College of Civil Engineering, Taiyuan University of Technology

【目的】为实现建材行业碳减排和固废资源化利用的目标。【方法】以赤泥和煤系偏高岭土为原料制备地聚合物混凝土,采用正交试验方法研究了4种因素对其力学性能的影响。【结果】方差分析表明,水胶比对赤泥-煤系偏高岭土地聚合物混凝土强度有显著影响,其次是N2O/H2O,养护条件和骨胶比的影响较小。根据试验结果,建立了地聚合物混凝土抗压强度与劈裂抗拉强度的数学模型,方程拟合效果良好。进一步分析得到了地聚合物混凝土的优选配比,养护28d的立方体试件抗压强度和劈裂抗拉强度分别为43.6MPa和2.87MPa.借助低场核磁共振测试对不同水胶比的地聚合物混凝土孔隙结构进行了表征,发现地聚合物混凝土内部以微孔为主,可蒸发的自由水含量增加使得孔隙率增大,孔隙结构粗化,宏观上表现为材料强度的降低。本研究可为地聚合物混凝土的推广与工程应用提供一定的理论指导。

【Purposes】 This work is conducted to achieve the objectives of carbon emission re-duction and resource utilization of solid waste. 【Methods】 Geopolymer concrete was prepared from red mud and coal-metakaolin, and the effect of four factors on its mechanical properties was in-vestigated with an orthogonal test method. 【Findings】 The water-binder ratio was found to have a significant effect on the strength of the geopolymer concrete, followed by Na2O/H2O, while the curing conditions and the aggregate-binder ratio have lesser effect, according to the ANOVA. On the basis of the experimental results, the mathematical model of compressive strength and splitting tensile strength of geopolymer concrete was established, and the fitting effects of the equations were favourable. Further analysis obtained the optimal ratio of geopolymer concrete, and the compressive strength and splitting tensile strengthes of the cube specimens cured for 28 d were 43.6 MPa and 2.87 MPa, respectively. Then, the pore structures of the geopolymer con-cretes with different W/B ratios were characterised with low-field NMR tests. The results indi-cate that the geopolymer concrete is predominantly microporous internally. The increased content of evaporable free water increases the porosity and coarsens the pore structure, which macro-scopically manifests as a reduction in strength of the material. This study can provide some theo-retical guidance for the promotion and engineering application of geopolymer concrete.

国家自然科学基金资助项目(51879180);山西省基础研究计划资助项目(20210302124613);2021年大学生创新创业训练计划项目(NO.21007)

白晓红,薛世强,郭天天,等.基于正交试验的赤泥-煤系偏高岭土地聚合物混凝土力学性能研究[J].太原理工大学学报,2023,54(4):710-715.

BAI Xiaohong,XUE Shiqiang,GUO Tiantian,et al.Research on the mechanical properties of red mud-coal metakaolin geopolymer concrete based on orthogonal tests[J].Journal of Taiyuan University of Technology,2023,54(4):710-715.