Asphalt mixes are common paving materials for road surfaces, but due to the increasing complexity of the climatic environment and the traffic loads are subject to asphalt plaster cracks, rods and other types of street population [1]. Asphalt and asphalt mixtures also generate large amounts of toxic and dangerous gases during production and preparation, which affect both the environment and the workers off. [2]. For this reason, polyuretics mixes were gradually used in road construction. Polyurethan mixes are paving materials made of polyurethane as a binder [3]. This means that polyurethanes can be constructed due to the active chemical reaction properties of the polyurethane reaction materials at room temperature [4]. Polyurethanes can save a lot of energy compared to asphalt mixtures, for which heated production and construction processes are required. In addition, the production and paving processes of polyurethan mixes do not produce any harmful gases, which makes it an environmentally friendly paving material.
Polyurethane mixtures have significant advantages over asphalt mixtures with regard to the mechanical properties, high -temperature stability and fatigue resistance. Yang found that a polyurethane mix had more than the triple of the tensile strength of a asphalt mixture [5]. Zhong found that polyurethan mixtures were particularly good at high temperatures, with dynamic stability up to 12,000 times/mm, which was the 10 -fold of the specifications for asphalt mixtures [6]. Cong came to the conclusion that the fatigue life of porous polyurethan mixes was more than an order of magnitude than that of porous asphalt mixtures [7]. In addition, polyurethan mixes are superior to the asphalt mixtures in other lane performance features. Liao and Chen both found that polyurethanes had a better antiscid performance, durability and noise reduction than asphalt mixtures; However, the water stability of polyurethanes was relatively bad [8]Present [9]. Therefore, water stability is a lack of the road performance of the polyurethane mix.
The flood sensitivity of polyurethanes has been examined in detail. XU examined polyurethan mixes and found that the Marshall stability of the water immersion only 38 % rest was, and a freezer -tau cycle could reduce the gap resistance by up to 75 % [10]. The sun found that freezer -tau cycles and water diving could reduce the thickness of polyurethan mixes to 65.7 % or 68.4 % [11]. Cong took a loss of cantabrover as an indicator and found that most of the mass losses of water -soaked polyurethane mixtures exceeded over 20 %, while the asphalt mixtures were only about 10 % [12]. It can be seen that the deteriorating effect of water on the performance of the polyurethan mix is very significant and its water sensitivity is significantly higher than that of asphalt mixtures [13]Present [14].
Hong stated that due to the higher water sensitivity of polyurethan mixes on the mixed scale, the shape production method of the shape of the form could influence the water stability of the polyurethane mixtures [15]. In the interface scale, the water -induced acceptance of the Van der Waalspower, flastatures and hydrolysis led to reduced interface properties [16]. Guo came to the conclusion on the binder scale that the film thickness had a greater influence on the water stability and the resistance of polyurethanes mixtures [17]. However, most of the existing research remain at the level of the phenomenon description and the macroscopic performance breakdown. There is not only a lack of analysis of the deep deterioration mechanism of the water stability of polyurethanes mixes [18]Present [19]But there is also a lack of understanding of the synergistic deterioration of the scale. Therefore, the degradation mechanism of polyurethanes must be further examined under water environments.
In summary, it can be said that the effects of a water environment on the most important mechanical properties, volumetric properties and loss of abrasion are summarized in this article in order to describe the examination of the deterioration mechanism from water on polyurethanes mixes. On the interface scale of polyurethane aggregate, the influence law of a water environment was analyzed on the pulling and shear strength of the interface. In addition, the mechanism of the water environment on a polyurethane binder from the perspectives of microscopic morphology, water resistance, temperature sensitivity and the chemical structure were examined in the polyurethane scale. The research results offer important guidelines to improve the water stability of polyurethanes.