Analyses of the surfaces of concrete by Raman and FT‐IR spectroscopies: comparative study of hardened samples after demoulding and after organic post‐treatment

Abstract

Concrete surfaces were studied by two spectroscopic techniques, FT-IR (in ATR mode) and Raman, to establish a nondestructive method to analyze the distribution of hydrated and organic phases. The surface composition of ordinary clinker, polished concrete, concrete after demoulding, and coated concrete as used in building construction was studied. The clinker's mineral phases and the polished concrete were first analyzed by Raman spectroscopy to determine a spectrum database of the specific phases located on the surface of the concrete. Then, both spectroscopic techniques were used to analyze, directly, the surface of hardened concrete after demoulding. No impact of roughness or porosity was highlighted using Raman spectroscopy; many cementitious, or hydrated phases (alite, belite, tricalcium aluminate, ferrite, portlandite and ettringite) were clearly identified. FT-IR in ATR mode only identified some hydrated phases: portlandite and CaO-SiO 2 -H 2 O (C-S-H), but organic residues from the demoulding oil were characterized by this technique. Furthermore, the convenience of using these techniques together was tested by analyzing the composition of concrete surfaces coated by different organic post-treatments. FT-IR spectroscopy was useful to identify the main organic groups at the concrete surface, whereas Raman spectroscopy was especially able to characterize the mineral/hydrated phases under a thick post-treatment layer (constituted of polyester varnish). Due to their own specificities, these complementary techniques should be used together to easily identify all the mineral phases and organic residues/coatings on concrete surfaces.

Processing and Characterization of PET Composites Reinforced With Geopolymer Concrete Waste

“…The T-GWC samploes presented the new absorption bands of the OA in the regions at 713 cm -1 (C- [19][20][21][22][23][24][25][29][30][31][32][33][34] . Table 4 summarizes these results.…”

“…The crystallinity degree (X c ) of the PET matrix in the composites treated with oleic acid was lower than no treatment composites. Probably, the long chain of OA, anchored onto the fillers and polymer chain hampered the better crystallization 28,29 . This result is in accordance with the better processability and dispersion of fillers observed by FEG-SEM microscopy.…”

Overview about the use of Fourier Transform Infrared spectroscopy to study cementitious materials

“…This specific ability can be useful to: (i) investigate the bulk of lightweight mortar containing aggregates made of polymer waste; (ii) detect residues of demolding agents (e.g. based on vegetable base oil) [20]; (iii) highlight the presence of CaCO 3 efflorescences [21]; (iv) study the interface between concrete and protective coating [21]. Indeed, FT-IR spectroscopy in transmission mode was used to study the bulk of lightweight mortar containing polyamide waste powder.…”

Basic Physical – Mechanical Properties of Geopolymers Depending on the Content of Ground Fly Ash and Fines of Sludge

“…The band at 1 652 cm −1 comes from trace amount of water (bending vibration of H-O-H). The strong peak at 1037 cm -1 is due to the Si-O-Si and Al-O-Si asymmetric stretching vibration [26]. In the case of geopolymer sample T1, it is shifted to lower frequency value (1026 cm -1 ) .…”