Effects of nano-SiO2 with modified surface on properties of#br#
recycled asphalt binder
Gao Jiyang1,2 Zeng Menglan1 Sun Zhilin3
1. Hunan University, Changsha 410000, China; 2. Bureau of Management Public Road in Hunan Province, Changsha 410000, China;
3. Changsha University of Science and Technology, Changsha 410000, China
Abstract：In order to improve recycling capability of recycled asphalt, RA-F0110 recycling agents and OP-900 recycling agents are selected as A and B recycling agents for old asphalt, respectively; silance coupling agents KH-550 and KH-570 are used for surface modification of the nano-SiO2; the preparation method of nano-recycling asphalt was determined by comparing the performance graded HT of nano-recycling asphalt under different rates, different stirring time and different standing time; based on the performance graded tests with different kinds and different mixing amount of recycling agents, the kind of recycling agents and the mixing amount of recycling agents were determined; in the performance graded tests of DSR & BBR, the additive amount of nanophase materials was determined. The test results show that: after the surface modification of nano-SiO2, the occurrence of agglomeration is reduced. Because the nano-SiO2 particles were wrapped, so that the increased size of nano-SiO2 may lead to the obvious decrease of the specific surface area of individual particles, and the nano-SiO2 can be more stable in the asphalt. The improvement effect of KH-550 surface modifier shall be better than that of KH-570. The regeneration effects of the recycling agent A are better than those of the recycling agent B. With the same mixing amount of recycling agents, the recycling asphalt mixed with a certain proportion of nano-SiO2 can receive wider service temperature ranges with continous grading. When the mixing amount of nano-SiO2 is 5% and the amount of the recycling asphalt A is 15%, the optimal performance indexes can be attained for the nano-recycling asphalt.
