ACI 201 ACI 201 – Guide to Durable Concrete Guide to Durable Concrete Updates to AAR Chapter 5 Updates to AAR Chapter 5 Updates to AAR Chapter 5 Updates to AAR Chapter 5 Dr. Jason H. Ideker Assistant Professor Oregon State University Oregon State University
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ACI 201 ACI 201 –– Guide to Durable ConcreteGuide to Durable ConcreteUpdates to AAR Chapter 5Updates to AAR Chapter 5Updates to AAR Chapter 5Updates to AAR Chapter 5
Dr. Jason H. IdekerAssistant ProfessorOregon State UniversityOregon State University
OutlineOutline
Current version of ACI 201.2R-08, Ch 5Proposed revisions to ACI 201.2R-08
– Improved technical information on ASR and ACR– Test Methods – significant focus here
G id f t M i ASR f ll i AASHTO– Guidance for to Managing ASR following AASHTO approach - Benoit
– 47 references added47 references added– Summary
ACI 201.2R - 08Guide to Durable Concrete
Chapter 5: Alkali Aggregate Reaction•Types of Reactions•Evaluating Aggregates for Potential AAR•Preventive Measures
Preventive MeasuresEvaluating Aggregates forT f R ti Preventive MeasuresEvaluating Aggregates for Potential AAR
• Generally the tests of longer duration (e.g. the concrete prism test) are found to produce more reliable results than shorter duration highly aggressive( )
• Leaching (loss of alkalies)• Non-reactive aggregate issues
• Addition of new testing methodsg
Test Methods (2)Test Methods (2)
ASTM C 227 – Not recommended for identifying ASR or for cement aggregate combinationsexcessive leaching, trouble identifying slow reacting aggregates
ASTM C 289 N t d d f d t tiASTM C 289 – Not recommended for detecting potentially deleterious alkali-silica reaction in aggregate samplesaggregate samplesloss of reactive phases during crushing/sievingtemperatures during test change reactiontemperatures during test change reaction kinetics from that seen in field cocnrete
Test Methods (3)Test Methods (3)
Accelerated Concrete Prism Test – not a recommended test (NEW)excessive leaching due to temperaturemass loss (drying) of prisms, especially at early-
( t 7 d )age (e.g. up to 7 days)temperature (60C) changes reaction kinetics
sulfate drawn into solution preferrentiallynon-reactive fine aggregates play increasingly i l ( lk li l hi )important role (alkali leaching)
Test Methods (4)Test Methods (4)
ASTM C 1260 – caution given to following test method carefully (volume of soak solution, bars
f l i t t t d t th tof only one mixture type stored together, prevent evaporation, others)
Limit of 0.10% at 14 days recommended based on correlation to field performanceon correlation to field performance
Precautions given to false negativesPrecautions given to false negatives
Test Methods (5)Test Methods (5)
Concrete Prism Test – recommended test, most reliablereal-scale concrete tested, reduced leaching over mortar bar tests (ASTM C 227)d ti f 1 i till fduration of 1 or year is still of concern
Test Methods (6)Test Methods (6)
Concrete Microbar Test (NEW)40 x 40 x 160 mm prism2.5-5 mm aggregate1260 storage conditions14 day test with an expansion limit ~ 0.90%identified aggregates with false negatives in 1260gg g grecommend running in conjunction with ASTM C 1260
ACR Test MethodsACR Test Methods
Rock Cylinder Method (ASTM C 586)Chemical Composition (CSA A23.2-26A)Concrete Prism Test (ASTM C 1105)Concrete Microbar Test (CMT) (NEW)
2.5-5.0 mm aggregate and 5.0-10.0 mm28 day testing period for reactivityy g p yproposed limit of 0.10% at 28 days