# Experimental Study of Low Temperature Performance of Porous Asphalt Mixture
###### Abstract  
Porous asphalt mixture can be used as a road surface paving material with the remarkable advantage to prevent water accumulation and ponding. However, the performance of porous asphalt mixture in low temperature environment has not been thoroughly investigated, and this forms the subject of research in the present study. The mineral aggregate gradation of porous asphalt mixture was designed based on Bailey method, and the low temperature performance of porous asphalt mixture was studied by means of the low temperature bending test. The factors affecting the low temperature performance of porous asphalt mixture were analyzed through the orthogonal experimental design method, and the effects of porosity, modifier content, aging condition, and test temperature on the low temperature performance of porous asphalt mixture were evaluated. The results showed that the modifier content was the most important factor affecting the low temperature performance of porous asphalt mixture, followed by the test temperature, while the porosity and the aging condition were the least. Among the three performance evaluation indicators, namely the flexural tensile strength, maximum bending strain, and bending stiffness modulus, the maximum bending strain had the highest sensitivity to the porosity. It can be seen from the single factor influence test of porosity that there existed an approximately linear relationship between the maximum bending strain and the porosity of porous asphalt mixture, and the maximum bending strain decreased with increasing porosity. Furthermore, in order to ensure the good working performance of porous asphalt mixture in low temperature environment, the porosity should also satisfy the required limits of the maximum bending strain. p 2021 28  
along the edge of the pavement [2]. Moreover, due to the macro-texture of the surface, a higher skid resistance can be obtained for porous asphalt mixture when compared to other surface layer materials [3]. Therefore, the use of porous asphalt pavement is a method to effectively prevent the accumulation and ponding of water on road surface [4; 5], which has been conceived and adopted in numerous countries including France, Germany, Spain, United Kingdom, New Zealand, Japan and the United States [6; 7; 8; 9; 10; 11; 12]. Porous asphalt is a composite material comprising of mineral materials, binders and additives. From pavement engineering viewpoint, the selection of raw materials is the key to determine the pavement properties of porous asphalt mixture [13; 14]. In the process of mix proportioning, the identification of design objectives is of prime importance [15]. To determine the best combination of aggregate and binder so as to achieve good overall performance of the asphalt pavement, the mix proportion design of asphalt mixture must be engineered, which includes the identification of design objectives, the control of gradation and the determination of binder content [16; 17]. Adjusting the design goals according to the application requirements is the prerequisite for ensuring the durability and economy of the pavement structure. Due to the diversity of design goals, there is no established universal specification for the mix proportion design, and different design methods for porous asphalt mixtures have been proposed for different design goals. Currently, many researchers have studied the mix proportion design of porous asphalt. [PERSON] [18] and [PERSON] [19] studied the relationship between porosity and passing rates of series of sieve apertures through laboratory tests, and improved the mix proportions design method of porous asphalt. [PERSON] [20] applied the Bailey method to the mix proportion design of porous asphalt, and proposed the concept of \"reserved porosity\" to determine the target porosity. [PERSON] et al.