Flexural Properties of Stabilized Aggregate Beams Subjected to Freeze-Thaw Cycles (05-2046)
Naji Khoury, Notre Dame University, Lebanon
Musharraf Zaman, Oklahoma University, Norman

This paper examines the flexural behavior of stabilized beams, representing a stabilized aggregate base, under cyclic loading. Specifically, effect of different freeze-thaw (F-T) procedures and number of F-T cycles on flexural response is studied. Aggregate beams stabilized with 10% class C fly ash and subjected to different curing periods (1 hr, 3 days, and 28 days) and F-T cycles are tested for resilient modulus in flexure (Mrf) and flexural strength (FS). The Mrf values decreased as F-T cycles increased up to 16 cycles. Changes in Mrf are sensitive to curing period. Reduction in Mrf and FS and degradation in specimens are attributed to the increase in moisture content during the thawing phase and formation of ice lenses during the freezing phase. Degradation occurs when the expansion of ice lenses exceeds the pore space available. It is observed that different laboratory procedures produce different effects. A correlation between Mrf and stress ratio shows that Mrf decreases with increasing stress ratio, overall. A steep decrease in Mrf is observed for stress ratios in the range of 0.1 to 0.4, beyond which no significant reduction is evident. These results demonstrate a need for addressing the flexural properties and durability adequately when designing a stabilized aggregate base.