粉煤灰—矿渣复合基矿物聚合物的制备及性能研究

发布时间：2017-12-28 13:41

  本文关键词：粉煤灰—矿渣复合基矿物聚合物的制备及性能研究　出处：《西安建筑科技大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 矿渣 粉煤灰 碱硅酸盐 矿物聚合物 抗压强

【摘要】：近年来,矿物聚合物作为一种新开发的绿色胶凝材料,与硅酸盐水泥相比,矿物聚合物具有生产能耗低、环境友好、强度发展快、耐久性和热稳定好等优势,因此具有广阔的发展前景。本试验以粉煤灰和矿渣组成二元胶凝体系,在碱硅酸盐激发剂作用下,制备得到了粉煤灰-矿渣复合基矿物聚合物材料。以矿物聚合物硬化体的抗压强度作为性能指标,研究了粉煤灰与矿渣的复合比例、碱硅酸盐激发剂的模数与固含量、粉煤灰中CaO的含量、形态以及液胶比等对矿物聚合物性能的影响规律,并结合X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(FT-IR)及核磁共振(NMR)等测试手段,对原材料的微观形貌、化学组成、碱硅酸盐激发剂溶液的结构及矿物聚合物硬化体在固化过程中的反应机理进行分析。同时,对矿物聚合物的耐久性(包括耐高温性能及抗碳化性能)和纤维强化增韧矿物聚合物的性能进行了试验分析。试验结果表明:随着粉煤灰占总胶凝材料比例的增加,硬化体的抗压强度逐渐降低;当碱硅酸盐激发剂固含量为32%时,矿物聚合物的抗压强度随其模数的增大先增大后减小;当激发剂模数为1.2时,其28 d的抗压强度高达102MPa;矿物聚合物的抗压强度随液胶比的增大先增大后减小,当液胶比为0.48时,其抗压强度达到最大;当粉煤灰中CaO为非晶态时,CaO含量越高,矿物聚合物的抗压强度越大;粉煤灰中CaO为晶体状态时,f-CaO在反应过程中形成氢氧化钙导致矿物聚合物后期强度倒缩。抗碳化试验结果表明:碳化早期,矿物聚合物碳化程度大于普通硅酸盐水泥,随着碳化龄期的延长,矿物聚合物GFAN、GFAX与普通硅酸盐水泥的碳化趋势逐渐缓和,与硅酸盐水泥相比,后期矿物聚合物的抗碳化性能较差。耐高温试验结果表明:常温下,矿物聚合物的抗压强度要比普通硅酸盐水泥高,经高温处理后,矿物聚合物的耐高温性能优于普通硅酸水泥。在400℃~1000℃高温煅烧过程中,随煅烧温度的升高,其抗压强度均有所降低,当温度达到1000℃时,矿物聚合物仍留了原始强度的50.1%,并且表面未出现裂纹、疏松等现象。相反,普通硅酸盐水泥的抗压强度几乎丧失,试件严重遭到破坏,表面疏松,裂缝显著变宽。试验进一步探讨了碳纤维与玄武岩纤维对粉煤灰-矿渣复合基矿物聚合物的增韧效果,发现碳纤维与玄武岩纤维均能使粉煤灰-矿渣复合基矿物聚合物力学强度有不同程度的提高,其中抗折强度和抗拉强度增长最为明显,结合试验发现碳纤维增韧效果更佳。当掺入0.5%碳纤维,其7d抗折强度和抗拉强度较不掺纤维分别提高了27.3%和62.1%。
[Abstract]:In recent years, mineral polymer is a newly developed green cementitious material. Compared with Portland cement, mineral polymer has advantages of low energy consumption, environmental friendliness, fast strength development, durability and good thermal stability, so it has broad prospects for development. A two component cementitious system consisting of fly ash and slag was prepared. The fly ash slag composite based mineral polymer material was prepared under the action of alkali silicate activator. The compressive strength of geopolymer hardened as the performance index of fly ash and slag composite ratio, alkali silicate activator modulus and solid content, ash content, morphology and CaO gel ratio on mineral polymer properties, combined with X ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) measurements of microstructure, chemical raw materials, composition, structure and mineral polymer hardened alkali silicate activator solution in the process of curing reaction mechanism analysis. At the same time, the durability of mineral polymers, including high temperature resistance and carbonization resistance, and the properties of reinforced toughened mineral polymers were tested. The test results show that with the increase of fly ash for total cementitious material ratio, compressive strength of hardened body gradually decreased; when the alkali silicate activator when solid content is 32%, the compressive strength increases with the increase of modulus of mineral polymer increased first and then decreased; when the activator modulus is 1.2, the 28 d compressive strength of up to 102MPa the compressive strength of geopolymer; with the increase of liquid binder ratio increases first and then decreases, when water binder ratio is 0.48, the compressive strength reached the maximum; when the fly ash CaO is amorphous, the content of CaO is higher, the greater the compressive strength of geopolymer; fly ash in CaO crystal state, f-CaO the formation of calcium hydroxide resulted in late strength mineral polymer contraction in the reaction process. The test results show that carbonation carbonation early, mineral polymer carbonization degree greater than ordinary portland cement, with the prolonging of carbonation time, carbonization trend of polymer GFAN, GFAX and mineral of Portland cement gradually ease, compared with Portland cement, mineral carbonation resistance of late poly poor complexes. The results of high temperature test indicate that the compressive strength of mineral polymer is higher than that of ordinary portland cement at room temperature. After high temperature treatment, the high temperature resistance of mineral polymer is better than that of ordinary silicate cement. During the calcination at 400 ~1000, the compressive strength decreased with the increase of calcination temperature. When the temperature reached 1000 degrees, the mineral polymer remained at 50.1% of original strength, and there was no crack and porosity on the surface. On the contrary, the compressive strength of the ordinary portland cement is almost lost, the specimen is seriously damaged, the surface is loose, and the crack widens remarkably. Experiment to further explore the toughening effect of carbon fiber and basalt fiber on ash slag based geopolymer composite, carbon fiber and basalt fiber can make the ash slag based geopolymer composite mechanical strength have different degrees of increase, the bending strength and tensile strength increase, combined with the test found that better toughening the effect of carbon fiber. When 0.5% carbon fibers were added, the flexural strength and tensile strength of 7D were increased by 27.3% and 62.1%, respectively, compared with those without fiber.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ177
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本文编号：1346235