加入椰丝纤维对灰渣基地聚合物-土壤固化体失水开裂情况的改善

针对地聚合物固化重金属污染土壤过程中因水分散失带来的最终形态韧性差、脆性大等问题，探究在灰渣基地聚合物-土壤固化体中添加椰丝纤维改善其失水收缩/开裂情况的可行性。通过模拟春夏交替阶段雨水频繁、夏季连续高温下土壤表面干燥开裂变化趋势，对比有无重金属污染下固化体收缩及开裂情况，探究纤维对固化体的力学强化效果。结果表明：受到重金属侵蚀的土壤失水速度高于原状土9.0%,且在25 d试样中其开裂因子相较原状土提高12.9%,收缩率提高34.6%。通过地聚合物进行固化的土壤抗裂性能得到提升，在连续干燥试验中掺入纤维进行优化的地聚合物固化体开裂因子进一步降低，收缩率降低71.3%,开裂因子仅为原状土的4.9%～5.1%。干湿循环条件下，纤维的掺入促使主裂缝消失，四轮干湿循环后最小开裂因子仅为0.0015,地聚合物-椰丝纤维复合改良污染土壤具有较好的抵抗开裂效果。

REMISSION OF MOISTURE LOSS AND CRACKING OF BOTTOM ASH BASED GEOPOLYMER-SOIL SOLIDIFIED BLOCKS BY ADDING COCONUT FIBER

Aiming at the problems of poor toughness and high brittleness of the final shape caused by water loss during the solidification of heavy metal contaminated soil by geopolymer, the feasibility of adding coconut fiber to the polymer soil solidified body in the ash base to alleviate its water loss shrinkage/cracking was explored. By simulating the changing trend of soil surface drying and cracking under the condition of frequent rain in alternate spring and summer and continuous high temperature in summer, the mechanical strengthening effect of fibers was explored by comparing the shrinkage and cracking of solidified blocks with or without heavy metal pollution. The results showed that the water loss rate of soil eroded by heavy metals was 9.0% higher than that of undisturbed soil, the cracking factor increased by 12.9%, and the shrinkage rate increased by 34.6% compared with the undisturbed soil in the 25-day sample. The cracking resistance of soil cured by geopolymer was improved, and the cracking factor of geopolymer cured blocks optimized by adding fiber in continuous drying test was further reduced, the shrinkage rate decreased by 71.3% and the cracking factor was only 4.9% to 5.1% of the undisturbed soil, and the minimum cracking factor was 0.0015 after four cycles of drying and wetting. Geopolymer-coconut fiber composite ameliorated the heavy metal contaminated soil and had a good cracking resistance effect.