Assessment of the Rutting Resistance and Moisture Susceptibility of SMA Mixtures Containing Different Types of Aggregates and Antistripping Additives: A Comparative Study with Limestone and Silica Aggregates

Abstract

Pavement is one of the essential foundational elements of transportation infrastructures. Ensuring the durability and significant quality of pavement surfaces is crucial for both road agencies and users globally. Stone mastic asphalt (SMA) has emerged as a global choice, presenting high quality. SMA mixtures necessitate additives due to their coarse aggregate and bitumen drainage tendencies. This research addresses the challenge of water infiltration compromising bitumen-aggregate bonds to investigate the impact of antistripping nanomaterials on the moisture susceptibility and rutting resistance of SMA by employing limestone and silica aggregates, bitumen, and Evonik and Zycotherm as nanomaterial additives. Various tests on asphalt samples encompassed resilient modulus, indirect tensile strength, dynamic creep, and the Texas boiling test. The results affirmed that these materials act as antistripping additives, successfully reducing the moisture susceptibility of asphalt mixtures. Adding these additives has a less significant effect on limestone aggregates than on silica aggregates because limestone aggregates generally have suitable moisture resistance, and the effect of Evonik on limestone aggregates is negligible. However, these additives improve the performance of silica aggregates against moisture susceptibility. Additionally, the samples with 0.1% Zycotherm and 0.35% Evonik increased the load-bearing capacity of these mixtures due to better bonding between aggregates and bitumen, finally resulting in a thinner pavement design. Therefore, based on comprehensive evaluations in this research, opting for 0.1% Zycotherm proves more advantageous than opting for 0.35% Evonik to optimize SMA properties, which contributes to advancements in sustainable pavement technologies. Pavement is an essential component of roadways, ensuring quality service and durability for road users. However, it faces challenges from loading, traffic, and environmental factors, leading to increased maintenance costs and premature failure. Moisture susceptibility and rutting are two of the gravest issues influenced by various factors and remain significant challenges for pavement engineers. Stone mastic asphalt (SMA) offers promising resistance to deformation and rutting; however, challenges such as drain down persist, emphasizing the importance of bitumen properties and antistripping additives in optimizing pavement performance. By investigating the effectiveness of antistripping nanomaterials on SMA mixtures, this research addresses critical challenges related to moisture susceptibility and rutting resistance in pavements. The results underscore the efficacy of additives, such as Zycotherm and Evonik, in mitigating moisture susceptibility, improving pavement durability and rutting resistant. Through comprehensive evaluations of these additives across different aggregate types—silica and limestone—this study offers practical recommendations for optimizing pavement design and construction practices, providing practical insights into enhancing the performance of asphalt pavements that are particularly valuable for professionals and road agencies.