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You searched for subject:(ASTM C 1260). Showing records 1 – 2 of 2 total matches.

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University of Toronto

1. Golmakani, Farideh. Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260).

Degree: 2013, University of Toronto

The Accelerated Mortar Bar test (AMBT) is rapid, reproducible, and perhaps the most widely used technique for examining the potential alkali-silica reactivity of aggregates. Unfortunately, this test is often unreliable as it may identify non-reactive aggregate as reactive and vice versa. With the aim of improving the accuracy of AMBT, two modifications to the current procedure were evaluated: 1) the maturity of mortar bars prior to alkali hydroxide exposure and 2) reduction of the storage temperature. The original and modified versions were performed on six aggregates with alkali-silica reactive (ASR) components, and their expansions and ASR classifications were compared. Results show that increasing the maturity had no significant impact on expansions. However, modifying the storage temperature to 60˚C and extending the period of testing to 28 days can be very effective in terms of more reliably identifying the existing falsely identified aggregates.

MAST

Advisors/Committee Members: Hooton, Robert Douglas, Civil Engineering.

Subjects/Keywords: Alkali-Silica Reaction; Accelerated Mortar Bar Test; ASTM C 1260; CSA A23.2-25A; 0543

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Golmakani, F. (2013). Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260). (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/35608

Chicago Manual of Style (16th Edition):

Golmakani, Farideh. “Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260).” 2013. Masters Thesis, University of Toronto. Accessed June 18, 2019. http://hdl.handle.net/1807/35608.

MLA Handbook (7th Edition):

Golmakani, Farideh. “Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260).” 2013. Web. 18 Jun 2019.

Vancouver:

Golmakani F. Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260). [Internet] [Masters thesis]. University of Toronto; 2013. [cited 2019 Jun 18]. Available from: http://hdl.handle.net/1807/35608.

Council of Science Editors:

Golmakani F. Possible Modifications to the Accelerated Mortar Bar Test (ASTM C1260). [Masters Thesis]. University of Toronto; 2013. Available from: http://hdl.handle.net/1807/35608


Clemson University

2. Math, Sujay. Effect of selected parameters on aggregate reactivity in Accelerated Mortar bar test method: Aggregate Size & Deicers.

Degree: MS, Civil Engineering, 2011, Clemson University

Abstract Alkali Silica Reaction (ASR) is a chemical reaction between reactive siliceous aggregates and the alkali hydroxides present in the pore solution of hydrated cement paste in concrete. The chemical reaction produces ASR gel that is hygroscopic in nature and is volumetrically unstable in the presence of moisture. Expansion resulting from the swelling of the gel creates tensile stresses in the concrete leading to cracking and distress. While ASR distress has been known to occur in concrete for over last 70 years, there has been an increase in the frequency of this distress in recent years. This is primarily due to a combination of four factors. Firstly, marginal aggregates are increasingly being used in concrete due to shortage of good quality aggregate, particularly in urban locations where development of new source of aggregates is restricted. Secondly, the alkali content of cement has gradually increased over last two decades due to increased environmental regulations on the emissions from cement industries. Thirdly, the existing test methods employed to evaluate the reactivity of aggregates are not entirely effective with different rock types. Lastly, the development and use of new types of alkaline chemical deicing agents on concrete has created a hitherto unanticipated situation. Among the first defenses to combat ASR is an effective test method to screen reactive aggregates. Screening of aggregates for their reactive nature has been conducted by several laboratory test methods available in the concrete industry, but none of them have proven to be very reliable to assess the reactive nature of all the aggregate types accurately. Among the several tests available, the Accelerated Mortar Bar Test (AMBT) method is widely used, followed by Concrete Prism Test (CPT). The AMBT method suffers from high variability in test results and has the potential to mischaracterize a good performing aggregate as reactive. Also, recently a variant of this test method (EB-70 protocol) to evaluate impact of deicing chemicals on aggregate reactivity was introduced through Federal Aviation Administration (FAA). However, poor correlation between the results of deicer-based AMBT and the standard AMBT has required additional investigation to develop better test procedures. The CPT method is more reliable than AMBT method, however it take a long time to complete and is considered to impractical from field perspective. This thesis describes research conducted to improve existing test methods to better characterize the aggregate reactivity. The three principal objectives of this study are: (1) Determine the impact of re-sizing coarse aggregates to meet the gradation requirements of ASTM C 1260 test method in assessing the reactivity of the aggregates. (2) Develop a better test method to evaluate the reactivity of aggregate in presence of potassium acetate deicing chemical (3) Decrease the length of ASTM C 1293 test method in… Advisors/Committee Members: Rangaraju, Dr. Prasad, Putman , Dr. Bradley, Klotz , Dr. Leidy.

Subjects/Keywords: Accelerated Mortar Bar Test Method (ASTM C 1260); Aggregate Size effects; Alkali Silica Reaction in concrete; Deicer effects; Petrological Investigations; pH of pore solution; Civil Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Math, S. (2011). Effect of selected parameters on aggregate reactivity in Accelerated Mortar bar test method: Aggregate Size & Deicers. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1113

Chicago Manual of Style (16th Edition):

Math, Sujay. “Effect of selected parameters on aggregate reactivity in Accelerated Mortar bar test method: Aggregate Size & Deicers.” 2011. Masters Thesis, Clemson University. Accessed June 18, 2019. https://tigerprints.clemson.edu/all_theses/1113.

MLA Handbook (7th Edition):

Math, Sujay. “Effect of selected parameters on aggregate reactivity in Accelerated Mortar bar test method: Aggregate Size & Deicers.” 2011. Web. 18 Jun 2019.

Vancouver:

Math S. Effect of selected parameters on aggregate reactivity in Accelerated Mortar bar test method: Aggregate Size & Deicers. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2019 Jun 18]. Available from: https://tigerprints.clemson.edu/all_theses/1113.

Council of Science Editors:

Math S. Effect of selected parameters on aggregate reactivity in Accelerated Mortar bar test method: Aggregate Size & Deicers. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1113

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