Affiliations: School of Civil Engineering and Environmental Science,
University of Oklahoma, 202 West Boyd Street, 334, Carson Engineering Center,
Norman, OK 73019, USA. Tel.: +1 405 325 7993; Fax: +1 405 325 4217; E-mail:
{nkhoury, bgfinch}@ou.edu | College of Engineering, University of Oklahoma, 202
West Boyd Street, 107, Carson Engineering Center, Norman, OK 73019, USA. Tel.:
+1 405 325 2626; Fax: +1 405 325 7508; E-mail: [email protected]
Abstract: A laboratory study was undertaken to investigate the performance of
limestone aggregate base stabilized with different stabilizing agents, namely,
class C fly ash, cement kiln dust and fluidized bed ash. Cylindrical specimens
were compacted and cured for 1 hour, 3 days and 28 days prior to tests of
unconfined compressive strength (UCS), scanning electron microscopy,
energy-dispersive spectrometry and X-ray diffraction. Results showed that the
UCS values increased with curing time. It was also found that the different
stabilizing agents produced different UCS values. The reference intensity ratio
(RIR) method was employed to identify and quantify the mass percent of minerals
and cementing compounds in the mixtures. Results revealed the formation of
cementing compounds such as ettringite, C-S-H, C-A-H and C-A-S-H, which were
responsible for an increase in the UCS values. In this study, the sum of all
the cementing compounds (SCC) showed the same beneficiation trend as the UCS
trend with curing time. Finally, the UCS values correlated fairly well with
SCC. The SEM micrographs showed the intensity of crystal formation and
hydration coating, which increased with curing time and percentage of
additive.
Keywords: Cementitious stabilization, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, unconfined compressive strength, reference intensity ratio
