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The accumulation and incineration of waste tires have caused great damage to the environment. Therefore, recycling waste tires efficiently and economically has become an important issue in protecting world resources and the environment. In this study, 5%, 10%, and 15% rubber particles were used to replace fine sand in concrete, and basalt fibers (0.1%, 0.2%, and 0.3%) and polypropylene fibers (0.1%, 0.15%, and 0.2%) were added to rubber concrete to prepare hybrid fiber rubber concrete (HFRC). The experiments investigated the changes of mechanical properties of basalt (BF), polypropylene (PPF) fibers, and rubber particles when they were blended into concrete respectively, and the degree of influence of each factor on the mechanical and carbonation resistance of HFRC was investigated based on the orthogonal test. The results show that the rubber concrete’s mechanical and carbonation properties are improved to varying degrees after adding hybrid fibers. When the basalt fiber content is 0.2% and the polypropylene fiber content is 0.15%, the overall mechanical properties of HFRC reach the best state. When the basalt fiber content is 0.2%, the polypropylene fiber content is 0.15%, and the rubber content is 5%, the carbonation resistance of HFRC is the most ideal. In addition, the microstructure of HFRC was observed by scanning electron microscope.

In order to study the axial compression behavior of rectangular concrete short columns that have been strengthened with basalt fiber-reinforced polymer sheets, the axial compression test were conducted on 15 groups specimens. The parameters are the cross aspect ratio and the number of basalt fiber-reinforced polymer layers. As the aspect ratio increases, the confined effect of basalt fiber-reinforced polymer decreases. The strength of one ply of basalt fiber-reinforced polymer decreases as the aspect ratio increases, the range is not very obvious, but the two ply of basalt fiber-reinforced polymer has the obvious decreasing tendency. With the increase in aspect ratio, the square and rectangular section columns of basalt fiber-reinforced polymer confined have a certain size effect. When the aspect ratio is 1.0, the values of fcc/fc0 by one ply of basalt fiber-reinforced polymer and two ply of basalt fiber-reinforced polymer are 1.14 and 1.50, respectively. And when the ratio is 2.0, the values of fcc/fc0 are 1.06 and 1.16. The confined effect is best when the aspect ratio is 1.0, while there is no significant effect with the ratio of 2.0. Results of the theoretical analysis compared with the experimental results show good agreement. [ABSTRACT FROM AUTHOR]

To research the dynamic analysis problem of vertical non -- uniform high -- rise structure and towering structure, flexural vibrations were taken as examples with the consideration of combined action of superstructure and foundation as well as the action of rotation. Then the non -- uniform continuous towering structure was simplified to segmented uniform continuous structure, and the partial differential equation was turned into the ordinary differential equation by utilizing the orthogonality of vibration mode. A model of vertical segmented uniform continuous structure was presented and applied to the establishment of dynamic equation. The method is applicable in the dynamic analysis of non -- uniform structure. [ABSTRACT FROM AUTHOR]