaluating the reactivity of used aggregates. Also, some kinds of the mechanical properties of concrete (compressive, flexural, tensile and strength and electrical resistivity) measured until 1, 3 and 6 month, which they had been stored in accelerated ASTM C1293 condition. Likewise, the amount of electrical resistivity of them measured until 6 months. Based on the results, it can be concluded that the results and behavior of aggregates in short and long-term test methods were different, and ASTM C1260 presented false results in some cases. As well, the mechanical properties reduced due to the occurrence of ASR. Among the studied mechanical properties, ASR had the highest effect on the tensile, flexural and compressive strength, respectively. New introduced test method (electrical resistivity) had a good correlation with the results of ASR expansion in non-trass samples. Also, samples which contained trass had a significant increasing in their amount of electrical resistivity, due to the pozzolanic reaction. Although, their expansions increased, but their electrical resistivity had high amounts. Key Words: Alkali-silica Reaction (ASR), mechanical properties, trass, compressive strength, flexural strength, tensile strength, electrical resistivi

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