| Abstrakt: |
The current study analyzed a total of 28 flexible pavement sections for evaluating influence of cementitious stabilization of soil on pavement distresses under different climate, traffic, and reliability level conditions. A total of three stabilizers, namely, 3% lime, 15% class C fly ash (CFA) and 15% cement kiln dust (CKD) were selected. A total of six types of pavement distresses namely, total rutting, asphalt concrete (AC) rutting, AC bottom-up cracking, AC top-down cracking, AC thermal cracking and international roughness index (IRI) values were predicted for a period of 20 years (240 months) using AASHTOWare pavement mechanistic-empirical (ME) design software. It was found that cementitious stabilization is effective in reducing only total rutting, bottom-up cracking and IRI under different climate, traffic, and reliability levels. The amount of improvement was found dependent on resilient modulus values of stabilized soil layer. However, no effect of cementitious stabilization of subgrade soil was noticed on top-down cracking and thermal cracking of AC layer. On the contrary, cementitious stabilization increased AC rutting of pavement. The maximum percent increase in AC rutting was found 6.4% for CKD stabilization in WY climate, 5.5% for CKD stabilization under 1000 and 5000 traffic levels, and 5.6% for CKD stabilization at a reliability level of 80%. Among all six distresses, stabilization was found most effective in reducing bottom-up cracking (or fatigue cracking) of AC layer under different climate, traffic, and reliability level conditions. Further, the level of improvement in bottom-up cracking due to stabilization was found most effective under warmer climate region and highest reliability level. Specifically, the maximum percent improvement in bottom-up cracking was noticed 61.3% for CKD stabilization in TX climate, 70.5% for CKD stabilization under 10,000 traffic level, and 92.9% at a reliability level of 95%. The cementitious stabilization of subgrade soil showed highest percent improvement in reducing IRI values under coldest temperatures (1.8% for CKD stabilization in WY climate), highest traffic level (1.8% for CKD stabilization under 10,000 traffic level), and lowest reliability levels (1.1–1.5% at a reliability level of 80%). |
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