大跨径预应力混凝土连续刚构箱梁悬臂节段浇筑混凝土早期养护方法研究

发布时间：2018-02-25 10:21

本文关键词： 预应力混凝土连续刚构箱梁裂缝抑制混凝土组成养护方法　出处：《重庆交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来，由于大跨径预应力混凝土连续刚构箱梁本身的优越性，已被广泛应用在桥梁建设中，特别是在山区高速公路建设中。但是，由于箱梁截面尺寸较大，混凝土浇筑后水泥水化产生大量的热，再加上混凝土脱模后，由于工作面的限制使得混凝土箱梁腹板及底板的养护困难，以及施工现场环境因素的影响，使得混凝土箱梁产生大量裂缝。同时，由于对混凝土工作性能的要求，，现代混凝土的组成发生了很大变化，为达到我们的预期目的，我们必须采取必要的混凝土早期养护方法来抑制混凝土早期裂缝的产生，从而提高桥梁的使用寿命。本论文结合重庆市交通科学技术项目《大跨径预应力连续刚构桥梁悬臂施工过程节段养护工艺研究》，研究了混凝土组成及养护条件对混凝土早期性能的影响，意识到混凝土早期养护的必要性，并总结出一套适合大跨径预应力混凝土连续刚构箱梁悬臂节段浇筑混凝土的早期养护方法，即模贴+自动喷雾养护，以解决大跨径预应力混凝土连续刚构箱梁悬臂节段浇筑混凝土早期养护困难及早期裂缝的问题。主要研究内容包括以下方面： ①在阐述了本课题的研究背景、内容、意义的基础上，对混凝土的早期收缩与开裂的研究现状、连续刚构箱梁悬臂节段浇筑混凝土早期养护方法及存在的问题进行了研究。 ②在比较了过去混凝土与现代混凝土的区别的基础上，研究了连续刚构箱梁悬臂施工及结构特点对混凝土的性能要求以及水泥、掺合料、减水剂、养护方式对混凝土早期性能的影响，并提出现代混凝土的早期性能特点以及早期养护的必要性。 ③总结了一套适合大跨径预应力混凝土连续刚构箱梁悬臂节段浇筑混凝土早期养护的方法即模贴+自动喷雾养护，并结合依托工程对该养护方法的效果进行了试验。
[Abstract]:In recent years, because of the superiority of long-span prestressed concrete continuous rigid frame box girder, it has been widely used in bridge construction, especially in mountain highway construction. After the concrete is poured, the cement hydration produces a lot of heat, and after the concrete demoulding, because of the restriction of the working face, the maintenance of the concrete box girder web and bottom slab is difficult, as well as the influence of the environmental factors on the construction site. Make concrete box girder produce a lot of cracks. At the same time, because of the requirement of concrete working performance, the composition of modern concrete has changed greatly, in order to achieve our expected purpose, In order to improve the service life of bridges, we must adopt the necessary early curing methods of concrete to restrain the early cracks of concrete. In this paper, the influence of concrete composition and maintenance conditions on the early performance of concrete is studied in the light of Chongqing Traffic Science and Technology Project "long span prestressed continuous rigid frame bridge cantilever maintenance technology". Conscious of the necessity of early curing of concrete and summing up a set of early curing methods suitable for long span prestressed concrete continuous rigid frame box girder cantilever section pouring concrete, that is, automatic spray curing with mould paste, In order to solve the problem of early maintenance and early crack of cantilever section of long-span prestressed concrete continuous rigid frame box girder, the main research contents include the following aspects:. 1. Based on the research background, content and significance of this subject, the present situation of early shrinkage and cracking of concrete, the early curing methods of cantilever section of continuous rigid frame box girder and the existing problems are studied. 2 on the basis of comparing the difference between the former concrete and the modern concrete, the performance requirements of the cantilever construction and the structural characteristics of the continuous rigid frame box girder, as well as the cement, admixture, water reducing agent, are studied. The influence of curing mode on the early performance of concrete is discussed, and the characteristics of early curing of modern concrete and the necessity of early curing are put forward. This paper summarizes a set of early curing methods for cantilever section concrete of long-span prestressed concrete continuous rigid frame box girder, I. e., automatic spray curing of formwork, and tests the effect of this method in combination with supporting engineering.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.7

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