Flatline the alkali-silica reaction (ASR) in concrete using pumice-blended cement…at a cost of just pennies per yard. Quantifiable performance backed by ASTM-standard research.

1. Mitigating the
Alkali-Silica Reaction
in Concrete
Pumice-Blended Cement is the
Ideal ASR Mitigator: Economical,
Consistent, and Highly Effective

2. Concrete Assassin
In regions with reactive aggregate,
the alkali-silica reaction (ASR) is a
relentless concrete assassin. There
is no way to stop ASR once such
chemically-flawed concrete has
been placed; no way to contain the
slow-motion explosion that map-
cracks the concrete and destroys
its structural integrity. An infected
structure is doomed to fail well
before its engineered lifespan.

3. Flatline ASR
The only way to beat ASR is to account for it in the
concrete mix design. That means specifying a
supplementary cementing material (SCM) that will
short-circuit the ASR chemical train wreck that is
triggered by the union of alkali and calcium
hydroxide (CH) from the Portland cement, silica
from the reactive aggregate, and moisture.

4. Pumice vs. Fly Ash
Fly ash has long been used as a
cheap by-product pozzolan in
concrete and has proven effective
at mitigating ASR. Tightening EPA
regulations on the coal-fired power
industry are disrupting the supply
of class F fly ash and driving the
need to identify a viable SCM
alternative.

5. The Ideal SCM
Pumice is a pozzolan, igniting a
secondary reaction within curing
concrete that consumes trouble-
making CH and repurposes it into
a chemical compound (CSH) that
fortifies and densifies the concrete
matrix. Win-win: ASR is flatlined
and overall concrete performance
is significantly improved.

6. CH is a deleterious compound that
fuels the alkali-silica reaction. more of this (CSH) means
stronger, denser concrete.
lessCHmeansthealkali-silicareactionisshort-circuited.
—AmericanConcreteInstitute
“
”
Pozzolans are made up of siliceous or siliceous and
aluminous materials that, in finely divided form, will react
with calcium hydroxide to form cementitious materials.

7. Quantifiable ASR-
Mitigating Performance
Backed by ASTM-standard
research, pumice-blended cement
proves to be an effective mitigator
of the alkali-silica reaction.
University of Utah research quantified the performance of
pumice-blended cement, including its ability to mitigate ASR.
University of Texas at Austin, on behalf of Texas DOT, used Hess
Standard Pozz in a two-year study to determine viable
commercial SCM alternatives to fly ash in concrete.

8. Graph Data from University of Utah Study
0 20 30 40 50 60
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
LENGTHCHANGE(%)
IMMERSION(Days)
A C C E P T A B L E L I M I T
100%
CEMENT
PUMICE
BLENDED
CEMENT
ASTMC1293(modified)
Concrete MixdesignstestedaccordingtoamodifiedASTMC1293procedureusingType1cementandHighly Reactive coarse
andfineaggregateinanacceleratedASRenvironment(80°Cand1NNaOHsolution)over50days.

9. Graph Data from University of Texas-Austin Study
ThepumiceSCMconcrete mixturekeptexpansionsbelowthe0.04%limitofASTMC1293,validatingtheresults
foundfromASTMC1567AcceleratedMortarBarTestforASR.
ASTMC1293(modifiedmixdesign)

10. Additional Mitigating
Factors
Reduces the pH of the concrete pore solution
by entrapping free alkalis—further squelching ASR.
The pozzolanic reaction tightens the concrete
matrix to block and control moisture
infiltration. What little alkali-silica gel that may
form is denied moisture and cannot swell.

11. Additional Mitigating
Factors
The pozzolanic reaction provides for a denser,
stronger concrete that is more resistant to the
expansive pressure caused by any remaining
ASR gel.
Allows for use of the standard Portland cement
(instead of low-alkali type) and locally-sourced
aggregate, reactive or otherwise.

12. Additional Mitigating
Factors
The consistent chemical makeup and performance
of pumice-blended cement provides a cost
advantage as well as additional benefits to concrete
performance and durability that go beyond simply
mitigating ASR.

13. More Pumice-Blended
Cement Advantages

14. Class 3 Sulfate
Exposure Qualification
More Pumice-Blended Cement Advantages
1 of 2

15. Class 3 Sulfate
Exposure Qualification
More Pumice-Blended Cement Advantages
2 of 2

16. High Resistance to
Chloride Ion Penetration
More Pumice-Blended Cement Advantages

17. Compressive
Strength
2 of 2

18. Compressive Strength
1 of 2

19. Coefficient of Thermal
Expansion
* These experiments were conducted to ensure that the pozzolans
did not have any detrimental effects on the CoTE value of concrete.
*

20. Pumice as an SCM
S U M M A R Y O F
Sulfate StrengthRelative Approx. Workability Minimum
ExposureLevel toOPCControl Price Problemsat Replacement
at28Days perTon HighDosages? forASR(%)
PUMICE Class3 Class3 90% 91% $126 NO 15%
15% 25% 15% 25%(replacement)
AverageASRExpansionat24months
15% 25%(replacement)
0.022±0.007 0.015±0.001

21. Pumice is the
Original Pozzolan
The Romans made impressively
strong and enduring concrete—
stuff with a lifespan of centuries
instead of mere decades, like
our modern concrete. The magic
performance ingredient in
Roman Concrete? Pumice.

22. ASR Miti•GatorTM
The ASR Miti•Gator product is a
pure pumice SCM refined from
the Hess Pumice deposit in southeast
Idaho USA—the purest commercial deposit
of white pumice in the world.
Used as a percentage of cement replacement, it
mitigates ASR and improves concrete performance
overall for an economical pennies-per-yard.

23. TELEPHONE: 1.800.767.4701 x 111
EMAIL: brian@hesspumice.com
WEBSITE: www.asrmitigator.com
DOWNLOAD THE RESEARCH: hesspozz.com/downloads.html