The concrete transition zone plays an important role in bridge expansion joint structure, which provides a good connection between the expansion joint installation and bridge decks. However, the premature deteriorations of concrete transition zone are found to be the major diseases of expansion joint during service life. Therefore, a material with high ductility, superior durability, and low modulus/stiffness is highly desired for transition zone. Engineering cementitious composites (ECC), a kind of high-performance concrete featuring the prominent ductility and durability, are a promising material for transition zone of expansion joint. This paper introduces a specific ECC material for transition zone, which is modified by emulsified asphalt (EA-ECC), and has the high deformation ability and low modulus/stiffness. The flexural mechanical properties including flexural stress-load displacement relation, flexural secant stiffness, and elastic modulus of the EA-ECC’s matrix were investigated experimentally. The microstructures of EA-ECC were observed via scanning electron microscope (SEM) imaging. Additionally, the influence of test temperature on flexural mechanical properties of EA-ECC was also investigated. It is found that the ultimate flexural stress of EA-ECC reduces gradually with increasing EA content. Conversely, the flexural deformation capacity shows an increasing trend with EA content. Additionally, incorporating EA significantly reduces the flexural secant stiffness and elastic modulus of EA-ECCs. The research results concluded that incorporating EA in ECC can significantly improve the flexural deformation ability accompanied by relatively lower modulus, which is likely to reduce the impact load on transition zone caused by vehicle bumping and prolong the service life of the whole bridge expansion joint structure.
An ultra-thin layer wearing course with thickness between 15mm and 30mm are developed and applied for maintenance of asphalt pavement. The maximum size of the coarse aggregate is 10 mm. In this study, the high viscosity modified bitumen is used as binder for improving the anti-rutting and raveling performance of a porous mixture. Mixture designed study is carried out by combing the functional and structural performance measurements. The target air voids contents for those ultra-thin surfaces are between 15% and 20%. Important factors presenting the high temperature property, moisture feature, low temperature feature and anti-raveling performance are investigated in lab. Meanwhile, surface characteristic which reflect the sound absorption is also observed. A feasibility of using the ultra-thin wearing course mixture in China is proved. Trial sections are constructed in southeast part of China for studying the performance of ultra-thin waring course in maintenance engineering. The achievements from the study will provide technical support for the maintenance of asphalt pavement with moderate surface damage. It will also improve the skid resistance and the noise reducing function of the old pavement, which presents superior social and environmental benefits.
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