CHARACTERISTICS OF KINGSTON CARBONATE ROCK REACTION
THE POINTS OF SIMILARITY BETWEEN THE ALKALI-REACTIVITY OF THE KINGSTON CARBONATE ROCK AND THE ALKALI-SILICA TYPES OF REACTION ARE: (1) THE SPECIFIC INFLUENCE OF ALKALI CONTENT, WHETHER IT DERIVES FROM THE CEMENT OR IS ADDED, (2) THE MORE AGGRESSIVE INFLUENCE OF THE SODIUM THAN THE POTASSIUM HYDROXIDE, (3) THE INFLUENCE OF THE TEMPERATURE, WITH EVIDENCE OF AN OPTIMUM, (4) THE DIRECT INFLUENCE OF MOISTURE, AND (5) THE ABNORMAL EXPANSION OF CONCRETE, FOLLOWED BY MAP-CRACKING WHERE MOISTURE CONDITIONS VARY AT TWO SURFACES. CHARACTERISTICS THAT SHOW SOME LIMITED DEGREE OF SIMILARITY ARE: (1) RATE AND DEGREE OF EXPANSION, (2) DECREASE IN EXPANSION WITH DECREASE IN PARTICLE SIZE OF AGGREGATE, APPARENTLY DUE TO BREAK-UP AT PLANES OF WEAKNESS AS WELL AS TO INCREASE IN SURFACE AREA FOR A FIXED AMOUNT OF ALKALI, (3) RIM FORMATION PRESENT BUT DIFFERENT IN APPEARANCE FROM THE ALKALI-SILICA TYPE, AND (4) MICROSCOPIC EVIDENCE OF FRACTURING OF PASTE AND AGGREGATE BUT DIFFERENCE IN APPEARANCE OF AFFECTED AREAS. DISTINGUISHING FEATURES ARE: (1) ABSENCE OF SIGNIFICANT QUANTITIES OF GEL, BUT PORE VOLUME WAS EXTREMELY SMALL, AND AMOUNT OF SILICA VERY SMALL, HENCE IT IS NOT LIKELY THAT FAILURE TO DETECT GEL DUE TO ITS DISTRIBUTION THROUGHOUT THE PORES, (2) ABSENCE OF MINERALS OR ROCK TYPES KNOWN TO REACT DELETERIOUSLY WITH CEMENT ALKALI, (3) FAILURE OF ALKALI-SILICA REACTION INHIBITORS TO CONTROL THIS ALKALI-CARBONATE REACTION, (4) INCREASE IN WATER-CEMENT RATIO APPARENTLY DOES NOT INCREASE RATE OF REACTION, AND (5) UNCRACKED PARTS OF THE AFFECTED CONCRETE APPEAR TO REMAIN INTACT, EVEN AFTER MANY YEARS. THE KINGSTON CARBONATE REACTION IS NOT DETECTABLE BY THE STANDARD ASTM TESTS. IT MAY BE DETECTED BY EXPOSING CONCRETE PRISMS MADE MADE WITH THE SUSPECTED ROCK AND A HIGH ALKALI CEMENT TO NEAR 100 PERCENT RELATIVE HUMIDITY AND 73 F CONDITIONS, OR TO THE SCHOLER TEST. IT MAY ALSO BE DETECTED BY MEASURING EXPANSIONS OF THE ROCK IN ALKALINE SOLUTION. AS A TENTATIVE CONCLUSION ROCKS COMPOSED OF NEAR EQUAL PROPORTIONS BY WEIGHT OF DOLOMITE AND CALCITE MAY BE REGARDED AS SUSPECT AND IT SEEMS POSSIBLE THAT A CONNECTION EXISTS BETWEEN THE EXPANSIVE REACTIVITY AND THE DEDOLOMITIZATION REACTION (REPLACEMENT OF DOLOMITE BY CALCITE AND BRUCITE). /AUTHOR/
- Record URL:
-
Supplemental Notes:
- No 275, pp 18-31, 10 FIG, 3 TAB, 12 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
-
Authors:
- Swenson, E G
- Gillott, J E
-
Conference:
- 39th Annual Meeting of the Highway Research Board
- Location: Washington DC, United States
- Date: 1960-1-11 to 1960-1-15
- Publication Date: 1960
Media Info
- Monograph Title: Concrete quality control, aggregate characteristics and the cement-aggregate reaction
-
Serial:
- Highway Research Board Bulletin
- Issue Number: 275
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Alkali aggregate reactions; Block cracking; Carbonate rocks; Detection and identification; Detectors; Dolomite; Expansion; Fracture mechanics; Humidity; Hydroxides; Measurement; Moisture content; Pastes; Pore space; Potassium; Silica; Sodium; Temperature; Water cement ratio
- Uncontrolled Terms: Characteristics
- Old TRIS Terms: Calites
- Subject Areas: Geotechnology; Highways;
Filing Info
- Accession Number: 00217745
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Aug 12 1994 12:00AM