绿色纤维改性粉煤灰水泥注浆材料宏微观性能研究

Research on Macro and Micro Properties of Green Fiber Modified Fly Ash Cement Grouting Materials

摘要: 为解决煤层底板注浆工程中高掺量粉煤灰水泥材料强度不足、结石体成型性差的双重难题，本文以II级粉煤灰、P·O42.5水泥为基体，3%水玻璃为外加剂，引入聚丙烯纤维(PP)与玄武岩纤维(BF)绿色纤维构建改性体系。固定粉煤灰–水泥质量比7:3、水固比1:1，基于3 d、7 d、28 d实测抗压强度与结石体长度数据，系统探究纤维类型(PP, BF)、长度(3 mm, 6 mm, 9 mm)及掺量(0%, 0.1%, 0.4%, 0.7%, 1.0%)对材料宏微观性能的协同调控效应。通过SANS品牌单轴抗压强度测试机测试宏观强度，游标卡尺测定结石体长度，结合X射线衍射(XRD)定量分析微观物相演变，建立“强度–结石体–微观结构”关联机制。结果表明：PP纤维28 d强度最优配方为3 mm + 1.0%掺量(1.12 MPa，较对照+83.6%)；BF纤维28 d强度最优配方为3 mm + 1.0%掺量(1.00 MPa，较对照+63.9%)；BF纤维7 d强度最优配方为9 mm + 1.0%掺量(0.64 MPa，较对照 + 204.8%)；XRD分析显示，经济型配方(BF6 mm + 0.7%) 28 d龄期核心水化产物C-S-H凝胶(2θ = 28˚~32˚宽化峰)衍射峰强度较对照提升76.9%，未水化C₃S (2θ = 31.0˚)含量降低48.2%，证实纤维通过优化物相组成实现宏观性能协同提升。研究基于实测数据为煤层底板注浆工程提供精准绿色配方，丰富了纤维改性注浆材料的宏微观关联理论。

Abstract: In order to solve the dual problems of insufficient strength and poor formability of high-content fly ash cement materials in coal seam floor grouting engineering, a modified system was constructed by introducing polypropylene fiber (PP) and basalt fiber (BF) green fiber using grade II. fly ash and P·O42.5 cement as the matrix, 3% water glass as the admixture, and polypropylene fiber (PP) and basalt fiber (BF) green fiber. Based on the measured compressive strength and stone body length data of 3d, 7 and 28 days, the synergistic regulation effect of fiber type (PP, BF), length (3 mm, 6 mm, 9 mm) and content (0%, 0.1%, 0.4%, 0.7%, 1.0%) on the macro and micro properties of the material was systematically explored. The macroscopic strength was tested by the SANS brand single-axis compressive strength tester, the length of the stone body was measured by vernier caliper, and the phase evolution of microscopic matter was quantitatively analyzed by X-ray diffraction (XRD), and the correlation mechanism of “strength-stone-microstructure” was established. The results showed that the optimal formulation of PP fiber for 28 days was 3 mm + 1.0% content (1.12 MPa, +83.6% compared with the control). The optimal formula of BF fiber for 28 d strength was 3 mm + 1.0% (1.00 MPa, +63.9% compared with the control). The optimal formulation of BF fiber for 7 d strength was 9 mm + 1.0% (0.64 MPa, +204.8% compared with the control). XRD analysis showed that the diffraction peak intensity of the core hydration product C-S-H GEL (2θ = 28˚~32˚ widening peak) of the economical formula (BF 6 mm + 0.7%) at 28 days was increased by 76.9%, and the content of unhydrated C₃S (2θ = 31.0˚) was reduced by 48.2% compared with the control, confirming that the fiber achieved synergistic improvement of macroscopic performance by optimizing the phase composition. Based on the measured data, this study provides an accurate green formula for coal seam floor grouting engineering, which enriches the macro and micro correlation theory of fiber modified grouting materials.