Abstract

Masonry structures are common throughout the world. Adobe is a masonry material found in the southwestern states of the United States in residential structures. Adobe is mostly used in brick form, where locally collected sand, clay, and silt are combined with natural fibers and water to create unfired bricks. The natural fibers provide the primary reinforcement of these bricks, and aid in the drying process, helping the bricks dry evenly. While this material has been used as a residential building material for many hundreds of years, much is still not understood regarding its mechanical properties, as they are dependent on many factors. The research presented here investigates the mechanical properties of adobe bricks, prisms, and walls with respect to moisture content, fiber type, and fiber content used during construction. Additionally, two masonry walls constructed from concrete masonry units (CMU) were tested to investigate the differences in masonry wall behavior with respect to joint reinforcement. These investigations were completed using digital image correlation (DIC) to measure surface deformations during testing. An analysis of these deformations was completed to determine mechanical properties such as strain, shear strain, and displacement. The adobe bricks and prisms were tested in compression while both types of walls were loaded laterally to test in-plane shear strength. From the results of the adobe tests, it was possible to determine correlations between moisture content and the modulus of elasticity of the compression specimens. Additionally, wall analysis provided insight into wall behavior under lateral load. The major findings of this thesis are:

  1. DIC is effective in measuring strain across masonry specimens.
  2. As moisture content increases in adobe bricks and prisms, the modulus of elasticity and strength decreases.
  3. Fiber type and content do not appear to have a correlation to modulus of elasticity of adobe bricks and prisms.
  4. Adobe walls with a door present behave as two independent walls with rocking behavior.
  5. Adobe walls with a window present behave as a 1-piece rigid-body with rocking.
  6. CMU walls with continuous reinforcement reach higher peak loads and exhibit more ductile behavior after peak load.
  7. CMU walls with spliced reinforcement show higher strains in more locations across the wall.

The portion of this research related to adobe brick is supported in part by the National Science Foundation (NSF) under NSF Cooperative Agreement Number EEC-1449501. Any opinions, findings and conclusions, or recommendations expressed in this material are those of the author(s), and do not necessarily reflect those of the NSF.

Date of publication

Spring 5-17-2021

Document Type

Thesis

Language

english

Persistent identifier

http://hdl.handle.net/10950/3748

Committee members

Dr. Michael McGinnis Ph.D. P.E., Dr. Michael Gangone Ph.D., Dr. Gokhan Saygili Ph.D. P.E.

Degree

Master of Science in Civil Engineering

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