Abstract:
LABORATORY STUDIES OF AGGREGATES AND CONCRETE WERE INITIATED AFTER FIELD-PERFORMANCE SURVEYS INDICATED SIGNIFICANT CONCRETE DETERIORATION IN CERTAIN AREAS OF WYOMING. THESE LABORATORY STUDIES WERE TO DETERMINE CAUSES FOR THE DETERIORATION THROUGH ANALYSIS OF THE AGGREGATES AND SIMULATED-WEATHERING TESTS ON CONCRETE MADE WITH THESE MATERIALS AND TO DEVELOP PREVENTIVE MEASURES AGAINST FUTURE DETERIORATION. THE TESTS INDICATED THREE OF THE AGGREGATES WERE POTENTIALLY REACTIVE WITH CEMENT ALKALIES; USE OF CEMENT WITH LOW ALKALI CONTENT OR OF POZZOLANIC ADMIXTURES IS INDICATED. ONE AGGREGATE ALSO CAUSED RAPID CONCRETE DETERIORATION UNDER FREEZING-AND-THAWING ACTION, WETTING AND DRYING, OR RAPID TEMPERATURE CHANGE. RESISTANCE TO THESE EFFECTS WAS ALSO IMPROVED BY POZZOLANIC ADMIXTURES. TWO OTHER AGGREGATES, NOT ALKALI REACTIVE, WERE ALSO AFFECTED BY RAPID TEMPERATURE-CHANGE TESTS. FURTHER STUDY OF THE EFFECT OF RATE OF TEMPERATURE CHANGE ON CONCRETE DETERIORATION INDICATED THAT TOO RAPID A CHANGE IN LABORATORY TESTS MAY INTRODUCE FACTORS NOT PRESENT IN NATURAL WEATHERING CONDITIONS. SOME EXPLORATORY DATA ON POSSIBLE CHEMICAL FACTORS ENTERING INTO TEMPERATURE-CHANGE TESTS ARE ALSO PRESENTED. /AUTHOR/
Supplemental Notes:
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