Impacts of Coal Char Content and Curing Temperature on Properties of Cement-Stabilized Soil for Transportation Applications

Abstract

Cement soil stabilization is widely used for improving engineering properties of weak soils. It is important to acknowledge the limitations of cement-soil stabilization under various temperature conditions, e.g., cracking at elevated temperatures and limited strength development at low temperatures. Recent studies have explored the use of coal char, a byproduct of pyrolysis, as a potential additive or filler, demonstrating promising results in improving the performance of cement-based construction materials. However, the effects of coal char incorporation on the properties of cement-stabilized soils under different curing temperatures remain unclear. This study investigates the effects of coal char in cement-soil stabilization under four different curing temperatures (i.e., − 23, 5, 20, and 35 ºC). Specifically, the physical properties (i.e., water content, pH, and bulk density), strength, microstructural, and mineralogical properties of cement-stabilized and char-cement-stabilized soils are examined. At low temperatures, − 23 and 5 ºC, the changes in water content, pH, and bulk density are less significant than 20 and 35 ºC for stabilized soils. The compressive strength of char-cement-stabilized soil is higher than that of cement-stabilized soil across various curing times and temperatures. The results of this study demonstrate the promising potential of coal char in enhancing the engineering performance of soil cured at various temperatures, which could improve the performance of transportation structures.