# Properties and Preparation of a New High-Permeability Emulsified Asphalt and Its Modification
###### Abstract  
Emulsified asphalt is widely used as a prime coat in road engineering, especially in pavements with cement-stabilized semi-rigid bases. The objective of this paper is to develop a new emulsified asphalt with high permeability and pulling-off strength. A new type of high-permeability emulsified asphalt was prepared by using 55.2% diluted asphalt (44.16% matrix asphalt + 11.04% diluent) + 40% emulsion (2% emulsifier + 0.5% stabilizer + 1% osmotic agent + 1% op-10 + 35.5% water) + 4.8% aromatic oil. The storage stability was verified to be better, and the penetrating rate and depth were increased largely compared to the traditional products. To improve pulling-off strength, the high-permeability emulsified asphalt was further modified by mixing with 20% water-based epoxy resin and a curing agent. The penetration, pull-off, and shear strength tests were also conducted. It can be found that the permeability, adhesive, and water-resisting properties of the modified high-permeability emulsified asphalt can be further improved to a certain degree. high permeability; modified; emulsified asphalt; prime coat +
Footnote †: journal: Applied Sciences  
stability [6]. It still has excellent adhesion under the action of immersion, ensuring the adhesion of the base course and surface course, so it is used more and more widely [7; 8]. However, the penetration of ordinary cationic emulsified asphalt could be poor. Anionic emulsified asphalt can be penetrated into the semi-rigid base [9] but it often appears as a sticky skin in the actual construction and is easily carried by the construction machinery [10]. At present, prime coat asphalt is normally required as high-permeability emulsified asphalt in China. If the emulsified asphalt is modified, it can be a good solution to the disadvantages of poor permeability [11]. The development of emulsified asphalt began in the early 20 th century. Emulsified asphalt was used for spraying to reduce dust. It was first applied in road construction in the 1920s [12]. Since the 1980s, some researchers have added anionic emulsifiers into the asphalt. In order to prepare prime coat emulsified asphalt, a certain proportion of mineral oil was also added [13]. At the beginning of the 21 st century, the federal lands highway issued an investigation report called \"guidelines for using prime and tack coats\" which carried out an in-depth investigation and summary of the use of materials, methods, functions, and other aspects of the prime coat [14]. [PERSON] added waste tire thermal asphalt in the matrix asphalt. A rubber emulsified asphalt with high adhesion and permeability was prepared [15]. [PERSON] and [PERSON] used the concept of \"selective permeability\", and developed high permeability and high-permeability materials [16]. [PERSON] et al. used environmentally friendly penetrants, compound modifiers, and other materials to improve the permeability and adhesion of emulsified asphalt and studied the construction and production control technology of high-permeability emulsified asphalt [17]. [PERSON] et al. mixed a certain proportion of permeable solvent in asphalt to produce high-permeability emulsified asphalt [18]. The permeability on the semi-rigid base, the best amount of spraying time, and other factors were surveyed; it was concluded that the penetrating depth increased with the increase of spraying amount. Other factors such as temperature and the mixing ratio between emulsified asphalt and modifier have effects on the performance of the modified asphalt. Good high-temperature storage stability and suitable mixing ratios can help to prepare an effective modified emulsified asphalt [19]. Summarizing the research work and application of permeable materials, it was found that mixing diluted asphalt to emulsified asphalt was a new way to modify the emulsified asphalt [20]. Some experts and scholars had also studied emulsified asphalt that was used as a permeable material.