Microcementation Mechanism of Sandy Loess Reinforced with a Cellulose Curing Agent.

Compared with typical and clay loess, sandy loess has a higher sand content and poor geotechnical engineering properties, and it easily causes geological disasters. Sandy loess reinforced with a mixture of sodium carboxymethylcellulose (CMC) + polyacrylamide (PAM) was proposed to improve the structural stability of sandy loess and reveal the curing mechanism of cellulose curing agents. The variations in the shear strength of sandy loess before and after reinforcement were analyzed through a direct shear test. The effects of the concentration of the CMC + PAM curing agent on the shear strength of sandy loess were examined. Subsequently, the soil mass before and after the reinforcement were analyzed through scanning electron microscopy, energy-dispersive spectrometry, Fourier transform infrared spectroscopy, and Xray diffraction to reveal the micromechanism of sandy loess reinforced by the CMC + PAM curing agent. Results showed that with the increase in curing agent concentration, the shear strength of sandy loess increased considerably and gradually stabilized. When the CMC + PAM curing agent was added to natural sandy loess, the abundant hydrophilic groups in CMC and PAM bonded and adsorbed the sand particles in the soil through intermolecular forces. Large aggregates were formed after compact inlaying in the face-to-face contact mode. The porosity of sandy loess decreased, and its structural stability improved. These research conclusions can provide theoretical references for sandy loess reinforcement by cellulose curing agents. [ABSTRACT FROM AUTHOR]