Enhancing concrete microstructure with carboxymethyl cellulose (CMC) and microcrystalline cellulose (MCC): A comprehensive characterization using FTIR, TGA, and XRD

Abstract

This study examines the effects of carboxymethyl cellulose (CMC) and microcrystalline cellulose (MCC) on the microstructural properties of concrete through Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and X-Ray Diffraction (XRD) techniques. Concrete mixtures with varying proportions of CMC and MCC were prepared to investigate alterations in functional groups, thermal stability, and crystalline phase structure. The FTIR spectra exhibited peak shifts, intensity variations, and structural changes with increasing additive content in the ranges of 3780–3350 cm^-1 (O–H), 1794–1625 cm^-1 (C=O), and 1451–708 cm^-1. TGA and differential thermogravimetric (DTG) analyses revealed that with increasing additive content, decomposition temperatures rose from 433°C to 453°C, while total mass loss increased from 3.34% to 6.05%, indicating modifications in thermal stability. XRD analysis showed that the incorporation of CMC and MCC enhanced crystallinity from 52.42% to 82.60%, with the dominant phases identified as quartz (SiO₂), portlandite (CH), and calcium silicate hydrate (C–S–H). The highest crystallinity value, 82.60%, was recorded in the CMC050 sample.