天然水硬性石灰固化机理及其砂浆改性研究

发布时间：2018-11-21 14:41

【摘要】：天然水硬性石灰的使用有悠久的历史,水泥的大量应用使得天然水硬性石灰的应用有所缩减,近年来由于天然水硬性石灰在文物修复领域的优越性其应用有所复苏。关于天然水硬性石灰的研究报道很少。为了弄清天然水硬性石灰的固化机理并对其砂浆进行改性研究,进一步为文物修复提供性能更优的材料,本文从外界环境条件及水灰比对天然水硬性石灰水化与碳酸化过程的影响,及添加硅藻土、碳纤维对天然水硬性石灰砂浆性能的影响两个方面开展研究。结果表明在90天的养护龄期内,水硬性石灰浆液养护过程中与外界的接触状况明显影响其水化与碳酸化进程,接触不充分条件下养护90天时仍存在硅酸二钙与氢氧化钙；接触充分时养护28天内基本完成了水化反应,并且养护14天内氢氧化钙基本完成碳酸化反应。水硬性石灰浆液试样中氢氧化钙的碳酸化速度大于水化硅酸钙的碳酸化速度,水硬性石灰浆液的碳酸化作用促进了其水化反应。水灰比影响水硬性石灰初期水化反应和碳酸化反应。采用硅藻土替代部分水硬性石灰使得砂浆的密度减小,制备砂浆所用原料特别是水硬性石灰的总量减少,硅藻土的加入使得水硬性砂浆试样的强度增加,提高了砂浆的耐酸性、耐冻融性及耐硫酸钠膨胀性能,作用机理为硅藻土与砂浆中氢氧化钙间发生了火山灰反应。添加碳纤维及硅藻土改性碳纤维制备的水硬性石灰砂浆抗折强度有较大幅度提高。硅藻土对碳纤维起到了一定的表面改性作用,它可以与试样中氢氧化钙发生火山灰反应改善碳纤维与砂浆基体之间的界面连接状况而提高试样的强度。添加减水剂大大提高了试样的抗压强度与抗折强度,主要原因为减水剂有利于砂浆基体分散均匀。
[Abstract]:The use of natural hydrated lime has a long history, and the application of natural hydrated lime has been reduced by a large number of cement applications. In recent years, due to the superiority of natural hydrated lime in the field of cultural restoration, its application has recovered. There are few studies on natural hydrated lime. In order to make clear the curing mechanism of natural hydro lime and study the modification of mortar, we can provide better material for restoration of cultural relic. In this paper, the effects of environmental conditions and water-cement ratio on the hydration and carbonation process of natural hydrated lime and the effects of adding diatomite and carbon fiber on the properties of natural hydrated lime mortar were studied. The results show that the contact with the outside world during the curing process of hydrated lime slurry affects the process of hydration and carbonation obviously during the 90 days of curing age, and dicalcium silicate and calcium hydroxide still exist in the condition of insufficient contact. The hydration reaction was basically completed within 28 days and the carbonation reaction of calcium hydroxide was basically completed within 14 days. The carbonation rate of calcium hydroxide in hydrated lime slurry was higher than that of calcium silicate hydrate, and the carbonation of hydrated lime slurry promoted the hydration reaction. The ratio of water to cement affects hydration and carbonation in the initial stage of hydrated lime. Using diatomite to replace part of hydrated lime reduces the density of mortar, reduces the total amount of raw materials, especially hydrated lime, and increases the strength of hydraulic mortar and improves the acid resistance of mortar. The mechanism of freezing and thawing resistance and swelling resistance of sodium sulfate is the reaction of pozzolanic ash between diatomite and calcium hydroxide in mortar. The flexural strength of hydro lime mortar prepared by adding carbon fiber and diatomite modified carbon fiber has been greatly improved. Diatomite has a certain surface modification effect on carbon fiber. It can react with calcium hydroxide in the sample to improve the interfacial connection between carbon fiber and mortar matrix and improve the strength of the sample. The compressive strength and flexural strength of the samples were greatly improved by adding water reducing agent, which was mainly due to the fact that the water reducing agent was favorable to the dispersion of mortar matrix.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ177.61

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