【摘要】：研究表明,混凝土面板堆石壩面板混凝土的強(qiáng)度特性受到許多因素的影響,其中碳化和硫酸鹽侵蝕為兩個(gè)主要因素。但工程界目前對(duì)于面板混凝土的強(qiáng)度特性研究,仍大多局限于單一因素的影響研究,即使考慮二者的共同作用,也僅按照已有經(jīng)驗(yàn)粗略判斷兩者對(duì)強(qiáng)度特性的復(fù)合影響,而理論依據(jù)卻明顯不足。因此,在考慮碳化與硫酸鹽侵蝕共同作用的基礎(chǔ)上,深入開展面板混凝土強(qiáng)度特性及其演變規(guī)律的研究仍是十分必要的。本文首先對(duì)面板混凝土的硫酸鹽侵蝕機(jī)理及碳化機(jī)理進(jìn)行了系統(tǒng)分析;然后,分別通過硫酸鹽干濕循環(huán)試驗(yàn)、碳化試驗(yàn)以及碳化與硫酸鹽干濕循環(huán)的交替試驗(yàn),分析其對(duì)面板混凝土強(qiáng)度特性的影響機(jī)理。研究結(jié)果表明:(1)水灰比和侵蝕液濃度是面板混凝土抗硫酸鹽侵蝕的主要影響方面。水灰比越小,硫酸鹽侵蝕后面板混凝土的抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度減少幅度越小;侵蝕液濃度越小,硫酸鹽侵蝕后面板混凝土的抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度減少幅度越小。(2)水灰比與面板混凝土的碳化深度關(guān)系密切,水灰比越大,面板混凝土碳化深度越大。隨著碳化齡期的延長(zhǎng),面板混凝土碳化深度也逐漸增加。在碳化齡期相同的條件下,碳化深度越大,后續(xù)碳化深度的增幅越大。(3)隨著碳化時(shí)間的延長(zhǎng),面板混凝土的抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度也越來越大。水灰比越大,碳化后面板混凝土抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度增加幅度越大。隨著碳化時(shí)間的延長(zhǎng),面板混凝土抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度的增加呈現(xiàn)先快后慢的趨勢(shì)。(4)在碳化與硫酸鹽侵蝕交替作用下,水灰比越小,面板混凝土在交替循環(huán)下的抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度下降幅度越小;侵蝕液濃度越小,面板混凝土在交替循環(huán)下的抗壓強(qiáng)度與其劈裂抗拉強(qiáng)度下降幅度越小。(5)在碳化與硫酸鹽侵蝕共同作用下,二者對(duì)面板混凝土強(qiáng)度的影響特征并非各自影響效應(yīng)的簡(jiǎn)單疊加,而呈現(xiàn)出交替影響、互為激化的影響規(guī)律。
[Abstract]:The results show that the strength characteristics of concrete face slab of concrete face rockfill dam are affected by many factors, among which carbonation and sulfate erosion are two main factors. However, at present, most of the researches on the strength characteristics of slab concrete are still confined to the influence of a single factor. Even if the interaction between the two is considered, the composite effect of the two factors on the strength characteristics can only be roughly judged according to the existing experience. But the theoretical basis is obviously insufficient. Therefore, on the basis of considering the interaction of carbonation and sulfate erosion, it is necessary to deeply study the strength characteristics and evolution law of concrete faced with concrete. In this paper, the mechanism of sulfate erosion and carbonation of concrete face concrete is analyzed systematically. Then, the influence mechanism of sulphate dry and wet cycle test, carbonation test and alternative carbonation and sulphate wet cycle test on the strength characteristics of concrete face concrete was analyzed. The results show that: (1) the water-cement ratio and the concentration of erosive fluid are the main factors affecting the sulfate resistance of concrete face. The smaller the water-cement ratio, the smaller the reduction range of compressive strength and splitting tensile strength of face concrete after sulfate erosion. The smaller the concentration of erosion solution, the smaller the reduction of compressive strength and splitting tensile strength of face concrete after sulphate erosion. (2) the ratio of water to cement is closely related to the carbonation depth of face concrete, and the ratio of water to cement is larger. The greater the carbonation depth of concrete face concrete. With the prolongation of carbonation age, the carbonation depth of concrete face concrete increases gradually. Under the same carbonation age, the greater the carbonation depth, the greater the subsequent carbonization depth. (3) with the prolongation of carbonation time, the compressive strength and the splitting tensile strength of concrete face are also increasing. The higher the water-cement ratio, the greater the increase of compressive strength and splitting tensile strength of carbonized concrete face concrete. With the prolongation of carbonation time, the increase of compressive strength and splitting tensile strength of concrete face concrete shows a tendency of first fast and then slow. (4) under the alternating action of carbonation and sulfate erosion, the ratio of water to cement decreases. The decrease of compressive strength and splitting tensile strength of slab concrete under alternating cycle is smaller. The smaller the concentration of corrosion solution, the smaller the decrease of compressive strength and splitting tensile strength of concrete face concrete under alternating cycle. (5) under the combined action of carbonization and sulfate erosion, The influence characteristics of the two factors on the strength of concrete face slab are not the simple superposition of the effect of each other, but the law of alternating influence and mutual aggravation.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TV431

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