【摘要】：混凝土作為當(dāng)前應(yīng)用最為廣泛的建筑材料,其開裂后造成的滲漏問題一直困擾著工程界。滲漏問題會影響到混凝土的抗?jié)B性和耐久性,導(dǎo)致混凝土構(gòu)件的承載能力降低。目前,混凝土滲漏的修復(fù)方法有很多,但大都存在著粘結(jié)性及耐久性差、污染環(huán)境等缺點(diǎn)。近年來隨著科技的發(fā)展,微生物誘導(dǎo)碳酸鈣沉積修復(fù)技術(shù)以其修復(fù)效果好、綠色環(huán)保等優(yōu)點(diǎn)逐步成為科研人員的研究重點(diǎn)。該技術(shù)利用微生物新陳代謝活動中產(chǎn)生的尿素酶將尿素分解出碳酸根離子,然后與環(huán)境中的鈣離子結(jié)合生成碳酸鈣晶體沉積于開裂部位,從而實(shí)現(xiàn)對混凝土裂縫的修復(fù)。本試驗(yàn)利用巴氏芽孢桿菌誘導(dǎo)碳酸鈣沉積進(jìn)行混凝土裂縫的封堵,通過設(shè)定不同的影響因素及抗?jié)B試驗(yàn)來檢驗(yàn)其修復(fù)效果。試驗(yàn)的主要內(nèi)容和結(jié)論有：1、研究了菌液中提前加入尿素對碳酸鈣早期產(chǎn)率的影響。結(jié)果表明：在菌液中提前加入尿素可以促使碳酸鈣的生成速率爆發(fā)區(qū)間提前,有效提高碳酸鈣的早期產(chǎn)率。2、試驗(yàn)發(fā)現(xiàn)微生物的活性是影響微生物封堵速度的重要因素。在一定范圍內(nèi),微生物的活性越強(qiáng),誘導(dǎo)產(chǎn)生的碳酸鈣越多,封堵混凝土裂縫的速度越快。3、研究了不同因素(縫寬、縫深、介質(zhì)、鈣源)對微生物灌漿封堵混凝土裂縫的影響。結(jié)果表明：微生物灌漿封堵混凝土裂縫速度的影響因素從大到小依次是縫寬、縫深和介質(zhì)、鈣源；在其它條件不變的情況下,縫寬越小,縫深越大,或在較寬的裂縫中填充介質(zhì)后灌菌等方法可加快裂縫封堵速度。鈣源可以選擇對鋼筋無腐蝕作用的醋酸鈣或硝酸鈣。4、通過沖壓試驗(yàn)研究了微生物封堵完成后混凝土裂縫的抗?jié)B效果。結(jié)果表明：采用微生物修復(fù)技術(shù)封堵的混凝土裂縫具有較好的抗?jié)B性能。裂縫寬度、裂縫深度等都是影響封堵后混凝土裂縫抗?jié)B效果的重要因素。在其它條件不變的情況下,縫寬越小,縫深越大,或在較寬的裂縫中采用先填充介質(zhì)后灌菌等方法,可有效提高封堵后混凝土裂縫的抗?jié)B性能。5、由微生物灌漿封堵混凝土裂縫的機(jī)理可知：裂縫寬度越小越有利于碳酸鈣晶體的捕獲、架橋和沉積。裂縫深度越大,意味著碳酸鈣晶體流經(jīng)裂縫的距離和時間越長,增加了其在混凝土裂縫內(nèi)架橋和沉積的幾率。在寬的裂縫中填充介質(zhì)后,可將裂縫分割為多個小裂縫,同時摩擦力也增加。因此,縫寬越小,縫深越大,或在較寬的裂縫中采用先填充介質(zhì)不僅加快了裂縫封堵速度,而且提高了其抗?jié)B性能。
[Abstract]:Concrete, as the most widely used building material, has been perplexing the engineering field because of the leakage caused by its cracking. Leakage will affect the impermeability and durability of concrete and reduce the bearing capacity of concrete members. At present, there are many repair methods for concrete leakage, but most of them have some disadvantages such as poor adhesion and durability, environmental pollution and so on. In recent years, with the development of science and technology, microbial-induced calcium carbonate deposition remediation technology has gradually become the research focus of researchers because of its advantages such as good remediation effect, green environmental protection and so on. The technology uses urease from microbial metabolism to decompose urea into carbonate ions, and then combine with calcium ions in the environment to form calcium carbonate crystals deposited on the cracking site, so as to repair concrete cracks. In this experiment, calcium carbonate deposition induced by Bacillus pasteurium was used to seal the cracks of concrete, and the repair effect was tested by setting different influencing factors and impermeability test. The main contents and conclusions of the experiment are as follows: 1. The effect of urea on the early yield of calcium carbonate was studied. The results showed that adding urea in the bacterial solution ahead of time could advance the interval of calcium carbonate formation and effectively improve the early yield of calcium carbonate. 2. It was found that the activity of microorganism was an important factor affecting the rate of microbial plugging. Within a certain range, the stronger the activity of microorganisms, the more calcium carbonate induced, and the faster the rate of sealing concrete cracks. 3. Different factors (crack width, seam depth, medium, etc.) Effect of calcium source on microbe grouting to seal concrete cracks. The results show that the influencing factors of microbe grouting sealing concrete crack velocity are crack width, seam depth, medium and calcium source in order from large to small. Under the same other conditions, the smaller the width of the crack, the greater the depth of the seam, or the method of filling the medium with the medium in the wider crack can speed up the sealing speed of the crack. Calcium source can be selected as calcium acetate or calcium nitrate which has no corrosion effect on steel bars. The impermeability of concrete cracks after microbe plugging is studied by stamping test. The results show that the concrete crack sealed by microbial repair technology has better impermeability. Crack width, crack depth and so on are the important factors that affect the anti-seepage effect of concrete cracks after sealing. Under the same other conditions, the smaller the width of the joint, the greater the depth of the joint, or if the medium is filled first and then the bacteria is filled in the wider crack, the impermeability of the concrete crack after sealing can be improved effectively. 5, According to the mechanism of plugging concrete cracks by microbe grouting, the smaller the crack width is, the more favorable it is to capture, bridge and deposit calcium carbonate crystal. The greater the crack depth, the longer the distance and time of calcium carbonate crystal flowing through the crack, which increases the probability of bridging and depositing in the concrete crack. When the medium is filled in a wide crack, the crack can be divided into several small cracks, and the friction force can also be increased. Therefore, the smaller the joint width, the greater the seam depth, or the use of pre-filled medium in the wider cracks not only accelerates the fracture sealing speed, but also improves its impermeability.
【學(xué)位授予單位】：山東建筑大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU528

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