本文關鍵詞： 預應力混凝土連續(xù)剛構 箱梁 裂縫抑制 混凝土組成 養(yǎng)護方法　出處：《重慶交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：近年來，由于大跨徑預應力混凝土連續(xù)剛構箱梁本身的優(yōu)越性，已被廣泛應用在橋梁建設中，特別是在山區(qū)高速公路建設中。但是，由于箱梁截面尺寸較大，混凝土澆筑后水泥水化產(chǎn)生大量的熱，再加上混凝土脫模后，由于工作面的限制使得混凝土箱梁腹板及底板的養(yǎng)護困難，以及施工現(xiàn)場環(huán)境因素的影響，使得混凝土箱梁產(chǎn)生大量裂縫。同時，由于對混凝土工作性能的要求，，現(xiàn)代混凝土的組成發(fā)生了很大變化，為達到我們的預期目的，我們必須采取必要的混凝土早期養(yǎng)護方法來抑制混凝土早期裂縫的產(chǎn)生，從而提高橋梁的使用壽命。 本論文結合重慶市交通科學技術項目《大跨徑預應力連續(xù)剛構橋梁懸臂施工過程節(jié)段養(yǎng)護工藝研究》，研究了混凝土組成及養(yǎng)護條件對混凝土早期性能的影響，意識到混凝土早期養(yǎng)護的必要性，并總結出一套適合大跨徑預應力混凝土連續(xù)剛構箱梁懸臂節(jié)段澆筑混凝土的早期養(yǎng)護方法，即模貼+自動噴霧養(yǎng)護，以解決大跨徑預應力混凝土連續(xù)剛構箱梁懸臂節(jié)段澆筑混凝土早期養(yǎng)護困難及早期裂縫的問題。主要研究內容包括以下方面： ①在闡述了本課題的研究背景、內容、意義的基礎上，對混凝土的早期收縮與開裂的研究現(xiàn)狀、連續(xù)剛構箱梁懸臂節(jié)段澆筑混凝土早期養(yǎng)護方法及存在的問題進行了研究。 ②在比較了過去混凝土與現(xiàn)代混凝土的區(qū)別的基礎上，研究了連續(xù)剛構箱梁懸臂施工及結構特點對混凝土的性能要求以及水泥、摻合料、減水劑、養(yǎng)護方式對混凝土早期性能的影響，并提出現(xiàn)代混凝土的早期性能特點以及早期養(yǎng)護的必要性。 ③總結了一套適合大跨徑預應力混凝土連續(xù)剛構箱梁懸臂節(jié)段澆筑混凝土早期養(yǎng)護的方法即模貼+自動噴霧養(yǎng)護，并結合依托工程對該養(yǎng)護方法的效果進行了試驗。
[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.
【學位授予單位】：重慶交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U445.7

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