sezer, alper ege university - faculty of engineering - civil engineering department, İzmir, Turkey , tanrinian, nazar ege university - faculty of engineering - civil engineering department, İzmir, Turkey , adamcil, yunus emre ege university - faculty of engineering - civil engineering department, İzmir, Turkey

MECHANICAL BEHAVIOR OF FLY ASH OR CEMENT STABILIZED SAND-BENTONITE MIXTURES EXPOSED TO FREEZE-THAW ACTION

34464

In construction of landfills, embankments and transportation structures, use of clay-sand mixtures are commonly preferred. To provide stability and enhance engineering properties, stabilization with chemical admixtures is a reasonable approach. Unfortunately, freeze-thaw effect is a significant problem controlling the mechanical behavior of soils in cold regions. Since past studies on strength behavior of clay-sand mixtures stabilized using fly ash or cement exposed to freeze-thaw action is limited, in this study, an experimental framework was used to investigate the effects of clay content, admixture type, number of freeze-thaw cycles on strength of clay-sand mixtures including pozzolanic cement or class C fly ash. Sand specimens including 4, 8, 12 and 16% bentonite by weight were stabilized with 3, 6, 9 % pozzolanic cement and 5, 10, 15 and 20 % class C fly ash by weight, specimens were prepared at optimum water content of mixtures. The specimens were then subjected to 1, 3 and 10 freeze-thaw cycles after 28 days of curing period. Freeze-thaw resistance of specimens was determined by carrying out unconfined compression tests. Experimental results revealed that, under certain curing conditions, cement and fly ash stabilization positively affects the strength of sand-bentonite mixtures and dominates the negative effects of freeze-thaw action. As expected, specimens stabilized with pozzolanic cement provided higher freeze-thaw resistance compared to those amended with fly ash. Besides, analysis of secant modulus values revealed that, cement stabilized specimens showed a more rigid behavior after freeze-thaw action.

1008

Sand , bentonite mixtures , Freeze , thaw effect , Cement , Fly ash , Stabilization

Anadolu University Journal of Science and Technology. A : Applied Sciences and Engineering

1017