REACTION OF AGGREGATE WITH LOW-ALKALI CEMENT

AN EXPANSION OF 1.0% AT AN AGE OF ONE YEAR OR LESS IS EXCESSIVE. THE QUANTITY OF ALKALI-REACTIVE MATERIAL IN SAND NEEDED TO OBTAIN A MAXIMUM REACTION IS DEPENDENT ON THE AMOUNT OF ALKALI IN THE CEMENT. IF AN AGGREGATE HAS A RELATIVELY LARGE AMOUNT OF ALKALI REACTIVE MATERIAL, A LOW ALKALI CEMENT WILL CAUSE LITTLE, IF ANY, REACTION WHEREAS THE SAME CEMENT WHEN USED WITH A SAND HAVING ONLY A SMALL AMOUNT OF REACTIVE MATERIAL MAY CAUSE AN OBJECTIONABLE EXPANSION. IT IS BEST TO TEST CEMENT AND AGGREGATE, IN PROPORTION AS SPECIFIED FOR WORK, TO DETERMINE IF AN ALKALI AGGREGATE REACTION WILL TAKE PLACE. /AUTHOR/