Effect of Chemical and Mineralogical Composition of Quarry By-Products on Cement-Stabilization Efficiency Using Elastic Wave Signals

Quarry by-products (QB), residual aggregate materials produced from stone quarry operation, present significant challenges due to their substantial annual production volume. Research at the Illinois Center for Transportation (ICT) has explored the sustainable use of QB as a pavement foundation material, revealing that dolomitic QB demonstrates enhanced durability over limestone when subjected to long-term cementitious reactions for multiple years. This study investigates the influence of QB’s chemical and mineralogical characteristics on strength gain behavior during extended cement hydration curing periods. Using the Illinois Department of Transportation (IDOT) aggregate chemical testing procedures, the QB materials were classified as either dolomite or limestone. Further analysis was conducted on the QB materials using X-ray fluorescence (XRF) to determine the detailed chemical composition. Bender Element (BE) sensors, capable of transmitting shear wave signals, were installed in 3% cement-stabilized QB specimens with varying mineralogy and chemical compositions to continuously monitor strength development during the curing process. Specimens were cured at 104 °F (40 °C) for approximately 2 months, simulating long-term cementitious reaction. The findings revealed that limestone QB exhibited a faster hydration rate at the initial curing stage, as indicated by a higher shear wave velocity. However, a reversal trend was observed with continuous curing, where dolomitic QB demonstrated a faster shear wave velocity, suggesting it had a higher hydration rate and increased stiffness. The observation is attributed to the distinct chemical reactions and hydrate formations arising from the inherent mineralogical and chemical difference between QB types.