Alkali-Silica Reactivity (ASR)Aggregate Testing: Is There a Better, Quicker, and More Reliable Method?

Current Aggregate Tests Originate from 1947

• Mielenz, Greene, and Benton American Concrete Institute (ACI), 1947

• Sprague Hun et al. (ACI), 1948• 1N Sodium Hydroxide 80 °C• Measured Mortar Bar Expansion

• ASTM C 289 — Test has poor reliability. • Petrography — Tool is useful but depends

on skill of petrographer.• ASTM C 227 — Test can result in leaching.• ASTM C 1260 — Test can be overly severe.• ASTM C 1293 — Testing period is lengthy

and can result in leaching; test is unsuitable for the evaluation of job mix design.

Aggregates

Mortar

Concrete

Current ASR Test Methods

ASTM – American Society for Testing Materials

ASTM C1778 – 16

Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete

Reprinted, with permission, from Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reactionin Concrete, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.

“Is my particular job mix design reactive?”

Yes/No

Add Supplementary Cementitious Materials (SCMs)

TFHRC Chemical ASR Test

Standard Methods • ASTM 1260 — Rapid but inaccurate.

• ASTM 1293 — More accurate but takes 1 to 2 years for results.

Source: FHWA

Source: FHWA

TFHRC Test – Pure Chemistry

• Mill report.• Mix design.• 5-gram

aggregate.• 21 days.

3.125 gRet. #50(297 µm)

1.875 gRet. #100(149 µm)

Source: FHWA

TFHRC Chemistry LaboratoryResearch Since 2009

• Researchers in TFHRC’s Chemistry Lab studied the chemistry of ASR gels. Findings include:– ASR gel has no unique composition.– Chemical composition of gels affect structure, which affects

expansion.– The Raman Spectroscopy study helped identify what chemical

parameters are important in a test.

Must Test The Job Mix• Meaningless to test aggregate alone.• Thirty job mixes tested per person per week.• Only 1 measurement is needed at the end of 21

days.

ASRTESTS

Aggressive Environment Possibility

to test job mix

Realistic concrete

pore solution

Testing period

Mirrorfield

performance

TestingEfficiencyAlkali

conc. Temp.

ASTM 1260 Yes Yes No No 14

days No Medium

ASTM1293 Yes No No No 1 year Mostly Low

TFHRC Chemical

TestNo No Yes Yes 21

days Yes High

Comparison of Accelerated ASR Tests

conc. - concentration

Results: Correlation with Physical ExpansionExpansion

No ExpansionFalse Positive

False Negative

Source: FHWA

Correlation with Physical Expansion ASTM C1260Expansion

No ExpansionFalse Positive

False Negative

MassDOT

TxDOT

Source: FHWA

Correlation with Physical Expansion ASTM 1293

Expansion

No ExpansionFalse Positive

False Negative

Source: FHWA

Correlation with Physical Expansion - TFHRC TestExpansion

No ExpansionFalse Positive

False Negative

Source: FHWA

Calibration of TFHRC ASR Test• Field cases, block farms, or structures:

– Aggregate samples 500 g.– Cement samples 50 g or mill certificate.– Mix design.– Expansion data (new and historical).

• The test can accurately detect highly and nonreactive coarse aggregates.

• Intermediate reactive aggregates are more challenging to detect.

• Comparison of lab test results with known field block expansion shows good correlation.

TFHRC Rapid Chemical ASR Test

Terry ArnoldSenior Research ChemistFederal Highway Administration (FHWA)Turner-Fairbank Highway Research Center (TFHRC)Office of Infrastructure Research and Development (R&D)6300 Georgetown PikeMcLean, Virginia 22101 Terry.Arnold@dot.gov202–493–3305

We are looking for field cases and block farm data to further populate the calibration charts.

Contact Us!

The Way Forward