Appraisal of reclaimed asphalt pavement as coarse aggregates in cement concrete

Abstract

This study explores the performance evaluation of reclaimed asphalt pavement (RAP) as coarse aggregates in concrete construction. The utilization of RAP offers potential economic and environmental benefits by reducing the consumption of natural aggregates, recycling waste materials, and lowering the carbon footprint of construction projects. The review encompasses various aspects related to RAP in concrete, including mechanical properties, durability considerations, testing methods, concrete mix design, performance testing and evaluation, factors affecting performance, RAP content and gradation, processing techniques, use of admixtures and additives, curing conditions, and environmental factors. The findings highlight that RAP concrete exhibits comparable mechanical properties to conventional concrete, while demonstrating improved sustainability through waste reduction and resource conservation. Durability aspects, such as permeability, freeze-thaw resistance, and chloride ion penetration, are also examined, indicating that RAP incorporation can enhance the long-term performance of concrete structures. Testing methods and standards for evaluating RAP in concrete are discussed, emphasizing the importance of reliable and standardized procedures. Concrete mix design incorporating RAP is explored, considering factors such as RAP content, gradation, and processing techniques, including crushing, screening, and blending. The role of admixtures and additives in optimizing RAP concrete properties is also addressed. Moreover, the review delves into the influence of curing conditions and environmental factors on the performance of RAP concrete, underscoring the need for proper curing practices and assessing the impact of temperature, moisture, and exposure conditions. The identified research gaps highlight the need for further investigation, such as long-term studies, understanding the underlying mechanisms, exploring specific environmental factors, establishing standardized testing methods, and considering the economic viability of RAP concrete. Recommendations for future research directions are provided to guide the development of sustainable and efficient construction practices.