大掺量磷石膏用于路基填料的性能试验研究

Experimental research on performance of high dosage phosphogypsum used as subgrade filler

为探索磷石膏大掺量、规模化、资源化利用路径,分别以自制固化剂和水泥为胶凝材制备大掺量磷石膏路基填料,开展大掺量磷石膏混合料的击实试验、无侧限抗压强度试验及疏水改性试验,分析大掺量磷石膏与自制固化剂和水泥的适配性、击实特性、强度特性、耐水性能。结果表明,采用水泥或自制固化剂改性磷石膏击实曲线呈单峰变化趋势,且含水率偏低时对大掺量磷石膏混合料的干密度影响较小;相同配比时,固化剂体系大掺量磷石膏混合料7d无侧限抗压强度是水泥体系的1.5倍以上,磷尾砂与自制固化剂的适配性优于黏土,且配比为90%磷石膏+10%固化剂的大掺量磷石膏混合料7d无侧限抗压强度度达3.4MPa,经疏水改性后强度提升至4.2MPa,疏水剂与自制固化剂的复配较好地改善了磷石膏自身亲水特性,提升了其水稳性能。

In order to explore the resource utilization path of phosphogypsum,high dosage phosphogypsum subgrade fillers are prepared with self-made curing agent and cement as cementitious materials.The compaction test,unconfined compressive strength test and hydrophobic modification test of high dosage phosphogypsum mixture are carried out to analyze the adaptability,compaction characteristics,strength and water resistance.The results show that the compaction curve of phosphogypsum modified by cement or self-made curing agent shows a single peak change trend,and the low moisture content has little effect on the dry density of high dosage phosphogypsum mixture.At the same proportion,the 7-day unconfined compressive strength of high dosage phosphogypsum mixture in the curing agent system is more than 1.5 times that of the cement system,and the adaptability of the phosphorus tailings and the self-made curing agent is better than that of the clay.The 7-day unconfined compressive strength of high dosage phosphogypsum mixture with the proportion of 90%phosphogypsum and 10%curing agent reaches 3.4MPa,and the strength is further improved to 4.2MPa after hydrophobic modification.The combination of hydrophobic agent and self-made curing agent improves the hydrophilic properties of phosphogypsum and its water stability.