YANG L, LIU Z, LUO S Q, et al． Mechanism of the effect of naphthalene-based high efficient water reducing agent on the properties of red mud-based cementitious materials［J］. Journal of Henan Polytechnic University( Natural Science)， doi: 10.16186/j.cnki.1673-9787.2024010056.

doi: 10.16186/j.cnki.1673-9787.2024010056

Received： 2024-01-24

Revised： 2024-05-21

Online： 2025-12-11

Mechanism of the effect of naphthalene-based high efficient water reducing agent on the properties of red mud-based cementitious materials (Online)

YANG Lei^{1, 2}, LIU Zhuo^{1, 2}, LUO Shuqiong^{1, 2}, Xie Yufen^{1, 2}

1. School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China；2. Henan Key Laboratory of Materials on Deep-Earth Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China

Abstract: Objectives Red mud has the issue of high water absorption due to its fine particles, so its incorporation will significantly reduce the fluidity and mechanical properties of cement concrete. Some researchers have applied Naphthalene-based high-efficiency water reducing agent (NSF) to red mud based cementitious materials to study its influential rule, buts action mechanism requires to be further clarified. Methods NSF was used as an admixture, experiments on the effects of NSF on the rheological properties, hardening properties and microstructure of red mud-cement pastes with different dosages of red mud were carried out, and mechanism on the effects of NSF on the physical and chemical properties of red mud-cement pastes was revealed. Results Results show that, under the condition of 0.5% NSF saturated doping, the incorporation of NSF improved the fluidity of the slurry, effectively reduced its slump loss at 30 and 60 min, and at the same time, it also reduced the plastic viscosity and shear stress, and improved the dispersion of the red mud-cement particles. When the content of red mud was 0% and 25%,the compressive strength of red mud-cement slurry with NSF was higher than that of samples without NSF at 1, 3, 7 and 28 d, This is because the blending of NSF promotes the hydration reaction of both C₂S and C₃S. The C-S-H in all samples was fibrous and reticulated, and the calcium hydroxide (Ca(OH)₂) was in the form of flakes, . Comparatively, the distribution of Ca(OH)₂ was more homogeneous in the samples with NSF. When the content of red mud was 50%, it will have a negative impact on the strength of the slurry, which may be caused by the high alkalinity of the slurry due to the large dosage of red mud, and the instability of NSF when it acts on the highly alkaline solution. Conclusions These results will provide theoretical guidance for the improvement of the properties of red mud based cementitious materials.

Key words: red mud based cementitious material; naphthalene high efficient water reducing agent; rheological properties; action mechanism