本文選題：鋼纖維混凝土 + 硅灰��； 參考：《重慶交通大學(xué)》2015年碩士論文

【摘要】：鋼纖維混凝土因其優(yōu)良的工作性能而開始在工程中大量應(yīng)用,然而鋼纖維與混凝土基體間薄弱的界面粘結(jié)導(dǎo)致鋼纖維的增強(qiáng)增韌效果難以有效完全發(fā)揮。本論文采用目前常用的添加有機(jī)聚合物和無機(jī)礦物摻和料硅灰來對(duì)混凝土進(jìn)行改性處理,以期提高鋼纖維與混凝土基體間的界面粘結(jié)性能,進(jìn)而增強(qiáng)鋼纖維混凝土的宏觀力學(xué)性能。為此,本論文測(cè)試了不同硅灰和聚合物摻量時(shí)鋼纖維混凝土的抗壓、劈裂抗拉、抗折強(qiáng)度等宏觀力學(xué)指標(biāo);自行設(shè)計(jì)模具及夾具進(jìn)行鋼纖維拉拔試驗(yàn),研究硅灰和聚合物對(duì)鋼纖維—水泥石基體界面粘結(jié)性能的影響;研究了鋼纖維埋置角度、鋼纖維表面形貌以及混凝土基體強(qiáng)度等級(jí)和齡期對(duì)界面粘結(jié)性能的影響;對(duì)界面區(qū)以及水泥石基體進(jìn)行顯微硬度、SEM試驗(yàn)、XRD試驗(yàn)以及低溫氮吸附微觀孔隙測(cè)定等試驗(yàn),從微觀上對(duì)硅灰和聚合物對(duì)鋼纖維與水泥石基體界面粘結(jié)性能的影響和作用機(jī)理進(jìn)行解釋。通過上述這些試驗(yàn)獲得以下結(jié)論:○1硅灰能較好的提高混凝土抗折、抗壓以及劈裂抗拉強(qiáng)度,而聚合物則降低了混凝土的這些力學(xué)性能;單摻鋼纖維時(shí),能一定程度提高混凝土的這些宏觀力學(xué)性能,但存在一個(gè)介于0.6%~0.9%的最優(yōu)摻量;○2硅灰極大地提高了鋼纖維與水泥石基體間的界面粘結(jié)強(qiáng)度,但硅灰摻量超過9%后容易導(dǎo)致鋼纖維被拔斷而瞬間失效,并且硅灰還會(huì)因抑制了鋼纖維自身的彈塑性變形而降低鋼纖維混凝土適應(yīng)變形的能力。而聚合物能提高鋼纖維的極限位移,并能通過對(duì)界面粘結(jié)的弱化而使鋼纖維被拉拔時(shí)不易斷裂而消耗更多的能量,同時(shí)還能提高鋼纖維混凝土適應(yīng)變形的能力;○3在鋼纖維埋置角度為45°時(shí),界面粘結(jié)強(qiáng)度達(dá)到最大,但摻硅灰后傾斜的鋼纖維更容易被拔斷,鋼纖維埋置角度越大該現(xiàn)象越明顯;凸肋形鋼纖維與基體間的界面粘結(jié)強(qiáng)度明顯高于表面光圓的鋼纖維,且界面粘結(jié)強(qiáng)度隨混凝土基體強(qiáng)度的提高而增大,兩者之間存在一定的函數(shù)關(guān)系;○4硅灰能夠增大界面區(qū)顯微硬度值并縮小界面區(qū)與水泥石基體間力學(xué)性能的差距,并有利于水泥的水化反應(yīng),促進(jìn)C-S-H凝膠的生成,抑制Ca(OH)2晶體的產(chǎn)生,降低了界面區(qū)和基體的微觀孔隙體積而改善了界面區(qū)結(jié)構(gòu),有利于提高界面粘結(jié)性能。聚合物雖也能縮小界面區(qū)顯微硬度最小值并一定程度降低了大孔徑的有害孔隙總體積,但其也導(dǎo)致Ca(OH)2晶體含量和尺寸增加,基體顯微硬度的降低,從而界面粘結(jié)性能還是隨聚合物摻量的增加而呈下降趨勢(shì);○5將界面區(qū)的力學(xué)參數(shù)和微觀結(jié)構(gòu)參數(shù)與混凝土結(jié)構(gòu)的宏觀力學(xué)性能聯(lián)系起來,得出界面粘結(jié)強(qiáng)度、鋼纖維拉拔韌度、顯微硬度、比表面積以及微觀總孔體積與混凝土抗壓強(qiáng)度和抗折強(qiáng)度間的函數(shù)關(guān)系式,既揭示了界面區(qū)特征參數(shù)對(duì)混凝土抗壓、抗折強(qiáng)度的影響趨勢(shì),又為預(yù)測(cè)實(shí)際工程中混凝土結(jié)構(gòu)的力學(xué)性能提供了理論基礎(chǔ)。
[Abstract]:Steel fiber reinforced concrete and used widely in engineering because of its excellent performance, however, between the steel fiber and concrete matrix interfacial bonding leads to weak reinforcing and toughening effect of steel fiber is difficult to effectively play completely. This paper uses the present commonly used to add organic polymer and inorganic mineral admixture for modification of silica fume concrete, to improve the interfacial bond strength between the steel fiber and concrete matrix, thus enhancing the macro mechanical properties of steel fiber reinforced concrete. The compressive steel fiber concrete this paper tested different silica fume and polymer dosage, splitting tensile strength, flexural strength and other mechanical parameters; design of tooling and fixture of steel fiber pullout test, effects of silica fume and polymer on the steel fiber cement matrix interfacial bonding properties; steel fiber on buried angle steel fiber surface shape Effect of appearance and the grade of concrete strength and age on interfacial properties; microhardness of interfacial zone, and the cement matrix SEM test, XRD test and low temperature nitrogen adsorption test determination of micro pore, explain and effect of silicon fume and polymer effect on steel fiber and cement matrix bonding mechanism from the microscopic. The following conclusions are obtained through the experiment: 1, silica fume can improve the concrete good bending, compressive and splitting tensile strength, and decreased the mechanical properties of polymer concrete; single doped fiber, can to some extent improve the macro mechanical properties of concrete, but there is an optimal dosage is 0.6%~0.9%; 2, silica fume has greatly improved the interfacial bond strength between steel fiber and cement matrix, but the silica fume quantity more than 9% easily lead to steel fiber were pulled off and Instantaneous failure, and also because of inhibition of steel fiber and silica fume the elastic-plastic deformation of steel fiber reinforced concrete and reduce the ability to adapt to the deformation. And the polymer can improve the ultimate displacement of steel fiber, and by the weakening of the interfacial bond and the steel fiber drawing is not easy to break and consume more energy, but also improve the the deformation capacity of steel fiber reinforced concrete; 3, buried in the steel fiber angle is 45 degrees, the interfacial bond strength reached the maximum, but the steel fiber tilt after silica fume is more likely to be pulled off, steel fiber embedded angle increases, the phenomenon is more obvious; the interfacial bond strength of rib shaped steel fiber and matrix the surface is obviously higher than that of steel fiber light round, and the interfacial bond strength with concrete strength increases, there is a certain relation between them; 4, silica fume can increase the interfacial microhardness value and narrow circle The mechanical properties of the surface area and the gap between the cement matrix, and is conducive to the hydration of cement, promote the formation of C-S-H gel, inhibition of Ca (OH) 2 crystal, reduces the micro pore volume of interfacial zone and matrix and improve the interface structure, can improve the interface bonding performance of polymer is. Can also reduce the interfacial microhardness and the minimum degree reduces the total harmful pore volume of large aperture, but also lead to Ca (OH) 2 crystal content and size increase, decrease the hardness of matrix, thus the bonding performance of the interface or with the polymer dosage increased and decreased 5, the mechanical parameters; the interface and microstructure parameters and macro mechanical properties of concrete structure together, that the interfacial bond strength, steel fiber pull-out toughness, microhardness, surface area and total pore volume of the micro and concrete compressive strength and bending The functional relationship between strength reveals the trend of influence of interface area characteristic parameters on compressive strength and flexural strength of concrete, and provides a theoretical basis for predicting the mechanical properties of concrete structures in actual engineering.

【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU528.572

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