Historically, whether it was the base or the asphalt layer, it was commonly believed that the use of standard asphalt materials had fulfilled the bonding function. However, these unmodified asphalt materials are unable to meet the requirements for temperature stability and bonding strength, especially under the heavy traffic and heavy axle load conditions of today's expressways. Therefore, in the construction of expressways, SBR composite binder is used as an interlayer bonding material to improve the bonding conditions between structural layers and enhance the interlayer shear strength.

SBR composite binder boasts not only strong interfacial adsorption capabilities but also exhibits a significant intrinsic cohesion within the material itself.

The adhesive oil is primarily used to enhance the compactness of highway asphalt pavement structures, although it is used in small quantities, its role is by no means negligible. During the asphalt pavement adhesive treatment and waterproofing construction on the concrete bridge deck of the Guangzhou North Second Ring Highway (K18+645~K35+012), a large amount of SBR composite binder emulsion was utilized, with a dosage of 0.5kg/m2 and a concentration of 55%.

Core sampling indicates that structures using SBR composite binder as the bonding layer are irregular in shape, and cannot be separated from the upper and lower layers without mechanical cutting, which demonstrates that the bonding strength is no less than that of the mixture itself. Conversely, structures that do not use SBR binder for treatment can easily be separated during the core sampling process.