## 1 Introduction  
Modern, advanced construction structures require high-performance waterproofing technology to prevent water leakage for the purpose of maintaining long-term safety and continuous performance. Therefore, research for the development of high-performance waterproofing materials and construction methods that can meet future smart construction structures is continuously being conducted in the waterproofing industry [1]. Recently, in construction sites, composite waterproofing sheets reinforced by laminating a coating and sheet material to replace the existing single ply waterproofing layer is attracting attention as a relatively new waterproofing technology [2]. The manufacturing method of such a composite waterproofing sheet is largely divided into two processs; one is a method of making a waterproof layer by combining a coating-type material such as curable urethane or non-curable synthetic rubber gel with a sheet-type material such as an improved asphalt sheet or synthetic polymer-based sheet at a factory or site. The other is a method to manufacture the waterproofing layer by impregnating and combining synthetic rubber gels and asphalt compounds on both sides with a core material [3]. According to the research and field application verification results, these composite waterproofing layers are 3-4 times larger than the existing single waterproofing layer in terms of structural behavior response, temperature stability, water pressure resistance, and durability [4]. In particular, among these composite waterproofing sheets, in which a non-hardening viscoelastic synthetic polymer-based rubber gel (hereinafter referred to as NHV-SPRG) composite waterproofing sheet) and asphalt compound, etc., is impregnated on both sides with a non-woven fiber reinforcement is preferred as new waterproofing technology [5]. Due to these advantages, NHV-SPRG are actively used not only in Korea, but also in Southeast Asian countries such as Vietnam and Singapore. In particular, in China, quality control of composite waterproofing sheets is managed based on their own standard such as JC/T 2428-2017 \"Non-curable rubber modified asphalt coating for waterproofing\" as a new waterproofing material [6]. An essential performance evaluation item for the field application of composite waterproofing sheets is an adhesion test that confirms satisfactory adhesion between the waterproofing layer and the concrete substrate surface. The installation method of composite waterproofing materials involves rigid or semi-rigid attachment methods in which the composite waterproofing layer is attached to the surface of a concrete structure with a synthetic resin-based adhesive, asphalt-based adhesive, or polymer cement-based adhesive [6]. In general, performance evaluation methods and quality standards for hard or semi-rigid attachments are commonly used in many countries such as ASTM, JIS, and KS. However, it is difficult to find an adhesion test method or quality standard for a non-rigid or soft waterproof layer, which are commonly associated with that of NHV-SPRG. Therefore, it is difficult to evaluate and quantitatively assess the adhesion strength of the different NHV-SPRG composite waterproofing products existing in the market, and the underlying concrete surface with the general rigid adhesion method. Due to the adhesion mechanism of the existing hard adhesive waterproof layer and the non-hardening soft adhesive layer interface being different, a new evaluation index, method, and criteria should be defined differently. Therefore, a new evaluation method and performance standard specifically designed for NHV-SPRG type of viscoelastic waterproofing materials are required.