Enhancing mechanical and microstructural properties of lateritic soil using bottom ash and cement stabilization: a comparative analysis of destructive and nondestructive testing methods

This study investigates the stabilization of lateritic soil using a blend of bottom ash (BTA) and cement for construction applications. Mechanical properties—unconfined compressive strength (qu), secant elastic modulus (E50), and splitting tensile strength (qt)—were evaluated alongside nondestructive parameters, including P-wave (Vp) and S-wave (Vs) velocities, to estimate dynamic elastic modulus (E0), shear modulus (G0), and Poisson’s ratio (v0). Microstructural analyses revealed dense calcium silicate hydrate (CSH) gels that filled voids and enhanced interparticle bonding. The optimal mix (7% cement + 20% BTA) achieved a qu of 6.64 MPa after 120 days, a 45% increase over cement-only soil. E50 and qt improved by 27.8% and 21.5%, respectively. Vp and Vs rose by 14.5% and 16.3%, reaching 2,430 m/s and 1,520 m/s. E0 and G0 peaked at 12,300 MPa and 4,720 MPa. Strong correlations between wave velocities and strength parameters highlight the potential of nondestructive testing for estimating mechanical properties. The results confirm that BTA significantly enhances strength, stiffness, and durability of stabilized soil, offering a cost-effective and sustainable solution for infrastructure applications.