CLINOPTILOLITE A PROMISING POZZOLAN IN CONCRETE

Transcription

1 A NEW LOOK TO AN OLD POZZOLAN CLINOPTILOLITE A PROMISING POZZOLAN IN CONCRETE DIPAYAN JANA Construction Materials Consultants, Inc. & Applied Petrographic Services, Inc. Greensburg, PA USA

2 PRODUCTIVE ZEOLITE DEPOSITS IN THE USA Commercial Applications Clinoptilolite Mordenite Erionite Chabazite Phillipsite Analcime Heulandite Ferrierite Laumontite Common Sedimentary Zeolites Eyde & Holmes 2006 Lacustrine Volcanoclastic Sedimentary Deposits (Tertiary Age)

3 THE BEAR RIVER ZEOLITE, PRESTON, IDAHO - A wholly owned subsidiary of U.S. Antimony Corporation

4 CLINOPTILOLITE [(Na 4 K 4 )(Al 8 Si 40 O 96 ).24H 2 O]

5 CLINOPTILOLITE [(Na 4 K 4 )(Al 8 Si 40 O 96 ).24H 2 O] Na Mg Al Si K

6 BEAR RIVER ZEOLITE 85-90% CLINOPTILOLITE XRD Pattern of BRZ Deposits Mean Particle Size = 12.2 μm Malvern Mastersizer Laser Diffractor

7 ZEOLITE MEETS THE TYPE N SPECIFICATION OF ASTM C 618

8 CONCRETE MIX DESIGN & FRESH CONCRETE PROPERTIES

9 COMPRESSIVE STRENGTH [ASTM C 39] Neither a major strength benefit Nor a major strength loss -Not a major loss, even at 30% zeolite is a gain!

10 RAPID CHLORIDE PERMEABILITY [ASTM C 1202] Now we are talking! A significant reduction In chloride permeability!

11 DRYING SHRINKAGE [ASTM C 311] Drying Shrinkage Test Percent Shrinkage (Microstrain) Days in Air (After 7-day water curing) 0% Zeolite 10% Zeolite 20% Zeolite 30% Zeolite

12 ALKALI SILICA REACTION [ASTM C 311] Reduction in ASR Expansion by Zeolite Replacement (ASTM C 311 Test) Percent Change in Length Days (Above Water) 0% Zeolite 10% Zeolite 30% Zeolite We are talking again Now a Big Time!

13 ACID & SULFATE RESISTANCE A BIG BONUS

14 SULFATE RESISTANCE [ASTM C 1012] 24-hr in mold 48 hrs in lime water at 23C 50g/l Na 2 SO 4 solution mm Mortar Bars

15 POZZOLANIC REACTION - The Secret Behind the Magic of Zeolite in Concrete Calcium Hydroxide Content by Mass (%) CH + A Portion of C-S-H and C-A-S-H Percent Zeolite added with Portland Cement in Neat Pastes w/cm of neat paste = 0.47 XRD TGA DSC Clinoptilolite + Calcium Hydroxide Calcium Silicate Hydrate

16 POZZOLANIC REACTION ANOTHER EXPERIMENT Zeolite Lime Mix = Ancient Mortar Recipe

17 ZEOLITE-BLENDED PASTE PORTLAND CEMENT PASTE SE Image BSE Image ZEOLITE BLENDED PASTE Densification of paste by pozzolanic reaction SE Image BSE Image

18 ZEOLITE-BLENDED PASTE ZEOLITE BLENDED PASTE Ca/Si < 1 PORTLAND CEMENT PASTE Ca/Si > 1

19 CONCLUSIONS Zeolite meets the ASTM C 618 specification for a Type N Pozzolan A reduction in Workability Need for a High-range water-reducer Strength A modest improvement at 10% & reduction at 56d Overall not a significant improvement or impairment in strength Durability Significant improvements in resistance to: - Chloride Permeability - ASR Expansion - Acid/Sulfate Attacks Densification of the microstructure by pozzolanic reaction Zeolite Deposits in the Western USA A Possible Gold Mine for the Construction Industry

20 ACKNOWLEDGMENTS John Lawrence and Steve Olsen at Bear River Zeolite Company (Funding for this project was provided by the BRZ Company) Ted H. Eyde George Desborough, USGS Two nationally & internationally recognized experts who have written numerous articles on zeolites