This research presents the results on an experimental investigation to identify the Significant factors Influencing horizontal cracking in continuously reinforced concrete pavements (C RC P). An In-dcpth analysis of the microstructure, morphological characteristics of the interfacial transition zone (lTZ) and the observation of cracking using the environmental scanning electron microscope (ESEM) was done. Characterization of oxides using Fourier transform infrared spectroscopy (FTlR) and electron dispersive x~ray spectroscopy (EDS) was also performed. Water to cement ratio (We) and rebar temperature had a significant influence on the rebar-concrctc bond strength. The 28-day shear strength measurements showed an increase in rebar-concrete bond strength as the water to cement ratio (w/c) was reduced from 0.50 to 0.40. There was a reduction in the peak pullout load as the temperature increased from 14°F to 252°F for the corroded and non-corroded rebar experiments. The corroded rebar pullout test results showed a 20-50 % reduction in bond strength compared to the non-corroded rebars. FTlR measurements indicated a presence of lcpidocrocrite (y -FeOOH) and maghemite (y -Fe2O3) on the ITZ. ESEM images showed the existence of microcracks as early as three days after casting with the bridging of these cracks between coarse aggregate locations in the interfacial zone propagating through the mortar.
(Kode: UMI Number: 1463575) Rak Penelitian 2