Evaluation of interlayer bond strength for C55 emulsion prime bituminous binders with aggregates

Abstract. The use of an environmentally and green friendly product for improved interlayer bond strength in recent times has gained interest in the construction industry. This study investigates the performance of the C55 Emulsion Prime when compared with the conventional MC30 prime in enhancing interlayer bond strength and overall adhesion potency with aggregate particles. The C55 Emulsion Prime is a bituminous-based binder designed to penetrate aggregate layers creating a cohesive bond that improves structural integrity and adhesion potency of the binder with aggregates. Through a series of laboratory tests conducted on the two samples, the study provides detailed results on the penetration depth, interlayer bond strength and application under wet conditions. The test results indicated that the C55 emulsion prime significantly enhanced interlayer bond strength with the G1 dolerite aggregate with notable improvement to moisturized or wet surfaces. The C55 Emulsion Prime demonstrates superior interlayer bond strength compared to MC30 Cutback Bitumen Prime in wet regions or when dry aggregate condition is not feasible. The C55 Emulsion prime has a rapid curing rate within 60mins of application to a wet surface making it an efficient protective layer over granular surfaces to adhere and form a good bond strength property with the asphalt layer. This superiority is evident in both the direct shear test, rolling bottle tests, penetration power test and Zeta Potential test making C55 Emulsion Prime a more reliable choice for enhancing pavement performance in accordance with environmental friendliness and climate change sequences. Furthermore, the adhesive strength of the emulsions can be determined by identifying the isoelectric point (IEP). IEP is the pH condition where the surface charge = 0 mV. The IEP of C55 is approximately at pH 4.1. The IEP of the MC30 has been extrapolated to be approximately at pH 2.1. Material where the IEP is at higher pH form the strongest bond because they have a high proton acceptability. It can be predicted that the C55 forms a stronger bond with the aggregate when compared to MC30.