Improving the Properties of Soft Soils using Nano-silica, Slag, and Cement

Abstract

Effective utilization of weak soils such as soft clay by imparting additional strength using various stabilization techniques are adopted to enhance the soil behaviour (i.e., bearing capacity) for the construction of roads and/or platforms. Applications of nanomaterials in the field of geotechnical engineering have great potential, for example by promoting the construction of a stronger and stiffer soil skeleton, especially when blended with cementitious materials. Therefore, this paper focuses on studying the effect of nanomodified cementitious binders on the properties of weak soils, which are the most common types of soil in Winnipeg, Manitoba, Canada. The soil selected was soft clay. It was mixed with GU (general use) cement, or slag, or both with different proportions of nano-silica sol (0 to 2.4% of the dried soil weight). The mechanical properties such as the compressive strength at different curing ages and California bearing ratio (CBR) were investigated. Generally, the addition of nano-silica to cement enhanced the properties of the soil in terms of maximum dry density, compressive strength, and CBR. In particular, the bearing ratio for the soil treated with the ternary binder (cement, slag, and nano-silica) was improved. Thus, nano-modified blended cement presents a sustainable and effective stabilizing additive to treat weak soils for the construction of roads with an anticipated measurable impact on reducing the life-cycle cost of repairs due to its projected stability and durability.