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Recent Advances and Field Applications Using Alternative Cementitious BindersUsing Alternative Cementitious BindersBrian H. Green, Robert D. Moser, Christopher M. MooreU. S. Army Engineer Research and Development Centery g p
Jon Belkowitz, Intelligent Concrete
Unconventional ConcreteUnconventional ConcreteAnna Maria Workshop XIIINovember 7-9, 2012Holmes Beach, Florida
US Army Corps of EngineersBUILDING STRONG®
Outline• Problems from Dust Production• Dust, Corrosion, and Soil StabilizationDust, Corrosion, and Soil Stabilization• Location of Test Area • Local MaterialsLocal Materials• Chemically-Bound Soil Technologies
for Soil Stabilizationfor Soil Stabilization• Test Road Sections• What’s Going OnWhat s Going On…• Summary and Questions
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Dust Production in Army Training Areas• Unsurfaced roads and
landing zones are major problems in arid terrainproblems in arid terrain
• Dust introduces abrasives into the vehicle systems yand clogs air filters
• Dust control agents are frequently inorganic saltsfrequently inorganic salts (chloride-containing) that can produce additional corrosion problems
• Conventional paving is not practical in many locations
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practical in many locations
Pohakuloa Training Area (PTA) Test Site• Serious dust problem at site• Abrasive, corrosive dust• Moderate traffic• Soil is largely volcanic glass
that is reactive in an alkalithat is reactive in an alkali-activated geopolymer
• Cementation should be more durable than dust palliatives
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Soils at PTA Test Site• Alumino/siliceous aggregates
with limited crystallinity• Amenable to formation of• Amenable to formation of
chemically-bound geopolymer• Sharp edges, and cornersp g• Wide range of particle sizes
SEM Micrograph of Soil [CAW3294.MDI] Hawaian Soil BAAF05 Malone[CAW3295.MDI] Hawaian Soil BAAF04 Malone[CAW3294.MDI] Hawaian Soil BAAF05 Malone[CAW3295.MDI] Hawaian Soil BAAF04 MaloneSEM Micrograph of Soil
d=3.
21781000
1500
ount
s)
00-018-1202> Anorthite - (Ca,Na)(Si,Al)4O8
d=3.
21781000
1500
ount
s)
00-018-1202> Anorthite - (Ca,Na)(Si,Al)4O8
Only crystalline phase present
feldspar AnorthiteNa0 05Ca0 95Al1 95Si2 05O8
d=3.
1886
d=2.
5252
d=3.
7638
d=4.
052
d=2.
9533
d=1.
7756
d=2.
7072
d=1.
4892
d=2.
1446
d=3.
1442
d=2.
8449
d=1.
8351
d=1.
6978
d=1.
4560
d=3.
3758
d=2.
5644
d=2.
4834
d=1.
8793
d=1.
6269
d=2.
2101
d=1.
9918
d=2.
2895
=1.9
308
=6.4
94
500
Inte
nsity
(Co
d=3.
1886
d=2.
5252
d=3.
7638
d=4.
052
d=2.
9533
d=1.
7756
d=2.
7072
d=1.
4892
d=2.
1446
d=3.
1442
d=2.
8449
d=1.
8351
d=1.
6978
d=1.
4560
d=3.
3758
d=2.
5644
d=2.
4834
d=1.
8793
d=1.
6269
d=2.
2101
d=1.
9918
d=2.
2895
=1.9
308
=6.4
94
500
Inte
nsity
(Co 0.05 0.95 1.95 2.05 8
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d dd dd=
10 20 30 40 50 60Two-Theta (deg)
0
d dd dd=
10 20 30 40 50 60Two-Theta (deg)
0
Alkali-Activated Geopolymer: An Alternative• Alkali-activated geopolymers are special cements formed
by mixing a concentrated alkaline solution with a finely-divided reactive aluminosilicate (sometimes with Ca too)divided reactive aluminosilicate (sometimes with Ca too)
• Alkali-activated geopolymericcements are strong, fast-setting, inexpensive, and very versatile
• Manufactured from glassy silicates like slag fly ashsilicates like slag, fly ash, metakaolin, and volcanic ash
• Can use waste alkalis from manufacturing operations
• No portland cement is involved!
Soil solidified with alkali-activated mixture using slag
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Why Use an Alkali-Activated Alternative?• Fast: mixture sets in hours and
gets ultimate strength in daysE t Obt i M t i l it bl• Easy to Obtain Materials: suitable raw materials are available almost everywhere (eg, fly ash, slag)
• Economical: uses waste/local materials or low-fired clay soilsV til b i h i t d t
Geopolymer
• Versatile: basic chemistry adapts from a wide variety of glassy aluminosilicates
• Variation of natural weathering process that occurs in volcanic ash deposits Skvara et al, 2006
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ash deposits ,
Previous Usage Worldwide• Widely used in Australia• Marketed by Blue Circle
C t C dCement Company and Boral Cement
• Used in over 100 projectsUsed in over 100 projects of 10,000 to 150,000 m2
(2.5 to 37 acres)R t d t N i h• Reported to use Na-rich kiln dust, slag, and activator such as lime
• Broad range of compositions
Boral Roadment® application
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Current Geopolymer Formulation• Alkali Rich Glassy Aluminosilicate Aggregates
• From local PTA volcanic soil• Slag (ASTM C989) – Approx 6 wt%
• Source: foundry located in Southern California• Fly Ash (Direct from Coal Plant) – Approx 6 wt%
• Plant located on the island of Oahu• Chemical composition close to Class F (not F or C)
• Hydrate Lime (ASTM C977) – Approx 6 wt%y ( )• Sodium Carbonate (Soda Ash) – Approx 6wt%• Water: w/cm of approx 0.17
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pp
Geopolymerization Reactions
• Initial: Na2CO3 + Ca(OH)2Fi l N OH d C COExchange Reaction • Final: NaOH and CaCO3
Exchange Reaction
• NaOH breaks down reactive surface of aggregatesF A S H l h
GeopolymerizationRxn: Aggregates
• Forms A-S-H gel phasegg g
G l i i • Alkalis down fly ash and slag• For C-A-S-H gel phase
GeopolymerizationRxn: Supplementary Cementing Materials
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Batch Mixing in Laboratory
Blend Until B lli O
Add Activator Solution
Balling Occurs
Blend Dry Components
Mixture Components
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Consolidation Methods• Best performance observed when mixture is roller-
compacted to consolidate
• Roller Compacted Method Pros:
• Roller Compacted Method Cons:
• Decreased Manpower• Faster Placement
Ti
• Does Not Produce the Highest Quality SurfaceD i D dTimes
• Method Similar to Soil Compaction
• Density Depends on Compacted Effort
• Somewhat RequiresCompaction• Does Not Require
Specialized Skill Set
Somewhat Requires Continuous Placement
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Trial Batching at Univ. of Hawaii and ERDC
• University of Hawaii test ti
• Trial batching at ERDC C t & M t i l B hsections: Concrete & Materials Branch:
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Resulting Microstructure• Alkali attacks edges and
corners of coarse Initial
volcanic aggregates • Fines can react
completely• C-A-S gel phase acts as
binder similar to C-S-H in Portland cement systemsS d i l
Final
• Secondary minerals (zeolites) also contribute to cementation
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to cementation
Resulting Microstructure• Hardened chemically-bound soil microstructure
similar to hardened Portland cement concrete
Current Mixture:• ~6.4 MPa (927 psi) ( p )
at 7 days• ~12.4 MPa (1800 psi)
at 28 daysy• Highest compressive
strengths when >135 pcf unit weight
Polished Cross Section of Hardened
p gachieved during field compaction
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Chemically-Bound Soil
From the Lab to the Field…• Placement of chemically-bound soil mixture in the
field using roller-compacted method:g
Stats on PTA trial placement:trial placement:• Two 12ft lanes • 6in compacted• 6in compacted• 8-10in placed• 0 5mi in length
Cross section of roller-compacted placement of chemically bound soil
0.5mi in length
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placement of chemically bound soil
What’s Happened!• Placement at the PTA test site• Photos from the field provided by Chris MoorePhotos from the field provided by Chris Moore
and Samuel Craig (US Army ERDC – CMB)
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What’s Happened…• Placement at the PTA
test site• Issues with high winds• Iterative process to
optimize placementoptimize placementOn-site equip. for placement
On-site batch plantSpreading for roller-compaction
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p
Summary and Conclusions• Control of abrasive dust is a serious corrosion
and equipment maintenance issue• Alkali-activated geopolymerization is being
investigated using glassy volcanic soils• Reports in the literature support feasibility along
with experience from Australian manufacturers• ERDC has developed initial mixture designs and
procedures for field placement• Successful placement of test section at PTA site
using chemically-bound soil stabilization t h l
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technology
Future Directions• Temporary storage pads for government facilities p y g p g
• Upcoming project in Charleston, SC to construct parking slabs for storage of MRAPs returning to USW ki ith I t lli t C t t d lt ti• Working with Intelligent Concrete to produce alternative cementitious material mixture proportions using the “less reactive soil” from local SC area
• Include the use of nanoparticles to activate the system
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Acknowledgements• The authors wish to recognize the participants at ERDC that
worked on this project:Philip G. Malone, David M. Bailey, Peter G. Bly, and Sean W. Morefield
Melvin C. SykesP l G Alli
Samuel L. Craig Charles A. Weiss, Jr.
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Paul G. Allison
Acknowledgements• The authors wish to recognize the Sponsors of the DoD
Corrosion Prevention and Control Program:• Office of Under Secretary of Defense, Office of Corrosion Policy
and Oversight (Director, Mr. Dan Dunmire). • Deputy Assistant Secretary of the Army Acquisition Policy and
Logistics (Army Corrosion Control Prevention Executive, Mr. Wimpy D. Pybus).
• Assistant Chief of Staff for Installation Management (Mr. David Purcell).
• Headquarters, U.S. Army Installation Management Command (Mr. Paul Volkman).
• Technical content previously approved for release by Director, Geotechnical and Structures Laboratory, US Army ERDC
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Thank You!
Please contact for more info or copy of presentation: p
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