Engineering Commons^™

Machine Learning Methods To Map Stabilizer Effectiveness Based On Common Soil Properties, Amit Gajurel

Boise State University Theses and Dissertations

Unconfined compressive strength (UCS) has been widely used as one of the primary criteria for the selection of optimum type and amount of chemical stabilizer for subgrade/base stabilization. Guidelines established by various state and federal agencies aid in selecting these optimum values by recommending an initial type and amount based on a wide range of soil index properties. A significant number of laboratory trials have to be done to establish the optimum type and amount of stabilizer for a given target strength. This process takes a copious amount of time, money, and the workforce. In addition to that, the finite …

Effect Of Particle Breakage On Ballast Permanent Deformation — A Study Using The Discrete Element Method, Beema Dahal

Boise State University Theses and Dissertations

The ballast layer comprises relatively large (often as large as 63 mm) angular particles that mainly function to dissipate train-induced stresses from crossties to the underlying subgrade soils and to provide rapid drainage for surface water. Moreover, the ballast layer is also critical towards ensuring a smooth riding track profile, dampening dynamic loads, as well as providing lateral, longitudinal and vertical resistance against excessive track deformations. Under train loading and during track maintenance processes like tamping, individual ballast particles can undergo significant breakage leading to fouling of the ballast layer. The fouling mechanism leads to gradual deterioration in ballast shear …

Physio-Chemical Degradation Of Concrete: A Ramification Of Coupled Freeze-Thaw And Sulfate Attack, Md Aminul Islam

Boise State University Theses and Dissertations

Concrete structures experience damage due to Sulfate Attack (SA) and Freeze-Thaw (F-T) in cold regions containing ample amount of sulfate species. The combined effect of SA and F-T is a multiscale multiphysics damaging process for cementitious materials involving complicated chemical reactions and phase transition inside concrete pores. This thesis is a compilation of two theoretical models describing the SA induced damage in an unsaturated cementitious medium and damage due to the combined effect of SA and F-T. The classical theory of phase change and a diffusion-reaction process is utilized in the development of the models. The validity of the proposed …

Studying The Use Of Microbial Induced Calcite Precipitation As A Shallow Stabilization Alternative To Treat Expansive Soils, Tasria Rahman

Boise State University Theses and Dissertations

Expansive soils usually recognized as swell-shrink soils have been a problem for civil infrastructure for a long time. It has been a very common practice to use chemical stabilizers including cement and lime to stabilize expansive soils, especially for lightly loaded structures. However, due to the the detrimental effects of these stabilizers on the environment and several occurrences of premature failures after stabilizing with chemical additives, engineers are in search of sustainable stabilization alternatives. Microbial Induced Calcite Precipitation (MICP) is a promising process, which can improve the properties of expansive soil through calcite precipitation. Previous research has shown promise for …

Effect Of Subsurface Conditions On Flexible Pavement Behavior: Non-Destructive Testing And Mechanistic Analysis, Md. Fazle Rabbi

Boise State University Theses and Dissertations

The behavior of flexible pavements under traffic and environmental loading can be significantly affected by subsurface conditions. Inadequate support conditions under the surface can lead to excessive pavement deformations, often leading to structural and functional failure. This research effort focused on assessing the effects of base/subbase and subgrade layer conditions on flexible pavement behavior. The results of this study are presented in the form of two journal manuscripts.

The first manuscript focuses on utilizing pavement structural and functional evaluation data in making pavement rehabilitation decisions. Visual distress surveys and Falling Weight Deflectometer (FWD) testing are often carried out by agencies …

Feasibility Of Aerial Tramway At Boise State University, Majed Alsaqyani

Boise State University Theses and Dissertations

The use of aerial tramways is becoming common in cities as a way to provide reliable, safe, sustainable, and cost-effective mass transportation. The aerial tramway is especially effective in the most congested areas of major cities. The growth of Boise State University (BSU) and downtown Boise makes this location especially attractive for a tramway. Moreover, based on data collected for this analysis, it is clear that the BSU community is open to using the tramway instead of more traditional modes of transportation.

The viability of the tramway is further enhanced because the computer science department has moved to City Center …

Studying The Applicability Of Biostimulated Calcite Precipitation In Stabilizing Expansive Soils, Md Touhidul Islam

Boise State University Theses and Dissertations

Of the four types of soils, clays are often associated with issues related to low bearing capacity, high compressibility, swelling and shrinking nature. For example, expansive soils swell and shrink with moisture ingress and digress and are prevalent in several parts of the world causing billions of dollars in damages annually to various civil infrastructures. Several ground improvement techniques such as chemical stabilization, deep soil mixing, moisture barriers, and others were employed to counteract these soils. However, these methods are impractical in certain situations and unsustainable in others due to their economic and environmental impacts. Microbiological treatment of soils could …