Rock Wool Fiber-Reinforced and Recycled Concrete Aggregate-Imbued Hot Asphalt Mixtures: Design and Moisture Susceptibility Evaluation

Abstract

Designing asphalt mixtures for pavement construction by controlling the moisture-mediated damage remains challenging. With the progression of time, this type of damage can accelerate deterioration via fatigue cracking and rutting unless inhibited. In this study, two types of hot asphalt mixtures (HAMs) were made by incorporating recycled concrete aggregates (RCAs), which were reinforced with rock wool fibers (RWFs). The first specimen was a normal mixture with a completely virgin aggregate, and the second one was a sustainable mixture with 30% RCAs. The proposed mixes were thoroughly characterized to assess the impact of RWF incorporation at various contents (0.5, 1, 1.5, and 2%) on moisture resistance. The optimal asphalt concentration (OAC) and volumetric parameters of the mixes were determined using the Marshall technique. The moisture susceptibility of the obtained HAMs was evaluated in terms of the tensile strength ratio (TSR). The results revealed that the moisture resistance, Marshall stability, flow, and volumetric parameters of the HAMs were improved due to the reinforcement by RWFs, indicating a reduction in the moisture sensitivity and an increase in TSR%. In addition, the HAMs designed with 1.5% RWFs displayed the highest TSR% (11.37) and Marshall stability compared to the control mix. The observed improvement in the moisture resistance and Marshall attributes of the prepared HAMs was ascribed to the uniform distribution of the RWFs that caused a well-interconnected structure and tightening in the asphalt concrete matrix. It is asserted that the proposed HAMs can be nominated for the construction of durable high-performance pavements.

Keywords

• moisture susceptibility
• hot asphalt mixtures
• rock wool fibers
• recycled concrete aggregates
• tensile strength ratio