Laboratory performance evaluation of emulsion-based cementitious grouted bituminous macadam for sustainable pavement applications

Cement Grouted Bituminous Macadam (CGBM) is a semi-flexible pavement material that combines the benefits of both flexible and rigid pavements. While CGBM demonstrates excellent rutting resistance compared to conventional bituminous mixes, its fatigue resistance remains inferior. This study investigates the performance of cold mix-CGBM, emphasizing improvements in fatigue behavior. By utilizing an emulsion-based aggregate skeleton, the short-term ageing associated with hot mix aggregate skeleton preparation can be minimized. The cementitious grout for the CGBM was optimized based on its flowability and strength characteristics and was used in both conventional (Asphalt-based) and emulsion-based CGBM. A comprehensive evaluation was conducted to assess various properties, including Marshall stability, compressive strength, Indirect Tensile Strength (IDT), Resilient modulus (MR), Cantabro abrasion, Hamburg Wheel Tracking Test (HWTT), and 4-point flexural beam fatigue tests. Experimental results show that both bitumen-based (B-CGBM) and emulsion-based (E-CGBM) mixes satisfied the mechanical and performance criteria outlined in IRC SP: 125:2019. Notably, the fatigue life of E-CGBM was found to be 1.4 to 2.0 times higher than that of B-CGBM. The energy analysis concluded that the E-CGBM required 29% lower energy than B-CGBM. The adoption of E-CGBM not only enhances fatigue performance but also offers environmental benefits by eliminating the emission of harmful gases associated with hot mix production and lower energy consumption.