چكيده به لاتين
Roller-compacted concrete pavements (RCCP) offer a competitive advantage over high-performance asphalt pavements due to their high compressive strength, adequate durability, low maintenance costs, and longer lifespan. Researchers have continually sought to enhance the mechanical properties of RCC pavements to achieve greater durability and strength. Consequently, there is an ongoing exploration of alternative solutions aimed at improving the performance of RCC pavements. One such solution is the use of emulsion asphalt. However, research on the application of emulsion asphalt in roller-compacted concrete has been more limited, primarily focusing on conventional concrete. Additionally, one of the most critical topics in pavements is the subject of fracture mechanics in all loading modes and the examination of crack growth behavior. The principles of fracture mechanics for analyzing cracking in both Portland and roller-compacted concrete have predominantly addressed tensile modes. However, these types of pavements, similar to other asphalt mixtures, experience various loading conditions, including tensile and shear loading modes throughout their service life. Given the scarcity of research on pure tensile loading and fracture behaviors in roller-compacted concrete with varying percentages of cationic emulsion asphalt, this study aims to investigate the fracture mechanics of roller-compacted concrete under the mentioned loading modes. To this end, samples were created using ENDB, allowing for the assessment of the fracture resistance of roller-compacted concrete. After fabricating samples with different percentages of emulsion asphalt (0%, 3%, 6%, and 9%), the critical failure load and fracture toughness values were determined. Furthermore, in roadway pavements, durability against freeze-thaw cycles is of paramount importance, a topic also addressed in this research. The findings indicate that increasing the amount of emulsion asphalt leads to a lesser reduction in resistance during repeated cycles. Based on analyses, the primary reason for this phenomenon is attributed to the reduced permeability of concrete samples containing higher emulsion asphalt proportions. The data and results reveal that the initial addition of emulsion asphalt to roller-compacted concrete samples results in a decrease in fracture toughness. However, results also indicate that as the percentage of emulsion asphalt increases from 3% to 9% in the first pure mode, the fracture toughness increases, with the highest fracture toughness noted at 9% emulsion. A similar trend is observed in the third pure mode, demonstrating the positive effect of increasing emulsion content on fracture toughness.
