Seven Iowa fly ashes were evaluated as a construction material for embankments. Test specimens were molded at optimum moisture content for standard AASHO density and moist cured at 71°F for 28 and 120 days. Six of the fly ashes gave unconfined compressive strengths between 42 and 665 psi after 28 days curing plus one day immersion in water. Test specimens were also steam cured in an autoclave to find a possible quick way to evaluate the strength producing characteristics of a fly ash. The strengths obtained after curing for one day in the autoclave give an indication of the strengths that may be obtained at ordinary curing temperature for longer periods. X-ray diffraction patterns of the fly ashes are included. The peaks show that the reactivity of the fly ashes without lime is related to the amount of free lime present in the fly ash. The fly ashes tested could be used in the construction of embankments. Some of them developed enough strength to warrant their use in the construction of subbases and subgrades for roads. The low strengths obtained with some fly ashes may be improved, if needed, by the addition of lime.
Proceedings of the Iowa Academy of Science
©1962 Iowa Academy of Science, Inc.
Mateos, Manuel and Davidson, Donald T.
"Cementitious Properties of Some Iowa Fly Ashes Without Lime Additives,"
Proceedings of the Iowa Academy of Science, 69(1), 362-369.
Available at: https://scholarworks.uni.edu/pias/vol69/iss1/58