Performance enhancement and mechanism analysis of low-carbon cement-stabilized macadam based on vibratory mixing method

Abstract

The cement-stabilized macadam (CSM) base demands a large amount of cement. However, cement production results in high energy consumption and CO₂ emissions, thereby posing a threat to the environment. Thus, it is essential to seek solutions to reduce CSM cement usage. Uneven cement dispersion in CSM leads to premature pavement distresses and cement waste. The mixing process becomes a crucial factor to dispersion. This study investigates the performance enhancement mechanism of CSM under different mixing processes (static and vibratory mixing) and cement dosages. The unconfined compressive strength of CSM under various cement dosages and two mixing conditions was evaluated. The indirect tensile strength, dry shrinkage, temperature shrinkage, and anti-scour properties of CSM with the same cement dosage but different vibratory mixing conditions were investigated. The microstructure and cement dispersion uniformity in CSM were analyzed via SEM and EDTA testing. Results show that vibratory mixing destroys cement agglomeration through high-frequency elastic waves, strengthens the interfacial transition zone and improves the mixing efficiency in low-efficiency area, promoting uniform distribution of cement hydrated products and aggregates. Compared with static mixing, it increases unconfined compressive strength by over 20 % under different cement dosages, and leads to improvements in the indirect tensile strength, dry shrinkage, temperature shrinkage, and anti-scour performance of CSM with the same cement dosage. The vibratory mixing process can ensure that the performance remains stable while reducing the cement consumption. It is capable of cutting down carbon emissions and energy consumption, thus being a promising and low-carbon construction method.