California Experience With the Expansion of Concrete Through Reaction Between Cement and Aggregate
Thomas E. Stanton, O. J. Porter, L. C. Meder, and Allen Nicol
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This group of papers brings up to date the work done by the Materials and Research Department of the California Division of Highways during the last 3 years in the investigation of the cause of the serious deterioration of concrete in certain areas of the State. Many data are presented supporting the contention that the cause of the trouble is a chemical reaction between alkali in the cement and some mineral in the aggregate. Long-time (up to 3 year) test results are included and methods and results of various acceler-ated test procedures are described. Studies on the subject of permissible alkali content, effect of pozzolanic admixtures, the nature of the reactive aggregates, possible correctives and the need for a comparative petrographic study of various known and unknown reactive aggregates are discussed at length. Interesting data are presented showing the extent to which a highly reactive mineral is apparently innocuous when present in excess quantities which maybe as low as only IO or I5 percent of the aggregate particles. Eight lines of investigation are suggested for future research.