Ji Zhangrong, Chen Kaisheng, Chen Jinxiong
School of Civil Engineering, Guizhou University, Guiyang, Guizhou, China.
Sci Rep. 2025 Mar 22;15(1):9996. doi: 10.1038/s41598-025-94433-z.
Phosphogypsum can be used for mine filling, ecological restoration materials, road construction materials, soil conditioning agent, cement retarder, etc., the comprehensive utilization rate of only about 40%, less than 10% for road construction materials, for the huge demand for raw materials road projects, obviously a drop in the bucket. In order to solve the accumulation problem of phosphogypsum, this paper closely combines the major needs of national highway construction, actively responds to the call of Guizhou Provincial People's Government and Guiyang Municipal People's Government on the comprehensive utilization of phosphogypsum resources, and researches the strength decay law of cement-stabilized phosphogypsum materials under dry-wet cycle, considering the complex climatic characteristics of dry-wet cycle with the prerequisite of high phosphogypsum mixing, and reveals the mechanism of strength decay, and establishes a strength regression model, and discusses the suitability as pavement base (sub-base) materials. The strength regression model was established, and the suitability of cement stabilized phosphogypsum as the base layer (sub-base layer) of pavement was discussed. The results show that the unconfined compressive strength of cement-stabilized phosphogypsum material decreases with the increase of the number of dry and wet cycles, and the decay is faster in the first four dry and wet cycles, and then gradually tends to level off. The unconfined compressive strength and the number of wet and dry cycles can be fitted with a negative exponential function, and the fitting parameters are all greater than 0.98 . Cement dosage had the most significant effect on unconfined compressive strength with F-value = 988.407, followed by the number of wet and dry cycles and compaction had the least effect. The maximum values of RMSE and MAE were 0.0862 and 0.0776 for the multifactorial regression equation of the unconfined compressive strength of cement-stabilized phosphogypsum materials, which indicated that the regression model had a high reliability. Through the research in this paper, cement stabilized phosphogypsum materials can be used as the base layer (sub-base layer) for highway pavements of various grades under different cement mixing amounts and different traffic volume conditions.
磷石膏可用于矿山充填、生态修复材料、道路建筑材料、土壤改良剂、水泥缓凝剂等，综合利用率仅约40%，用于道路建筑材料的比例不到10%，对于需求巨大的道路工程原材料而言，显然是杯水车薪。为解决磷石膏堆积问题，本文紧密结合国家公路建设的重大需求，积极响应贵州省人民政府和贵阳市人民政府关于磷石膏资源综合利用的号召，在高磷石膏掺量的前提下，考虑干湿循环的复杂气候特征，研究水泥稳定磷石膏材料在干湿循环作用下的强度衰减规律，揭示强度衰减机理，建立强度回归模型，并探讨其作为路面基层（底基层）材料的适用性。建立了强度回归模型，并讨论了水泥稳定磷石膏作为路面基层（底基层）的适用性。结果表明，水泥稳定磷石膏材料的无侧限抗压强度随干湿循环次数的增加而降低，前四个干湿循环中衰减较快，之后逐渐趋于平缓。无侧限抗压强度与干湿循环次数可用负指数函数拟合，拟合参数均大于0.98。水泥剂量对无侧限抗压强度影响最为显著，F值=988.407，其次是干湿循环次数，压实度影响最小。水泥稳定磷石膏材料无侧限抗压强度多因素回归方程的RMSE和MAE最大值分别为0.0862和0.0776，表示回归模型具有较高的可靠性。通过本文研究，水泥稳定磷石膏材料在不同水泥掺量和不同交通量条件下，可作为各级公路路面的基层（底基层）。
