Abstract
The effect of aging treatment on lime-falling of steel slag was studied by examining the microstructure and measuring the expansion in CBR mold soaked in water. The stability of crushed stone was decreased with the addition of small amounts of industrial fresh slag. After the slag was remolten in order to assimilate the calcined lime stone completely, the expansion coefficient of the slag didn't exceed 0.2%, even in the case of 5.3% of free lime content. Then, the new method was applied for the evaluation of the free lime in aged slag. The analytical values corrected as water-reactive form were below about 2% in the six-month aged slags. Those slags scarcely included unassimilated lime and indicated high stability in the CBR test. It was found that the free lime of unassimilated form changeed into stable compounds by the aging treatment. Most of the remaining lime was of the crystallized phase from molten slag and didn't bring the lime-falling to the aged slag.
