ISSN: 0090-3973
Published Online: 21 December 2005
Page Count: 9

Durability Effects on Flexural Behavior of Fly Ash Stabilized Limestone Aggregate

Khoury, N
Doctoral Candidate,School of Civil Engineering and Environmental Science, University of OklahomaCarson Engineering Center,OK,

Zaman, M
David Ross Boyd Professor and Aaron Alexander Professor,Associate Dean for Research, College of Engineering, University of OklahomaCarson Engineering Center,OK,

(Received 3 September 2005; accepted 6 October 2005)

Abstract

This paper examines the flexural behavior of beams, representing a cementitiously stabilized aggregate base, under cyclic loading. Specifically, the effects of different freeze-thaw (F-T) procedures and number of F-T cycles on flexural response are studied. Aggregate beams stabilized with 10 % class C fly ash, cured for different periods (1 h, 3 days, and 28 days) and subjected to F-T cycles are tested for resilient modulus in flexure (M^rf) and modulus of rupture (MOR). The M^rf values decreased with increasing F-T cycles. Changes in M^rf are sensitive to curing periods. Reduction in M^rf and MOR 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. A correlation between M^rf and stress ratio shows that M^rf decreases with increasing stress ratio, in an overall sense. A steep decrease in M^rf is observed for stress ratios in the range of 0.1 to 0.3, beyond which no significant reduction is evident.

Keywords:
durability, freeze-thaw cycles, resilient modulus, aggregate bases, modulus of rupture

Paper ID: JTE14085
DOI: 10.1520/JTE14085
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