青海高原地区预制箱梁混凝土质量控制技术研究

发布时间：2018-06-05 01:10

本文选题：桥梁工程 + 预制箱梁　；参考：《长安大学》2015年硕士论文

【摘要】：青藏高原地区具有独特的气候环境特点,如海拔高、昼夜温差大、太阳辐射强、湿度小、风频风大、冻融循环恶劣等,这些因素必然会对混凝土的质量以及桥梁的施工带来一些不利的影响,如混凝土强度上升缓慢、冻融循环加剧、干燥收缩增大等,此外,高原地区的施工力量相对薄弱,施工技术较为落后,因此,如何提升高原地区桥梁混凝土结构的质量,提高混凝土结构的使用寿命显得尤为重要。预制箱梁由于其诸多的优点得到了广泛的应用,但由于高原地区独特的环境特征,箱梁混凝土容易出现外观质量不佳、强度不高、收缩大等工程质量问题,直接影响预制箱梁的质量。本文以青海地区箱梁混凝土为依托,对青海地区的环境气候进行调研,分析了青海地区特殊环境,如温度、温差、降水、大风等对混凝土结构的影响,总结了当地的混凝土在应用过程中存在的典型问题;采用高性能混凝土的配制原则,在考虑安全性、工作性和经济性的传统混凝土配合比设计方法的基础上,结合青海地区混凝土配合比设计过程中存在的典型问题,研究了水胶比、砂率、单位用水量以及粉煤灰掺量对箱梁C50混凝土性能(工作性能、力学性能、干燥收缩性能)的影响,提出了以耐久性为主的箱梁高性能混凝土配合比设计方法。结果表明,采用合适的砂率、单位用水量以及粉煤灰掺量,降低水胶比,对于混凝土性能的提升有着良好的效果;根据青海地区特点,提出了高原地区预制箱梁的施工工艺。研究成果为解决青海高原预制箱梁混凝土质量控制的工程技术问题提供了重要的技术支持。
[Abstract]:The Qinghai Tibet plateau area has unique climatic and environmental characteristics, such as high sea level, large day and night temperature difference, strong solar radiation, low humidity, large wind frequency wind and bad freezing and thawing cycle. These factors will inevitably bring some adverse effects on the quality of concrete and the construction of bridges, such as the slow rise in the strength of the concrete, the intensification of the freezing and thawing cycle and the increase of drying shrinkage. In addition, the construction strength of the plateau area is relatively weak and the construction technology is relatively backward. Therefore, it is very important to improve the quality of the concrete structure of the bridge in the plateau and improve the service life of the concrete structure. The precast box girder has been widely used because of its many advantages, but the unique environmental characteristics of the plateau area are due to its unique environmental characteristics. The box girder concrete easily appears the quality problems of poor appearance quality, low strength and large shrinkage, which directly affects the quality of the precast box girder. Based on the case of box girder concrete in Qinghai, this paper investigates the environmental climate in Qinghai area, and analyzes the special environment in Qinghai area, such as temperature, temperature difference, precipitation, wind and so on. The typical problems existing in the application process of local concrete are summarized, and on the basis of the traditional concrete mix design method considering safety, work and economy, based on the preparation principle of high performance concrete, the water glue is studied on the basis of the typical problems existing in the design process of concrete mix proportion in Qinghai area. Ratio, sand rate, unit water consumption and fly ash content on the performance of box girder C50 concrete (working performance, mechanical properties, drying shrinkage performance), and put forward the design method of high performance concrete mix ratio of box girder with durability. The results show that the suitable sand rate, unit water consumption and fly ash content are used to reduce the ratio of water to glue. The improvement of concrete performance has good effect. According to the characteristics of Qinghai area, the construction technology of precast box girder in plateau area is put forward. The research results provide important technical support for solving the engineering technical problems of concrete quality control of precast box girder in Qinghai plateau.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.47

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