ABSTRACT

In Jordan, three major steel-manufacturing factories dump their by-product, recycled steel, randomly in open areas creating environmental hazards. This study intended to evaluate the effectiveness of using a By-product Recycled mill Scale (BRS) in improving the geotechnical properties of high-plastic subgrade soil. The efficacy of the BRS was judged by the improvement in the consistency limits, compaction, free swell, Unconfined Compression Strength (UCS), and the California bearing ratio (CBR). Results showed that BRS additives reduced the plasticity index and the free swell, increased the UCS, the maximum dry density, and the CBR values. Cementitious materials (lime and cement) were added to the subgrade soil that was stabilised with 20% BRS for pavement's subbase applications. Resilient modulus (M_R) was performed using Repeated Load Triaxial (RLT) device to evaluate the resilient response of laboratory-moulded stabilised specimens under cyclic loading. The results showed that the cement-BRS-stabilised soil specimens showed the highest improvement. As a conclusion, BRS showed a positive effect on the geotechnical properties of the soil and it can be used as an additive to improve the geotechnical properties of the subgrade soil and thence solve the BRS disposal problem.

摘要

在约旦，三大钢铁制造厂将其副产品回收钢随意倾倒在开放区域，造成环境危害。本研究旨在评估使用副产品回收磨屑 (BRS) 在改善高塑性路基土的岩土特性方面的有效性。BRS 的功效通过稠度限制、压实度、自由膨胀、无侧限抗压强度 (UCS) 和加州承载比 (CBR) 的改进来判断。结果表明，BRS添加剂降低了塑性指数和自由膨胀，增加了UCS、最大干密度和CBR值。将水泥材料（石灰和水泥）添加到用 20% BRS 稳定的路基土壤中，用于路面的底基层应用。弹性模量 ( M _R) 使用重复载荷三轴 (RLT) 装置进行，以评估实验室成型稳定试样在循环载荷下的弹性响应。结果表明，水泥-BRS 稳定的土样表现出最大的改善。综上所述，BRS对土壤岩土特性有积极作用，可作为添加剂改善路基土的岩土特性，从而解决BRS处理问题。