本文選題：大壩混凝土 + 傳統(tǒng)抗裂性能指標(biāo)��； 參考：《浙江工業(yè)大學(xué)》2014年碩士論文

【摘要】：大壩混凝土的抗裂性能一直是工程界十分關(guān)注的問題。避免產(chǎn)生和減少裂縫一直是大壩混凝土的重點(diǎn)和難點(diǎn),因此抗裂性能評價方法和評價指標(biāo)顯得尤為重要。當(dāng)前我國在涉及溫度應(yīng)力的抗裂性能研究中大多采用水泥水化熱、混凝土絕熱溫升、收縮變形測量等較為單一或圓環(huán)約束、平板約束等試件尺寸較小的方法,沒有綜合溫度履歷與約束程度條件的影響來評價混凝土的早期開裂,與混凝土的工程實際相差較大。因此需要探索出評價混凝土抗裂性能的新方法,可以為工程技術(shù)人員在選用混凝土材料時提供有用的信息,以有效地保證大壩在各種環(huán)境條件下滿足既定的服役要求。 本文以三種不同種類水泥(即中熱硅酸鹽水泥MH,普通低熱硅酸鹽水泥LHA和高含氧化鎂低熱硅酸鹽水泥LHB)為對象,通過對試驗室標(biāo)準(zhǔn)養(yǎng)護(hù)條件下試件的相關(guān)力學(xué)性能指標(biāo)的測定,得到極限拉伸值,拉壓比和彈強(qiáng)比這三個抗裂性能傳統(tǒng)評價指標(biāo),以此評價混凝土配合比之間的抗裂性能優(yōu)劣關(guān)系。并且根據(jù)評價結(jié)果對三大傳統(tǒng)評價指標(biāo)的吻合性進(jìn)行分析判斷。在此基礎(chǔ)上,利用溫度應(yīng)力試驗機(jī)(TSTM),對混凝土試件進(jìn)行單軸約束試驗,得到混凝土在不同溫度歷程下的實時參數(shù)以及抗裂性能指標(biāo)。根據(jù)TSTM試驗的相關(guān)評價體系對混凝土各配合比進(jìn)行抗裂性能評價。最后通過試驗結(jié)果將傳統(tǒng)抗裂性能評價方法和基于TSTM的抗裂性能評價方法進(jìn)行對比和優(yōu)劣分析。 研究結(jié)果表明：1、在兩種不同的評價體系中,0.4水膠比的抗裂性能都優(yōu)于0.5水膠比,氧化鎂的微膨脹性質(zhì)表現(xiàn)出對混凝土抗裂性能的有利影響2、在TSTM溫度履歷不同的情況下,三種膠凝材料(MH,LHA)和LHB)的抗裂性能優(yōu)劣順序會發(fā)生相應(yīng)變動,3、通過徐變分析,三種膠凝材料在溫升階段后的膨脹更有利與混凝土的抗裂性能。4、綜合兩種試驗方法和兩套抗裂性能評價指標(biāo),結(jié)果表明傳統(tǒng)抗裂性能評價方法并不能很好地體現(xiàn)出不同膠凝材料對抗裂性能的影響,也不能反映低熱水泥、微膨脹水泥在控制大壩混凝土早期裂縫方面的潛在優(yōu)勢,并且三種傳統(tǒng)評價指標(biāo)存在評價結(jié)果不一致的情況,用單一指標(biāo)來判斷某種大壩混凝土的抗裂性能的可信度不高。而利用加權(quán)統(tǒng)計,在相同條件下,將TSTM抗裂性能評價結(jié)果與綜合加權(quán)后的傳統(tǒng)抗裂性能評價結(jié)果進(jìn)行對比分析,結(jié)果表明兩者具有較好的相似度。但在評價指標(biāo)細(xì)節(jié)方面,TSTM包含了力學(xué),變形和熱學(xué)三方面的評價信息,從而使評價結(jié)果更為合理和全面。
[Abstract]:The crack resistance performance of the dam concrete has always been a very concern in the engineering field. Avoiding and reducing the cracks is always the key and difficult point of the concrete of the dam. Therefore, the evaluation method and the evaluation index of the crack resistance are particularly important. In the current research on the cracking resistance of the thermal stress in China, the cement hydration heat is mostly used. Adiabatic temperature rise, measurement of shrinkage deformation and so on are relatively single or ring constraint. The method of smaller size of plate constraints, such as flat plate constraints, does not evaluate the early cracking of concrete with the influence of comprehensive temperature and constraint conditions, which is quite different from the concrete engineering practice. Therefore, a new method for evaluating the crack resistance of concrete is needed. It is believed that engineers and technicians will provide useful information when selecting concrete materials to effectively ensure that the dam meets the established service requirements under various environmental conditions.
In this paper, three different kinds of cement (medium heat Portland cement MH, ordinary low hot Portland cement LHA and high Magnesium Oxide low heat Portland cement LHB) are taken as the object. By measuring the related mechanical properties of the test specimen under the standard curing condition of the test room, the limit tensile value, the tensile pressure ratio and the elastic strength ratio are obtained by the traditional evaluation. In order to evaluate the relationship between the anti cracking performance of the concrete mix ratio, and to analyze the anastomosis of the three traditional evaluation indexes according to the evaluation results, the temperature stress test machine (TSTM) is used to test the concrete specimens by single axis constraint on this basis, and the concrete in real time under different temperature processes is obtained. Parameters and anti cracking performance indexes. According to the relevant evaluation system of TSTM test, the anti cracking performance of concrete mixture ratio is evaluated. Finally, the traditional anti cracking performance evaluation method and the TSTM based anti cracking performance evaluation method are compared and analyzed.
The results show that: 1, in the two different evaluation systems, the cracking resistance of 0.4 water to glue ratio is superior to 0.5 water glue ratio, and the micro expansion property of Magnesium Oxide shows a favorable effect on the crack resistance of concrete 2. Under the different temperature of TSTM, the order of anti cracking performance of three kinds of cementitious materials (MH, LHA) and LHB will change correspondingly. 3, 3, through the creep analysis, the expansion of three kinds of cementitious materials after the temperature rise stage is more favorable to the cracking resistance of concrete.4, comprehensive two test methods and two sets of anti cracking performance evaluation indexes. The results show that the traditional anti cracking performance evaluation method can not reflect the effect of different cementitious materials on the cracking resistance and can not reflect the low resistance. The potential advantage of hot cement and micro expansive cement in controlling the early cracks in concrete of dam concrete, and the three traditional evaluation indexes are not consistent in the evaluation results. The reliability of the crack resistance of a certain dam concrete is not high with a single index. And the TSTM cracking performance evaluation is based on the same conditions. The results of the traditional anti cracking performance evaluation after the comprehensive weighting are compared and analyzed. The results show that they have good similarity. But in the detail of the evaluation index, TSTM contains three aspects of the evaluation information of mechanics, deformation and heat, so that the evaluation results are more reasonable and complete.
【學(xué)位授予單位】：浙江工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV431

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本文編號：2010826