| Abstract: |
One of the most prevalent types of pavement material in flexible road construction is bituminous concrete (BC), which has excellent load-bearing capacity, good durability and environmental degradation resistance. The key volumetric and mechanical properties (i.e., Marshall stability, flow value, air voids, voids in mineral aggregate [VMA], and Voids filled with bitumen); important factors that impact the performance of BC mixes are critically influenced by optimum bitumen content (OBC) and proper integration/blending of graded aggregates. Our comprehensive meta-analysis review paper systematically analyzes past laboratory experiments and parametric studies between 2015-2025 for BC mix designs of variable bitumen percentage (3.5% to 6.5%) with different aggregate gradation including approximately value according Indian Roads Congress(IRC) & Ministry Road Transport Highways(MoRTH). The review brings together results from over 45 experimental investigations conducted using Marshall mix design methodology, and investigates the impact of bitumen content on stability-flow behaviour as well as volumetric properties and moisture susceptibility. Various researchers' laboratory test reports have been critically compared to determine common trends and optimum parameters. The analysis indicates that optimum bitumen content varies between 5.0% and 5.8%, with the maximum Marshall stability value typically falling around a range of bitumen from about to (52-55)% Proper aggregate blending has a great influence on air void distribution and mixture workability. The study also identifies aggregate gradation types (Dense, Semi-Dense and Gap-Graded) which significantly influences mix performance. The results show that deviations from ideal bitumen content cause early distresses like rutting, cracking and stripping. This review is useful for both pavement engineers and researchers in choosing relevant design parameters aimed at enhancing the performance of bituminous pavements under different loading fittings including traffic volume, climate conditions. Recommendations for further studies are provided at the end of the paper, including focuses on recycled materials and warm-mix asphalt technologies. |
