The Modification Of Silicate Mineral Powders And The Application Performance In Bitumen

Silicate mineral powder is a kind of nonmetal inorganic mineral filler, which is now mainly used in rubber, architectural coatings, plastics, paper, bitumen and other fields. The silicate mineral powder could improve the bitumen aggregate ratio, and enhance the waterproof performance of bitumen pavement. Because the silicate mineral powder is hydrophilic nonmetal mineral filler, differences exist in the interface between bitumen and bitumen. The differences result in poor compatibility, which make it difficult to disperse uniformly in bitumen. Therefore, surface modification of the silicate mineral powder is necessary. Improving the powder surface’s physicochemical properties, compatibility and dispersion, which could raise the bitumen’s comprehensive performance.The structure and surface characteristics of mineral analysis Firstly, a kind of silicate mineral powder was selected, which was in common use. By means of XRD, IR, XPS, whiteness instrument, the performance of chemical composition, surface chemical bond could be reached. Taking advantage of these features, the experiment of raw powder’s modification and theory analysis could be done.Test showed that the powder is a kind of shelf-like silicates.The choice of surface modifier.The raw powder modification was by drying process, modifier agent: KH-560, KH-570. octyltriethoxysilane and propyltriethoxysilane. Using absorbency and contact angle method for pre-evaluation, the best type modifier agent was selected.The contact angle of linear propyl and octyl reached 110 ° and 115 respectively.The surface structure change before and after modification coould be measured by Infrared spectroscopy, Raman spectroscopy. Besides, modification mechanism and effect could finally be determined.Surface functionalization process of formulation development.Then, by controlling variables method, using heating modification and direct spray modification process, determine the every kind of method of the best modification process, including coupling agent hydrolysis time, temperature, modification time, dispersing agent and other parameters. According to experiment, the optimum modification method and process could be obtained. Modified time was greatly reduced by heating, but required a lot of water and ethanol, as well as large-scale special equipment. Therefore, considering modifying effect and economic factors,directly sprayed modification process was chosen.Finally, the powder was added into bitumen, making a specimen. The stability of the specimens was tested by freeze-thaw splitting test and the anti-temperature performance was tested by the rutting test. Freeze-thaw splitting strength ratio raised from 61% to 84%, TSR value greater than standard. Freeze stable modified specimen raised from 4846 times/mm to 6300 times/mm, greater than the regulatory requirements of 3000 times/mm,The evaluation of powder modification effect was related to the results of bitumen application.