The objective of the present study was to increase the strength and stiffness of silty clay and silty sand subgrades for building economic and sustainable asphalt pavements. Advanced cyclic load tri-axial (ACLT) and California bearing ratio (CBR) tests were performed to obtain the experimental and theoretical resilient modulus (M) of the soil subgrades, respectively. In addition, the impact of the stabilization of the plasticity and compaction characteristics of the soil subgrades was determined. The insight into the mechanism of the stabilization was obtained by determining the mineralogical and microstructural properties of the stabilized soils through X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) tests, respectively. The combined inclusion of 20% brick kiln dust and 20% pond ash resulted in 186% increase in the CBR, 224% increase in the experimental M, 96% increase in the theoretical M, 2.07 times higher pavement service life, 23% savings in cost, and 28% reduction in the CO emissions associated with pavement construction. The enhancement in the CBR and M of the soils was attributed to the increased inter-particle friction, improved particle size distribution in stabilized clay and sand, and a concurrent reduction in the plasticity of clay. The study highlights the real-world usage of the ACLT test to get the real M of soil subgrade rather than the over-estimated theoretical M. For precise estimation of M from CBR, a correlation between CBR and experimental M was established.

中文翻译：

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使用实验和理论方法对工业废物稳定粘土和沙土路基进行经济和环境评估

本研究的目的是提高粉质粘土和粉质砂路基的强度和刚度，以建设经济且可持续的沥青路面。进行高级循环载荷三轴（ACLT）和加州承载比（CBR）试验，分别获得土路基的实验和理论回弹模量（M）。此外，还确定了土路基塑性和压实特性稳定的影响。通过分别通过 X 射线衍射 (XRD) 和扫描电子显微镜 (SEM) 测试确定稳定土的矿物学和微观结构特性，深入了解稳定作用的机制。 20%砖窑灰和20%池塘灰混合掺入，使CBR提高186%，实验M提高224%，理论M提高96%，路面使用寿命提高2.07倍，节省23%成本，以及与路面建设相关的二氧化碳排放量减少 28%。土壤 CBR 和 M 的提高归因于颗粒间摩擦力的增加、稳定粘土和沙子中颗粒尺寸分布的改善以及粘土塑性的同时降低。该研究强调了在现实世界中使用 ACLT 测试来获取土壤路基的真实 M，而不是高估的理论 M。为了根据 CBR 精确估计 M，建立了 CBR 与实验 M 之间的相关性。