Effective approaches are required to be developed to solve the poor compatibility and thermal stability problems of crumb rubber-modified asphalt (CRMA). This study focuses on a method called microwave activation. However, seldom researches pay attention to the properties of MACRMA after aging. The objective of this study was to prepare microwave-activated CRMA (MACRMA) and investigate the performance of asphalt after aging. The samples were subjected to thin-film oven test (TFOT) at different times and temperatures. The effect of heat aging on the properties of MACRMA was evaluated by three indicator tests: viscosity, dynamic shear rheology test (DSR), and repeat creep recovery test (RCRT). The test results indicated that the MACRMA after two aging conditions had noticeably lower performance values (e.g., penetration, ductility) compared to unaged samples, and thus, the need to control temperature and time for mixing and construction was verified to be important. In addition, the G*/sin δ and phase angle values were largely influenced by the TFOT aging temperature and time. The MACRMA’s ability to recover was improved after aging. Compared with the aging temperature, the aging time had a more significant effect on the deformation and recovery ability of MACRMA.
To reveal the mechanical characteristics of BRT asphalt pavement structures under the combined effects of the temperature field and load of buses, a series of finite element analysis models were established in the software application ABAQUS to simulate the Lanzhou BRT asphalt pavement project. The actual BRT road temperature field in summer and loads of buses at different speeds were introduced in the model with user subroutines before conducting a sequentially coupled thermal-mechanical analysis. The results indicated that the BRT asphalt pavement structure readily experienced permanent deformation, mainly comprising unstable rutting during the high-temperature season, and the possibility of cracking was higher for the subbase bottom than for the base. Temperature imposed a greater influence than BRT vehicle frequency. To delay fatigue cracking of the base and subbase and the shear failure of asphalt pavement structures, BRT operating speed should be controlled within 30–40 km/h. In actual BRT asphalt pavement engineering, special attention should be given to the deformation resistance of the intermediate surface layer.
This paper adopted the mixing modification to prepare MAH-POE/ LMW-EP/PP/CaCO3 thermoplastic composites, probed into the structure of composites, the system compared the modification made by composites and the single system of the rheological property, the influence law of flow rate, mechanical properties, dynamic mechanical thermal analysis (DMTA) and the network structure of the composite material etc. The results showed that the elastomer was preferably dispersed in the PP, the two phases have a strong interaction force, When the content reaches 20%, the tensile strength decreased by 7.37%, the elongation at break increased by 410.1%, the impact strength reached 546.3J.m2, there has been broad and strong low internal friction peak tanδ2 peak, and with the increase of elastomer content, liquidity blends decreases, MFR decreases. In short, quadruple composites have optimum overall performance. Polypropylene (PP) is a source of abundant, excellent mechanical properties, good electrical insulation, and resistance to stress cracking and has good overall performance excellent chemical stability thermoplastics. Widely used in medical equipment, auto parts , building materials, home office supplies, as well as a large number of transport and packaging materials [1-3] . However, due to the strong ability of PP crystallization, resulting PP mold shrinkage, impact toughness is poor [4-5] , in order to solve this problem , the current modification methods often used are: copolymerization and blending modification , and blending is the most simple and effective toughening PP method . The main focus ① blended with a modified rubber or thermoplastic elastomer blends toughening ; ② Toughening with other organic polymers ; ③ rigid inorganic particle toughening ; ④ elastomer / toughening common inorganic particles [6-10] . POE because both thermoplastic plastics , but also the crosslinkable rubber , which has a small cohesive energy , high shear sensitivity , and good compatibility with PP machining , toughening modification of PP the effect is significant and widespread attention , but the larger POE elastomer modified PP viscosity , processing performance be affected [11-13] . In this paper, LMW-EP and MAH-POE-modified PP, while adding CaCO3 prepared by a four-element composite elastomer material, by contrast, explores the compatibility of the quaternary blends, processing fluidity and mechanical properties
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