A comparative study on the workability, mechanical properties and microstructure of cemented fine tailings backfill with different binder

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials Pub Date : 2024-11-15 DOI:10.1016/j.conbuildmat.2024.139189

Lei Zhang , Lijie Guo , Shaoqing Liu , Xiaoming Wei , Yue Zhao , Mengyuan Li

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Abstract

With the increasingly prominent problems of cement cemented fine tailings backfill (CFTB), the demand for higher performance, economical, and low-carbon new binder is constantly increasing. This paper comparatively studies the workability and mechanical properties of ordinary Portland cement (PC) and two types of new binders (SC and SGL) CFTB. Additionally, the microstructural and gel products of CFTB are analyzed by hydration heat, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), thermos-gravimetry (TG), and mercury intrusion porosimetry (MIP). The results reveal that compared to CFTB-PC, CFTB-SC and CFTB-SGL exhibit reduced fluidity and bleeding rates, alongside increased yield stress and plastic viscosity. CFTB-PC sets and hardens rapidly, but its uniaxial compressive strength (UCS) increases slowly. CFTB-SC and CFTB-SLG set and harden more slowly than CFTB-PC, but their UCS increases more rapidly. The 3 d UCS of CFTB-SC and CFTB-SGL surpasses that of CFTB-PC, and the 7 d-360 d UCS reaches 1.66–2.66 times that of CFTB-PC. The 3 d-14 d UCS of CFTB-SC is lower than that of CFTB-SGL, but the 28 d-360 d UCS is 13.78 % higher than that of CFTB-SGL on average. The hydration rate and total hydration heat release follow the order PC > SC > SGL. The hydration products of CFTB-PC mainly consist of fibrous C-S-H gel with unidirectional distribution, while those of CFTB-SC and CFTB-SGL are characterized by foil-like C-S-H gel with three-dimensional non-directional distribution and needle bar-like ettringite with skeleton support function, facilitating closely embedded with fine tailings. The pores in CFTB-PC are predominantly large pores (d ≥ 1000 nm), whereas those in CFTB-SC and CFTB-SGL are mainly transition pores (10 nm ≤ d < 100 nm) and capillary pores (100 nm ≤ d < 1000 nm). The research results provide theoretical guidance for the development of new filling binder.

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使用不同粘结剂的胶结尾矿回填的工作性、机械性能和微观结构比较研究

随着水泥胶结尾矿回填（CFTB）问题的日益突出，对高性能、经济、低碳的新型粘结剂的需求不断增加。本文比较研究了普通硅酸盐水泥（PC）和两种新型粘结剂（SC 和 SGL）CFTB 的工作性和机械性能。此外，还通过水化热、扫描电子显微镜（SEM）、能量色散光谱仪（EDS）、X 射线衍射（XRD）、热重分析（TG）和汞侵入孔隙分析（MIP）分析了 CFTB 的微观结构和凝胶产物。研究结果表明，与 CFTB-PC 相比，CFTB-SC 和 CFTB-SGL 的流动性和出血率降低，屈服应力和塑性粘度增加。CFTB-PC 固化和硬化速度快，但其单轴抗压强度（UCS）增加缓慢。CFTB-SC 和 CFTB-SLG 的凝固和硬化速度比 CFTB-PC 慢，但它们的单轴抗压强度增加得更快。CFTB-SC 和 CFTB-SGL 的 3 d UCS 超过了 CFTB-PC，7 d-360 d UCS 达到了 CFTB-PC 的 1.66-2.66 倍。CFTB-SC 的 3 d-14 d UCS 低于 CFTB-SGL，但 28 d-360 d UCS 平均比 CFTB-SGL 高 13.78 %。水合速率和总水合放热量遵循 PC > SC > SGL 的顺序。CFTB-PC 的水化产物主要是单向分布的纤维状 C-S-H 凝胶，而 CFTB-SC 和 CFTB-SGL 的水化产物则是三维非定向分布的箔状 C-S-H 凝胶和具有骨架支撑作用的针条状埃特林岩，有利于与细尾矿紧密嵌合。CFTB-PC 中的孔隙主要为大孔隙（d ≥ 1000 nm），而 CFTB-SC 和 CFTB-SGL 中的孔隙主要为过渡孔隙（10 nm ≤ d < 100 nm）和毛细管孔隙（100 nm ≤ d < 1000 nm）。研究成果为新型填充粘结剂的开发提供了理论指导。

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来源期刊

Construction and Building Materials 工程技术-材料科学：综合

CiteScore

13.80

自引率

21.60%

发文量

3632

审稿时长

82 days

期刊介绍： Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged. Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.