Publication Date
8-2023
Date of Final Oral Examination (Defense)
5-26-2023
Type of Culminating Activity
Thesis
Degree Title
Master of Science in Civil Engineering
Department
Civil Engineering
Major Advisor
Bhaskar Chittoori, Ph.D., P.E.
Advisor
Nick Hudyma, Ph.D., PE
Advisor
Michael J. Dickey, P.E.
Abstract
Crushed stone and gravel have long been favored for their stability and interlocking properties in Geocell reinforced base course layers of flexible pavement structures. However, their drawbacks, such as depleting reserves, escalating permit costs, environmental compliance, and extensive quarrying impacts, have led researchers to seek alternative options like recycled and on-site materials. Within this framework, utilizing native soil emerges as a promising solution to tackle these challenges. Nevertheless, the grading specifications impose limitations on the fines content allowed in base courses, as determined by the No. 200 sieve. However, the grading specifications pose restrictions on the permissible fines content in Geocell reinforced base courses, as defined by the No. 200 sieve. Extensive research has consistently demonstrated that exceeding the established fines content limit significantly undermines the performance of the soil, particularly in terms of its strength characteristics. This poses a significant challenge when it comes to incorporating native soil into base courses.
The primary objective of this study was to enhance the performance of geocell-reinforced pavement bases utilizing soils with high fines content as a substitute for traditional crushed stone and gravel. The focus was on evaluating the effectiveness of combining Geocells and Microbial Induced Calcite Precipitation (MICP) treatments to achieve this objective. The soil characteristics were evaluated through three laboratory tests: the California Bearing Ratio test, the Calcium Carbonate Content test, and the Free Swell Index test. Although the results indicate a decline in performance as fines content increases, this approach widens the possibilities of allowing relatively higher fines content compared to current specifications. In the present investigation, it was observed that despite the potential weakening of calcite bonds during sample preparation or handling, a discernible enhancement in mechanical performance was still evident. This finding suggests that if measures were implemented to preserve the integrity of these calcite bonds, it is anticipated that the mechanical performance would exhibit even greater improvements compared to the values attained in this study.
DOI
https://doi.org/10.18122/td.2125.boisestate
Recommended Citation
Pisati, Ajay Kumar Reddy, "Maximizing the Performance of Geocell Reinforced Pavement Bases with High-Fines Content Soils Through MICP Treatments" (2023). Boise State University Theses and Dissertations. 2125.
https://doi.org/10.18122/td.2125.boisestate