The Critical Dosage and Performance Evolution Mechanism of Expansive Soil Improved by Rice Husk Ash

Key Points

• This research aims to understand how rice husk ash improves expansive soil and determine its optimal dosage.
• Conducted macro experiments and micro characterization to study rice husk ash improvements.
• Identified a critical value of 25% for effective performance enhancement.
• Analyzed mechanisms including C-S-H gel formation and ion exchange.
• Free expansion rate decreased by up to 79% at 25% ash dosage.
• Shear strength continually increased, peaking at 25% with the best deformation resistance.
• Dosages over 25% led to negative effects, including a return of expansion indicators and decreased marginal strength benefits.