| Along with improvement of industry, progress of construction technology, development of theories of mathematics and mechanics, reform of computing technology and innovation of building materials, bridge construction has the tendency of long-span while meeting requirements for structure, function as well as economical and aesthetic unity. Mass concrete pouring including pile cap, cable tower and long-span pre-stressed concrete continuous bridge is a critical procedure in long-span bridge construction. For instance, dimensions of pile cap for pier 38# of Yellow River Bridge is 13.4×18.5×4.5m and one-time concrete pouring earthwork reaches 1115.6m3.While in construction, concrete structures always have cracks of different types and to different degree, which destroys their integrity and threatens safety of buildings. This is especially noticeable in cast-in-place mass concrete structures. Conditions for early temperature cracks in cast-in-place concrete structures is quite complicated and varied due to various factors including internal hydration heat, contraction and creep of concrete, construction technology as well as environmental temperature. At present, traditional construction control is mainly adopted in control of temperature cracks in mass concrete. No scheme of systematic and effective crack control is put forward from perspectives of materials, design and construction, based on laws of changes in temperature field , changes in temperature stress and laws of changes in cracks with changes of temperature in particular.Theories on crack-resistance design need to be improved as well. Pile cap, pier, cable tower and approach bridge of Jinan Yellow River Bridge are mass concrete structures which have inherent features of mass concrete. The conditions are quite complicated due to complex construction conditions, varied construction situations, great differences in raw materials of concrete. Besides, various issues are involved in internal concrete strength and temperature crack development, such as structure computation, construction design, material composition, physical-mechanical properties and construction technology. Taking cable tower, pier and long-span continuous bridge of the Bridge as research objects, the present researcher monitors internal real-time temperature of concrete in construction in order to get laws of changes in internal temperature and stress, put forward schemes of crack control and guarantee quality of site construction. Main research contents are as follows:(1)Measure temperatures of different parts inside the mass concrete with IntelliRock concrete maturity meter on site, which can not only monitor laws of changes in temperature field after pouring but also provide genuine and reliable evidence for construction of finite element model and prediction of cracks; monitor maturity of different parts and predict laws of changes in strength in different parts inside the mass concrete based on maturity theory, which guarantees quality of concrete and provide reliable site data for construction quality inspection.(2)Based on analysis of temperature control scheme and data on pier, cable tower and long-span continuous bridge of Jinan Yellow River Bridge, study the crack control measures from perspectives of raw materials, mix proportion, admixture, construction technology, etc.(3)Based on above analysis and research, put forward several suggestions, which may provide technological support for temperature crack control in future constructions.
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