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

Yıl 2017, Cilt: 18 Sayı: 5, 1008 - 1017, 31.12.2017

Alper Sezer Nazar Tanrınıan Yunus Emre Adamcıl

https://doi.org/10.18038/aubtda.332155

Öz

In construction of landfills,
embankments and transportation structures, use of clay-sand mixtures are
commonly preferred. To provide stability and enhanced engineering properties,
stabilization with chemical admixtures is a reasonable approach. Unfortunately,
freeze-thaw effect is a significant problem affecting soil behavior in cold
regions. Studies on strength behavior of clay-sand mixtures stabilized using
fly ash or cement exposed to freezing-thaw action is limited, and need further
investigation. For this reason, in this study, using pozzolanic cement or class
C fly ash as admixtures for clay-sand mixtures, an experimental framework was
used to investigate the effects of clay content, admixture type, number of
freeze-thaw cycles on strength of these mixtures. Sand specimens including 4,
8, 12 and 16% bentonite by weight were stabilized wih 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 freezing / thaw cycles after 28 days of curing period.
Freeze-thaw resistance of specimens was determined by application of unconfined
compression tests. Experimental results revealed that, under the curing
conditions adopted, cement and fly ash stabilization positively affects the
strength of sand-bentonite mixtures and dominates the negative effects of
freeze-thaw action. Pozzolanic cement stabilized samples 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. 

Anahtar Kelimeler

Sand-bentonite mixtures, freeze-thaw effect, cement, fly ash

Kaynakça

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