The attached report covers the work which has been in progress since 1955 to determine whether Minnesota concrete aggregates
have a detrimental reaction with the alkalis present in Portland Cement. It has been found by extensive research elsewhere that, when such reaction does occur, it may produce volume changes of the concrete thus causing internal stresses and consequent disruption of the concrete
This study was prompted by the occurrence of extensive "D" cracking and subsequent serious spalling at many of the joints in the 1941 experimental concrete paving project between Worthington and Brewster. It was suspected that the deterioration of the concrete might have been caused lay alkali-aggregate reactivity,
The results of this study indicate that alkali-aggregate reactivity was not a contributing factor on the experimental project and probably will not occur with any Minnesota concrete aggregates.
