FT-IR Spectroscopy Combined Infrared Synchrotron Light Improves Micro- and Macroscopic Study of Pavement Subgrade Composite Materials Stabilized Using Polyelectrolytic Polymers

摘要

FT-IR spectroscopy combined infrared synchrotron light micro-spectroscopy (SMIS) advanced techniques were employed to study soil stabilizing mechanisms of two ionic polyelectrolytic polymers (PP1 & PP2) on soil and pavement composite micro- and nanostructures. The main aim of this study was to probe the micro- macroscopic changes in stabilized materials using these non-traditional chemical stabilizers (PP1 & PP2) with the aim to improve their performance. Performance was assessed by measuring strength properties of composite specimens (plasticity index). Analyses of the SMIS spectra of treated samples indicated two prominent changes in vibrations in two regions: Firstly, the 3000 - 1400 cm"1 IR region was probably due to OH deformations of the hydroxyl groups of adsorbed water (1635 - 1600 cm~(-1)), and the expansive property of clay nanostructures; Secondly, in the 1400 - 950 cm~(-1) IR region, possibly due to the Si-0 framework, that is, silicate plates of type T-E or T-O-E, where any new bonding or rearrangement of the silicate tetrahedron molecule in the soil samples would be sensitive. Since statistical analysis showed that these changes were not significant (p<0.05) using conventional spectroscopy, the presence of a surface composite network (interface) binding the particles was observed when infrared synchrotron light spectroscopy was successfully employed to elucidate these changes at the micro scale level and confirmed with macroscopic measurements using HR-SEM. Conclusively, the demonstrated approach is a promising tool to obtain chemical information involved in microcrystalline formation in these kind of polymeric-enhanced complex composite interfaced materials. However, a further study under varied and optimized experimental conditions would provide more insight into the molecular behaviour of such modified composite reinforced materials.