# Laboratory Evaluation of Eco-Friendly Pervious Concrete Pavement Material Containing Silica Fume
## 1 Introduction
[26] conducted the experiments on silica fume-modified concrete. The results indicated that the addition of silica fume increased the hydration degree of cement paste, improved the properties of interfacial transition zone between hardened paste and aggregate, and enhanced the compressive strength. In summary, the addition of silica fumes can significantly improve the compressive strength, erosion resistance, freeze-thaw resistance, impact resistance, etc. However, there are few studies on the application of silica fumes in pervious concrete. The effect of silica fumes on pervious concrete needs further research. [PERSON] et al. [27] studied the permeability of silica fume-modified porous limestone aggregate concrete. The silica fume content was selected as 5-20% of cement by weight. The test results showed that the addition of silica fumes had considerable effects on both water and rapid chloride permeability of concrete. [PERSON] and [PERSON] [28] conducted experiments to comprehensively investigate the hydrological, functional, and structural characteristics of pervious concrete with four proportions of silica fumes and three aggregate gradations. The results indicated that the compressive strength of pervious concrete was enhanced by the addition of silica fumes. [PERSON] et al. [29] investigated the porous silicate material derived from silica fume with X-ray diffraction. The microstructure of porous silicate material was analyzed and the preparation of it was studied. [PERSON]. [30] studied the effects of silica fume on the workability and compressive strength of pervious concrete. Silica fumes were used as the replacement of Portland cement with the content of 0-10%. The results indicated that, when the silica fume content was less than 5%, the mixtures had comparable or slightly improved workability compared to control groups, when the silica fume content was 7%, workability was decreased. The 28d compressive strength increased with the dosage of 3-5%, but decreased when the dosage reached 7%, which was different from other researches. [PERSON] et al. [31] investigated the compressive strength of silica fume-modified pervious concrete with three mix ratios. The test results indicated the compressive strength of the three mixtures increased by 86%, 52%, and 48%, respectively when 10% silica fumes were incorporated. Such a high improvement on compressive strength deserved further research to confirm. There are few studies concentrating on silica fume-modified pervious concrete. Existing research mainly focuses on the strength properties of silica fume-modified pervious concrete, and the conclusions obtained are quite different. Moreover, there is almost no research concentrating on its durability. Therefore, it is necessary to carry out research to investigate the mechanical properties and durability of silica fume-modified pervious concrete. Based on previous research conducted by our group [32; 33], in order to evaluate the improvement of silica fumes on pervious concrete, silica fume-modified pervious concrete was prepared with equivalent volume method, the porosity, permeability, strength, and freeze-thaw durability of silica fume-modified pervious concrete with different silica fume incorporation levels were studied. Due to the porous structure of pervious concrete, strength loss was adopted to assess the freeze-thaw resistance for pervious concrete. The findings of this study will aid in understanding the positive effect of silica fumes on the strength and freeze-thaw durability of pervious concrete, and would certainly help in the futuristic development of rational design and application pertaining to silica fume-modified pervious concrete pavements.