Possible Modifications to the Accelerated Mortar Bar Test (ASTM

128 Pages·2013·3.49 MB·English

Possible Modifications to the Accelerated Mortar Bar Test
(ASTM C1260)
by
Farideh Golmakani
A thesis submitted in conformity with the requirements
for the degree of Master of Applied Science
Department of Civil Engineering
University of Toronto
© Copyright by Farideh Golmakani 2013
Possible Modifications to the Accelerated Mortar Bar Test
(ASTM C1260)
Farideh Golmakani
Master of Applied Science
Department of Civil Engineering
University of Toronto
2013
Abstract
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.

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Dedications
I would like to dedicate this dissertation to my parents Mina Rezaee and Hamid Reza
Golmakani, whom I owe all my achievements to. Mom and Dad, I have been tremendously
fortunate to have you and your unconditional love and support throughout my life.

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Acknowledgements
Mainly, I would like thank my supervisor, Prof. Hooton, for his invaluable support and guidance.
Prof. Hooton, you are a true inspiration to me.
I would like to express my great appreciation to Olga Perebatova, for her precious and tireless
assistance in the lab. Also, much gratitude goes to Prof. Peterson for all of his advice and for
providing North Star aggregates used in the experiments.
A special thank to the Ministry of Transportation of Ontario for supplying me with the Spratt and
Sudbury aggregates. Also, thank you to Ministry of Transportation of Texas for the Adamcek
and Wright aggregates.
Last, but not least, I am very grateful of my friends and fellow graduate students for their
spiritual support.

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Table of Contents
Dedications .................................................................................................................................... iii 
Acknowledgements ........................................................................................................................ iv 
Table of Contents .............................................................................................................................v 
List of Tables ............................................................................................................................... viii 
List of Figures ................................................................................................................................ ix 
List of Appendices ......................................................................................................................... xi 
Chapter 1 Introduction .....................................................................................................................1 
1  Introduction .................................................................................................................................1 
1.1  Background ..........................................................................................................................1 
1.2  Objectives and Scope of Research .......................................................................................2 
1.3  Organization .........................................................................................................................3 
Chapter 2 Alkali-Silica Reaction and AMBT ..................................................................................5 
2  Alkali-Silica Reaction and AMBT ..............................................................................................5 
2.1  Mechanism ...........................................................................................................................5 
2.1.1  The dissolution of the reactive silica .......................................................................5 
2.1.2  Formation of ASR gel ..............................................................................................7 
2.1.3  Expansion of Gel ......................................................................................................9 
2.2  Laboratory Testing Methods ..............................................................................................10 
2.3  The Accelerated Mortar Bar Test ......................................................................................11 
2.4  Previous Proposed Modifications to AMBT......................................................................13 
Chapter 3 Permeability and Loss on Ignition ................................................................................18 
3  Permeability and Loss on Ignition ............................................................................................18 
3.1  W/C, Degree of Hydration, and Porosity ...........................................................................18 
3.2  Porosity and Permeability ..................................................................................................22 
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3.3  Non-evaporable water content as a measure of degree of hydration .................................25 
3.3.1  Degree of hydration ...............................................................................................25 
3.3.2  Loss on ignition Procedure ....................................................................................26 
3.3.3  Ultimate Non-evaporable Water Content ..............................................................30 
Chapter 4 Experimental Program ...................................................................................................32 
4  Experimental Program ..............................................................................................................32 
4.1  Overview ............................................................................................................................32 
4.2  Materials ............................................................................................................................33 
4.2.1  Cementitous Materials ...........................................................................................33 
4.2.2  Water ......................................................................................................................33 
4.2.3  Aggregates .............................................................................................................34 
4.3  Mix designs ........................................................................................................................40 
4.4  Casting and Curing Procedures ..........................................................................................41 
4.4.1  Paste Tests ..............................................................................................................41 
4.4.2  Mortar Tests ...........................................................................................................44 
4.5  Test Methods ......................................................................................................................47 
4.5.1  Paste Tests ..............................................................................................................47 
4.5.2  Mortar Tests ...........................................................................................................49 
4.6  Data processing ..................................................................................................................52 
4.6.1  Paste Tests ..............................................................................................................52 
4.6.2  Mortar Tests ...........................................................................................................56 
Chapter 5 Results and Discussion ..................................................................................................57 
5  Results and Discussion ..............................................................................................................57 
5.1  Maturity..............................................................................................................................57 
5.1.1  Water to cement ratio .............................................................................................57 
5.1.2  Water curing duration ............................................................................................67 
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5.2  Temperature .......................................................................................................................79 
Chapter 6 Conclusions and Recommendations ..............................................................................88 
6  Conclusions and Recommendations .........................................................................................88 
6.1  Conclusions ........................................................................................................................88 
6.2  Recommendations for Future Research .............................................................................89 
References ......................................................................................................................................90 
Appendix A: Non-evaporable water content, Degree of Hydration, Porosity, and Solid to
space ratio Data of Pastes ........................................................................................................102 
Appendix B: AMBT Expansion and Mass Change Data .............................................................105 

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List of Tables
Table 2-1: AMBT Standard Test Methods ................................................................................... 12 
Table 3-1: Drying Methods ........................................................................................................... 26 
Table 4-1: Chemical and Physical Analysis of Cement ................................................................ 33 
Table 4-2: Relative Density of the Aggregates ............................................................................. 34 
Table 4-3: Aggregate Description, Reactive Component, Field Performance, and AMBT
Classification................................................................................................................................. 34 
Table 4-4: Granulometry of Aggregates ....................................................................................... 35 
Table 4-5: Paste Mix Designs ....................................................................................................... 40 
Table 4-6: Mix design for Mortar Tests ........................................................................................ 41 
Table 4-7: Ultimate Non-evaporable Water Content based on Freeze-drying. ............................ 55 
Table 5-1: Non-evaporable Water Content, Degree of Hydration, and Solid to Space ratio for
mixes with various W/C ................................................................................................................ 58 
Table 5-2: Average 14d AMBT Expansions for different W/C and Aggregates ......................... 60 
Table 5-3: Average 14d AMBT Expansions for Sudbury and Spratt ........................................... 60 
Table 5-4: Non-evaporable Water Content, Degree of hydration, and Solid to Space ratio for
pastes with various slag replacements .......................................................................................... 69 
Table 5-5: Average 14d AMBT expansions of samples water cured for 1d, 2d, and 3d. ............. 71 
Table 5-6: Average 14d AMBT expansions of Sudbury and Spratt samples water cured for
different durations. ........................................................................................................................ 72 
Table 5-7: Average 14d AMBT expansions vs average 28d expansions of samples maintained at
60˚C............................................................................................................................................... 79 
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List of Figures
Figure 2-1: Formation of negatively charged silica oxide bridges, based on the theory given in
[Dent Glasser & Kataoka, 1982]. .................................................................................................... 7 
Figure 2-2: Silica oxide bridges bind the cations. ........................................................................... 9 
Figure 2-3: Flow Chart for ASR Laboratory Standard Testing Methods ..................................... 11 
Figure 3-1: Powers’ Model (Powers et al., 1957) ......................................................................... 23 
Figure 4-1: Crushing Aggregates. ................................................................................................ 36 
Figure 4-2: Sieving Aggregates. ................................................................................................... 37 
Figure 4-3: Washing Aggregates. ................................................................................................. 38 
Figure 4-4: Drying and Proportioning Aggregates. ..................................................................... 39 
Figure 4-5: Paste Tests Preparation. ............................................................................................. 42 
Figure 4-6: Paste Tests Mixing, Molding, and Moist curing. ....................................................... 43 
Figure 4-7: Lime water preparation. ............................................................................................. 44 
Figure 4-8: Casting Preparation for Mortar Tests. ........................................................................ 45 
Figure 4-9: Mixing, Molding, and Moist curing of Mortar Tests. ................................................ 46 
Figure 4-10: Freeze Drying Paste Cubes. ..................................................................................... 48 
Figure 4-11: Crushing and Freeze Drying Crushed Paste. ........................................................... 49 
Figure 4-12: Demoulding and Subsequent Readings.................................................................... 50 
Figure 4-13: NaOH Solution Preparation. .................................................................................... 51 
Figure 5-1: Length change vs Time and W/C for Sudbury Aggregate ......................................... 61 
Figure 5-2: Length change vs Time and W/C for Spratt Aggregate ............................................. 62 
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Figure 5-3: Length change vs Time and W/C for Paris sand ........................................................ 63 
Figure 5-4: Length change vs Time and W/C for North Star sand ............................................... 64 
Figure 5-5: Length change vs Time and W/C for Adamcek aggregate ........................................ 65 
Figure 5-6: Length change vs Time and W/C for Wright aggregate ............................................ 66 
Figure 5-7: Non-evaporable Water Content vs 80˚C Water Curing Duration for pastes cast with
different W/C ................................................................................................................................ 67 
Figure 5-8: Non-evaporable Water Content vs 80˚C Water Curing Duration for pastes with
various slag replacements ............................................................................................................. 68 
Figure 5-9: Length change vs Time and Water Curing Duration for Sudbury Aggregate ........... 73 
Figure 5-10: Length change vs Time and Water Curing Duration for Spratt Aggregate ............. 74 
Figure 5-11: Length change vs Time and Water Curing Duration for Paris Sand ....................... 75 
Figure 5-12: Length change vs Time and Water Curing Duration for North Star Sand ............... 76 
Figure 5-13: Length change vs Time and Water Curing Duration for Adamcek Aggregate ....... 77 
Figure 5-14: Length change vs Time and Water Curing Duration for Wright Aggregate ........... 78 
Figure 5-15: Length change vs Time and Temperature for Sudbury Aggregate .......................... 81 
Figure 5-16: Length change vs Time and Temperature for Spratt Aggregate .............................. 82 
Figure 5-17: Length change vs Time and Temperature for Paris Sand ........................................ 83 
Figure 5-18: Length change vs Time and Temperature for North Star Sand ............................... 84 
Figure 5-19: Length change vs Time and Temperature for Adamcek Aggregate ........................ 85 
Figure 5-20: Length change vs Time and Temperature for Wright Aggregate ............................ 86 
Figure 5-21: Length change vs Time for all aggregates maintained under different temperatures.
....................................................................................................................................................... 87
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