<p>There
is consistent research evidence that shows improvement of the engineering
properties of subgrade soils treated with lime or cement. However, limited
information is available on the effect of climatic changes on the subgrade
stiffness. The thesis studies the effects of changes in soil moisture content
and temperature on the resilient modulus of treated and untreated subgrades in
Indiana. Two types of soils were tested: A-6 and A-7-6, from two locations in
Indiana: Hartford City and Bloomington, respectively. When existing standards
ASTM D559/559-15 and ASTM D560/560-16 for wetting/drying (WD) and
freezing/thawing (FT) processes, respectively, were followed, the treated and
untreated samples failed through the process of preparation due to the
stringent procedures in the standards. Appropriate test conditions were
investigated, as part of the research, to develop new protocols more
appropriate to the field conditions in Indiana. Two new test protocols were developed
and successfully applied to the treated soils. A total of 26 resilient modulus,
M<sub>R</sub>, tests were conducted following the standard AASHTO T307-99. The
M<sub>R</sub> results showed that the repeated action of WD and FT cycles reduced
the stiffness of the chemically-treated soils down to values similar to or
lower than those of the untreated soils. However, when the amount of chemical
was doubled, with respect to the optimum, the M<sub>R</sub> of the treated
soils improved over that of the untreated soils, even after the wetting-drying cycles.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/9757385 |
| Date | 16 October 2019 |
| Creators | Andrea Ardila Quiroga (7332803) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Effect_of_Climatic_Changes_on_Subgrade_Stiffness/9757385 |
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