Matching Items (143)
Description
Concern and interest about the environment and ecologic systems have promoted the usage of earth as a construction material. Technology advancement has resulted in the evolution of adobe into compressed stabilized earth blocks (CSEB). CSEB’s are prepared by compressing the soil-stabilizer mixture at a particular stress. In order to accomplish the required strength, cement has been used in a regular basis as stabilizing agent. It is of interest to find means to reduce the cement used in their construction without affecting its dry strength and durability. In this study, natural fibers were used along with lower proportions of cement to stabilize soil with varying fine content. Blocks were compacted at 10MPa stress and prepared by using 7%, 5% and 3% cement along with fiber content ranging from 0.25% to 2%. The effect of fine content, cement and fibers on strength and durability of the CSEB blocks were studied. Different sand/fine fractions of a native Arizona soil were used to fabricate the blocks. Results indicate that the compressive strength reaches a maximum value for blocks with 30% fine content and inclusion of fibers up to 0.5% increased the dry compressive strength. The use of 0.25% fiber by weight and 5% cement content showed comparable dry compressive strength to that of the 7% cement blocks with no fibers. The dry strength of the blocks reached an optimal condition when the combination of materials was 30% fines, 5% cement and 0.5% fibers, which satisfied the strength requirement given by the ASTM C62 and ASTM C216 standards for construction material. The CSEB’s with 0.5% fiber had higher toughness. The durability was determined by subjecting the CSEBs to wetting and drying cycles. The blocks with 5% cement withstand the durability test as the dry strength was higher than that required for construction use.
The blocks were also submitted to heating and cooling cycles. After 12 cycles, the specimens showed a reduction in strength, which further increased as the number of cycles increased. Finally, the thermal resistivity of fiber reinforced CSEB was found to be higher than that for clay bricks.
The blocks were also submitted to heating and cooling cycles. After 12 cycles, the specimens showed a reduction in strength, which further increased as the number of cycles increased. Finally, the thermal resistivity of fiber reinforced CSEB was found to be higher than that for clay bricks.
ContributorsPadmini Chikke Gowda, Rakshith (Author) / Zapata, Claudia (Thesis advisor) / Kavazanjian, Edward (Committee member) / Jang, Jaewon (Committee member) / Arizona State University (Publisher)
Created2016
Description
The researchers build a drone with a grasping mechanism to wrap around branches to perch. The design process and methodology are discussed along with the software and hardware configuration. The researchers explain the influences on the design and the possibilities for what it could inspire.
ContributorsGoldenberg, Edward Bradley (Co-author) / Macias, Jose Carlos (Co-author) / Downey, Matthew (Co-author) / Zhang, Wenlong (Thesis director) / Aukes, Daniel M. (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Understanding the shear strength of soil at different levels of saturation is necessary for various
engineering applications, especially in geotechnical and civil engineering projects. The objective
of this thesis is to conduct an extensive literature review of the use of geosynthetics to improve the
strength of soil material, conduct laboratory testing components to assess the shear strength of soil
at different water contents, and participate in the Leadership through Mentoring program to gain
mentoring and leadership skills. The laboratory component focuses on analyzing the shear strength
of soil samples with different water contents, specifically at 6%, 10%, 12.3%, 15%, 17%, and 19%.
The soil-water mixtures were prepared with precision to achieve these specific water contents.
Static compaction techniques were then employed to mold the soil samples to desired densities.
The experimental setup involved subjecting the molded soil samples to a direct shear test using a
direct shear machine. This apparatus allowed for the measurement of normal and shear stress, as
well as shear and normal displacements during the testing process. These data were used to
determine the cohesion and internal friction characteristics of the soil samples at different degrees
of saturation.
The results obtained from the direct shear tests revealed valuable insights into the shear strength
behavior of the soil under varying saturation levels. The cohesion and internal friction parameters
were found to exhibit distinct trends as the water content in the soil changed. The cohesion and
internal friction parameters were found to exhibit distinct trends as the water content in the soil
changed. The friction angle did not change significantly at different water contents, while the
cohesion intercept trend appears to be contradicted the results reported in the literature, as there is
a slight increase. The unexpected results might be due to the testing device failing after the third
moisture content test. A different approach could have been taken to compact the specimens at
optimum moisture content to get the same soil structure for each moisture content. These findings
need to be re-evaluated based on the conclusion outlined in this report. Further research in this
area could lead to enhanced models and methodologies for predicting soil behavior in real-world
scenarios.
In addition to the experimental tasks performed, I participated in a program to gain leadership
skills through a mentoring format. The goal of the program was to help me understand my strengths
and weaknesses to become a better leader. Through interactive assessments, feedback mechanisms,
3
and learning resources, I was able to understand what I was good and bad at. The weekly
assessments helped me to constantly be honest with myself and evaluate myself as a student, peer,
and leader. The program gave me a graduate student mentor that guided me through the process of
learning how to manage projects effectively and understanding how to lead. Through the lessons
learned and challenges encountered, I was able to grow and become a more efficient listener as
well as analyze information better. These tools helped me to enhance my leadership skills and
become a more effective and impactful leader.
ContributorsMontano, Samuel (Author) / Zapata, Claudia (Thesis director) / Kavazanjian, Edward (Committee member) / Barrett, The Honors College (Contributor) / Civil, Environmental and Sustainable Eng Program (Contributor) / Construction Engineering (Contributor)
Created2024-05