本文選題：海洋環(huán)境 + 高性能混凝土　； 參考：《南京航空航天大學(xué)》2014年碩士論文

【摘要】：海洋環(huán)境中因氯離子擴(kuò)散造成混凝土結(jié)構(gòu)的破壞己經(jīng)成為全球土木工程界普遍關(guān)注的耐久性災(zāi)害。對于后張法預(yù)應(yīng)力混凝土箱梁(簡稱預(yù)應(yīng)力混凝土箱梁),由于長期受到海洋鹽霧等侵蝕作用,大量氯離子侵入混凝土中,致使箱梁中的鋼筋嚴(yán)重銹蝕,從而混凝土箱梁難以達(dá)到100年的設(shè)計(jì)壽命要求。本文分別對混凝土箱梁懸臂板、斜腹板以及底板鋼筋達(dá)到5%和10%起銹概率時(shí)的服役壽命進(jìn)行了預(yù)測,并提出了能夠延緩鋼筋起銹時(shí)間的一系列措施,從而提高箱梁耐久性、保證結(jié)構(gòu)能滿足100年的服役要求。本文主要得出以下結(jié)論:(1)為了研究不同摻量礦物摻合料混凝土的耐久性能,試驗(yàn)采用4組不同配合比的高性能混凝土。礦物摻合料等量替代水泥,F0、F20分別表示粉煤灰摻量為0和20%的C60普通混凝土和C60高性能混凝土,S30表示表示礦渣摻量為30%的C80高性能混凝土,S60分別表示礦渣摻量為60%的C50高性能混凝土;(2)海洋大氣環(huán)境下,預(yù)應(yīng)力混凝土箱梁的耐久性主要取決于懸臂板與斜腹板以及箱梁底板鋼筋的起銹時(shí)間。預(yù)應(yīng)力筋在長達(dá)100年的服役過程中,因波紋管的保護(hù)作用與其保護(hù)層厚度較大,不可能發(fā)生因氯離子擴(kuò)散滲透導(dǎo)致的鋼筋銹蝕作用;(3)海洋大氣環(huán)境下預(yù)應(yīng)力混凝土箱梁,若不采取防腐措施,則懸臂板與斜腹板在5年之內(nèi)就會發(fā)生銹蝕,箱梁底板主筋的銹蝕時(shí)間相對較長。對于F0、F20、S30及S60高性能混凝土,防銹效果依次增強(qiáng),其中F0與F20效果差別不明顯,S30與S60底板的服役壽命均可達(dá)到50年;(4)海洋大氣環(huán)境下預(yù)應(yīng)力混凝土箱梁,若在懸臂板與斜腹板涂刷浸漬深度不小于8mm的硅烷,并在箱梁底板涂刷浸漬深度約0.5~2mm的硅烷,則箱梁可以達(dá)到100年、甚至120年的設(shè)計(jì)壽命要求,其中,采用S60高性能混凝土效果最好;(5)為滿足海洋大氣環(huán)境下長壽命預(yù)應(yīng)力混凝土箱梁的耐久性要求,需選用高性能混凝土,并施加一定的附加防護(hù)措施,如:適當(dāng)增加保護(hù)層厚度,選用不銹鋼鋼筋,在箱梁表面涂刷硅烷,在配制混凝土過程中摻入阻銹劑等;(6)若預(yù)應(yīng)力混凝土箱梁底板的第一排主筋采用不銹鋼鋼筋,混凝土材料選用F20、S30或S60高性能混凝土并摻加一定量的阻銹劑,在懸臂板與腹板表面涂刷滲透深度不小于8mm的硅烷,則海洋大氣環(huán)境下預(yù)應(yīng)力混凝土箱梁的壽命有可能達(dá)到500年。
[Abstract]:The damage of concrete structures caused by chloride ion diffusion in marine environment has become a global civil engineering field of universal concern for durability disasters. For the post Zhang Fa prestressed concrete box girder, due to long term erosion of sea salt mist, a large amount of chloride ions intrude into concrete, resulting in serious corrosion of steel bars in box girder. Therefore, the concrete box girder is difficult to meet the design life requirement of 100 years. In this paper, the service life of cantilever slab, inclined web plate and bottom steel bar of concrete box girder is predicted when the probability of rusting is 5% and 10% respectively, and a series of measures are put forward to delay the rusting time of steel bar, so as to improve the durability of box girder. Ensure that the structure meets 100 years of service requirements. In order to study the durability of concrete with different contents of mineral admixtures, four groups of high performance concrete with different mix ratio are used in the experiment. Mineral admixture is used to replace cement F0 / F20 for ordinary concrete with fly ash content of 0 and 20% and C60 high performance concrete for C60 high performance concrete with 30% slag respectively. S60 indicates slag content is 60%, respectively. In the marine atmosphere, The durability of prestressed concrete box girder mainly depends on the rusting time of cantilever slab, inclined web plate and steel bar on box girder floor. In the course of 100 years of service of prestressed tendons, because the protective effect of bellows and the thickness of protective layer are great, it is impossible to take place in the prestressed concrete box girder caused by chloride ion diffusion permeation. If the anticorrosive measures are not taken, the corrosion of the cantilever plate and the inclined web will occur within 5 years, and the corrosion time of the main reinforcement on the bottom plate of the box girder is relatively long. For F0 / F20 / S30 and S60 high performance concrete, the antirust effect is enhanced in turn, and the service life of S30 and S60 bottom slabs can reach 50 years or 4) under marine atmosphere, and the difference between F0 and F20 is not obvious. If silane with a depth of not less than 8mm is applied on the cantilever and inclined web, and silane with a depth of about 0.5~2mm on the bottom of the box girder, the box girder can meet the design life requirement of 100 years or even 120 years. In order to meet the durability requirements of long-life prestressed concrete box girder in marine atmosphere, high performance concrete should be selected and some additional protective measures should be applied, such as increasing the thickness of protective layer appropriately. Stainless steel bars are selected, silane is applied on the surface of box girders, rust inhibitor is added in the process of making concrete, etc.) if the first row of main bars of prestressed concrete box girders is made of stainless steel bars, If F20 S30 or S60 high performance concrete is used as concrete material and a certain amount of rust inhibitor is added, silane whose penetration depth is not less than 8mm on the surface of cantilever slab and web plate, the life of prestressed concrete box girder can reach 500 years in marine atmosphere.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U448.35
，

本文編號：1968150