發(fā)布時(shí)間：2018-03-25 07:54

  本文選題：自密實(shí)混凝土　切入點(diǎn)：橋梁　出處：《燕山大學(xué)》2014年碩士論文

【摘要】：隨著國民經(jīng)濟(jì)的飛速發(fā)展，作為樞紐工程，橋梁建設(shè)也因此迎來了一個(gè)高峰期�；炷潦菢蛄航ㄔO(shè)中最主要的材料，如何保證橋梁混凝土質(zhì)量成為人們關(guān)注的焦點(diǎn)。 本文根據(jù)秦皇島地區(qū)混凝土橋梁質(zhì)量的調(diào)查分析，提出采用自密實(shí)混凝土方法來解決橋梁混凝土出現(xiàn)的表觀質(zhì)量問題。自密實(shí)混凝土由于漿集比大，，膠凝材料用量多，彈性模量相對較低，成為應(yīng)用于橋梁的劣勢。針對橋梁混凝土對早期強(qiáng)度和彈性模量的特殊要求，以及秦皇島地區(qū)缺乏優(yōu)質(zhì)礦物摻合料的現(xiàn)狀，采用理論分析和實(shí)驗(yàn)研究相結(jié)合的方式，通過降低水膠比、優(yōu)化粉煤灰摻量和砂率等主要參數(shù)，制備出了7d抗壓強(qiáng)度為46.1MPa、28d抗壓強(qiáng)度為61.4MPa和彈性模量為36.6GPa的橋用自密實(shí)混凝土。 研究結(jié)果表明：現(xiàn)有自密實(shí)混凝土配合比計(jì)算方法均沒有考慮橋用混凝土對早期強(qiáng)度和彈性模量的特殊要求，以及缺乏優(yōu)質(zhì)礦物摻合料的現(xiàn)狀，因此需要對計(jì)算出的自密實(shí)混凝土配合比參數(shù)進(jìn)行調(diào)整；二級粉煤灰的細(xì)度不夠，其對膠凝材料凈漿流動度改善作用不明顯，起不到微集料填充作用，不能通過置換出漿體中的填充水來提高流動性；采用本文選用的材料，在膠凝材料總量為530kg/m3時(shí)，自密實(shí)混凝土的強(qiáng)度值最高，當(dāng)膠凝材料總量增大到570kg/m3時(shí)強(qiáng)度反而降低；砂率對自密實(shí)混凝土工作性能有很大影響，隨著砂率的增大，自密實(shí)混凝土的流動性先增大再減小，最佳砂率為45%；制備出的自密實(shí)混凝土比秦皇島地區(qū)使用的同強(qiáng)度等級的混凝土每立方米節(jié)省成本16.78元，技術(shù)經(jīng)濟(jì)效果明顯，具有廣闊的推廣前景。
[Abstract]:With the rapid development of the national economy, as a hub project, bridge construction also ushered in a peak period. Concrete is the most important material in bridge construction, how to ensure the quality of bridge concrete has become the focus of attention. Based on the investigation and analysis of the quality of concrete bridges in Qinhuangdao area, a self-compacting concrete method is proposed to solve the apparent quality problems of bridge concrete. The elastic modulus is relatively low, which becomes the disadvantage of bridge application. In view of the special requirement of early strength and elastic modulus of bridge concrete, and the lack of high quality mineral admixture in Qinhuangdao area, By means of theoretical analysis and experimental study, by reducing the ratio of water to binder and optimizing the content of fly ash and sand ratio, the self-compacting concrete for bridges with 7d compressive strength of 46.1 MPA / 28d and elastic modulus of 36.6GPa was prepared. The results show that the present calculation methods of self-compacting concrete mixture ratio do not take into account the special requirements of bridge concrete for early strength and elastic modulus, as well as the present situation of lack of high quality mineral admixture. Therefore, it is necessary to adjust the parameters of the calculated self-compacting concrete mixture ratio. The fineness of the secondary fly ash is not enough, and the effect of the secondary fly ash on the flow of cement paste is not obvious, which can not play the role of micro-aggregate filling. The strength of self-compacting concrete is the highest when the total amount of cementing material is 530kg/m3, but the strength of self-compacting concrete decreases when the total amount of cementing material increases to 570kg/m3. Sand ratio has a great influence on the working performance of self-compacting concrete. With the increase of sand ratio, the fluidity of self-compacting concrete increases first and then decreases. The best sand rate is 450.The prepared self-compacting concrete saves 16.78 yuan per cubic meter compared with the same strength concrete used in Qinhuangdao area.
【學(xué)位授予單位】：燕山大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U444

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