西非砾质红土粒料掺砂改良及水泥稳定处置研究

Improvement of Gravelly Laterite and Cement Stable Disposal in West Africa

西非砾质红土粒料存在颗粒组成不良、液限与塑性指数偏高的现象,限制了该典型地材在道路结构中的应用。该文通过对多种红土粒料以及掺砂改良前后的颗粒组成、界限含水率、CBR试验进行研究,结果表明:掺砂改良可以改善砾质红土粒料级配,提高密实度,降低塑性指数,改良后的砾质红土可满足道路底基层、垫层及基层的使用要求。水泥稳定处置可提高西非红土粒料的力学特性。试验结果表明:水泥剂量与砂掺量对无侧限抗压强度影响明显,砂掺量存在最佳用量范围,2.5%水泥剂量的PK58水泥稳定掺砂红土粒料和3.5%水泥剂量的PK6水泥稳定掺砂红土粒料可满足西非地区倒装结构中垫层材料使用要求。对西非地材的属地化设计与优化改良,可以扩大典型地材的使用范围、提升使用层次,为中国在西非地区的道路工程项目建设提供借鉴。

Owing to poor gradation and high liquid limit and plasticity index,the application of gravel laterite on road paving is limited in West Africa.To overcome this issue,laterite granule combined with sand at different content was explored.The performance including the particle composition,limit water content and CBR value was investigated.The results indicate that sand treatment can improve the gradation,enhance the compactness,and reduce the plasticity index.The improved gravel laterite can meet the requirements of subbase,cushion,and base courses.Cement treatment can improve the mechanical properties of laterite grains.Cement and sand content affect the unconfined compressive strength significantly,with an optimal sand content range identified.Specifically,laterite granules mixed with sand and stabilized with 2.5%PK58 cement and 3.5%PK6 cement meet the specifications for cushion layer materials in inverted structures in West Africa.The overall findings contribute to localization design and the optimization of indigenous materials in West Africa,broadening their application scope and enhancing their use in construction projects,offering valuable insights for Chinese engineering projects in West Africa.