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Experimental Investigation of the Durability of Rammed Earth Materials in Different Environments

Ghasemalizadeh, Saeed | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52655 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Toufigh, Vahab
  7. Abstract:
  8. Rammed earth structures have attracted the attention of engineers and researchers in recent years due to their economic advantages, sustainable development, and environmental sustainability. One of the main concerns for public opinion for acceptance of Rammed Earth as a reliable construction material is their durability. Previous studies have investigated the durability of rammed earth materials by conducting wet and dry cycle test, accelerated erosion test, and rain simulation in the laboratory environment. This research studied the durability of cement stabilized rammed earth (CSRE) for one year under the aggressive environments. Three cement contents were considered for preparing the CSRE specimens. They were exposed to acidic, alkaline, sulfate, and high moisture environments. The mechanical properties of CSRE specimens were determined in intervals of 1, 3, 6, 9 and 12 months of immersion in solutions. Results revealed that the sulfate environment was the most destructive solution for CSRE specimens, which caused complete degradation of low cement specimens and decreased the compressive strength of high cement content CSRE significantly. Scanning electron microscope (SEM) observation proved the formation of ettringite for specimens submerged in the sulfate solution. CSRE with small cement content was also completely disintegrated after six and nine months of exposure in alkaline and acid environments, respectively. However, the acidic environment did not considerably affect the compressive strength of high cement content RE, and the alkaline environment improved their compressive strength. An exponential relationship was proposed between the compressive strength and the ultrasonic pulse velocity for all specimens. Finally, multi-objective optimization by desirability function was used to minimize the cement content and maximize the compressive strength, simultaneously
  9. Keywords:
  10. Cements ; Acidic Medium ; Alkaline Solution ; Optimization ; Ultrasonic Waves ; Rammed Earth Structures ; Chemical Attack ; Sulfate Environment

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