سيداميرحسين فاطمي

In recent years, due to the growing importance of reducing energy consumption and minimizing the environmental impacts associated with hot mix asphalt, cold mix asphalt has garnered attention as an eco-friendly alternative. By lowering fuel usage and greenhouse gas emissions during production and application, cold mix asphalt is considered an effective strategy toward sustainable development. However, limitations such as slow curing rates, low early strength, and sensitivity to environmental conditions have challenged the widespread implementation of this technology. This study aims to investigate the effect of curing conditions on the performance characteristics of cold mix asphalt containing different fillers and seeks to provide practical solutions to enhance the performance of these mixtures. For this purpose, various cold mix asphalt samples were prepared using fillers such as hydrated lime, microsilica, and ground granulated blast-furnace slag (GGBS). These samples were subjected to different curing temperatures—ambient temperature and 60°C—and various curing durations of 24 hours, 7 days, and 14 days. Performance eva‎luation included Marshall stability, indirect tensile strength (ITS), tensile strength ratio (TSR), semi-circular bending (SCB), and dynamic creep tests. The results demonstrated that microsilica provided superior mechanical performance compared to other fillers. In the Marshall stability test, the sample containing microsilica (CMA 2), cured at 60°C for 14 days, achieved a maximum stability of 19.26 kN. In the ITS test under the same conditions, this sample exhibited a tensile strength of 316.8 kPa, outperforming the hydrated lime (229 kPa) and GGBS (301 kPa) samples. Furthermore, in the moisture sensitivity test, the TSR for the microsilica-containing mixture under optimal curing conditions was 90.02%, indicating higher moisture resistance. In the SCB test, this sample recorded the highest cracking resistance index (1796.25) among the cold mix samples. Additionally, in the dynamic creep test, the microsilica-containing mixture showed the highest flow number of 5545, demonstrating excellent resistance to permanent deformation. These findings suggest that using microsilica under appropriate curing conditions leads to the production of durable cold mix asphalt with enhanced environmental resistance and reduced curing time. The results support the broader application of cold mix asphalt in road construction projects—especially in specific climatic conditions or projects with time constraints—while also contributing to reduced construction costs and environmental impacts.

مخلوط آسفالت سرد , عمل آوري , آهك هيدراته , ميكروسيليس , سرباره آهن , خواص مكانيكي , پايداري حرارتي , مقاومت كششي , حساسيت رطوبتي , خزش ديناميكي

Cold mix asphalt , Curing , Hydrated lime , Microsilica , Ground granulated blast-furnace slag , Mechanical properties , Thermal stability , Tensile strength , Moisture susceptibility , Dynamic creep

Seyyed Amirhossein Fatemi

Dr. Neda Kamboozia