地质聚合物材料泛碱的抑制措施研究

发布时间：2018-06-17 16:31

本文选题：泛碱 + 原料组成　；参考：《济南大学》2015年硕士论文

【摘要】：地质聚合物是用含有铝硅酸盐的矿物或工业废渣,在常温条件下,通过碱激发剂制备的一种新型的硅铝质的无机高分子材料。具有快硬早强,耐高温,耐腐蚀,抗渗性好的优点。同时,地质聚合物材料也存在限制其实际推广应用的缺陷:脆性大,收缩率高,成本高,另外,由碱激发得到的地质聚合物中含有大量的可溶性碱,会随着水分的挥发而浸出,容易引起碱-集料反应,使得材料膨胀变形,并且会腐蚀混凝土中金属骨架,对材料的安定性造成不良影响。因此,地质聚合物的改性研究也成为现阶段地质聚合物研究的重要组成部分,同时对地质聚合物实现实际应用具有重要意义。本文以钢渣、矿渣、砂子为原料,以NaOH作为激发剂,在20MPa的压力下,采用模压成型制备了废弃物基地质聚合物。针对地质聚合物可溶性碱溶出(泛碱)问题,依据泛碱的形成机理,制定研究方案;通过对其泛碱程度、力学性能、孔结构、微观形貌以及水化矿物组成等进行分析,得到主要研究结果及结论如下:1.掺加掺合料分别为粉煤灰、硅灰、5A沸石、钙基膨润土对地质聚合物材料进行改性。结果表明:(1)用粉煤灰部分替代原料钢渣及矿渣,由于粉煤灰的微集料作用和火山灰作用,对地质聚合物材料的泛碱具有一定的抑制作用。其中粉煤灰掺量为15wt%时,地聚物材料浸出液的CO32-相比未掺加粉煤灰的试样下降51%,抑制效果最明显。(2)硅灰能够提高地质聚合物中的Si/Al比,有利于地质聚合反应,提高材料致密度及力学性能,对泛碱具有抑制作用,掺量为10wt%时,性能最优,养护60d抗压强度可达102.5MPa。(3)5A沸石中的Ca2+与地质聚合物中的Na+离子进行离子交换反应能固定Na+并有效抑制泛碱现象。同时,由于被置换出的Ca2+溶解度较低,在结构内部形成沉淀,它的出现能为地质聚合物的形成提供更多的形核位置,从而有利于加速地质聚合物反应,提高抗压强度。(4)用10wt%钙基膨润土代替一定比例的钢渣和矿渣制备地质聚合物,可提高样品抗压强度,样品60d抗压强度达74.5MPa,钙基膨润土对Na+的吸附作用使得它的添加还有利于减小样品的泛碱程度。通过研究发现,粉煤灰、硅灰及5A沸石对废弃物基地质聚合物的泛碱具有很好的抑制作用,最佳掺量分别为15wt%、10wt%、15wt%。2.改变碱激发剂的种类和掺量,对地质聚合物泛碱也会具有很明显的影响作用。用KOH等量替代NaOH作为激发剂制备的地质聚合物材料的浸出液的CO32-浓度1600.3mg/L相较于以NaOH作为激发剂制备的材料的NaOH作为激发剂离子浓度2500.3mg/L下降了35%;以Na2SiO3作为激发剂时,在掺量相同的情况下所制备的材料相较于以以NaOH作为激发剂的材料的浸出液的离子浓度降低71%。但是用Na2SiO3作为激发剂时60d抗压强度51.2MPa低于用NaOH作为激发剂的材料的强度。最优的激发剂为KOH,掺量为3wt%。3.养护的温度和湿度对地质聚合物的泛碱程度有很大的影响。养护条件为40℃/90%时,样品浸出液的CO32-离子浓度最低,为1375.0mg/L,即在此条件下地质聚合物材料的泛碱程度最低。同时,其养护28天抗压强度最大,可达99.7MPa。4.加入减水剂后,可以减少用水量,使得水化后的地质聚合物的内部孔径减小,改善孔结构,使结构变得更加致密。其中减水剂掺量为0.6wt%时,试样浸出液的离子浓度为1845.3mg/L,相比于未掺加减水剂的空白组离子浓度2520.4mg/L降低了28%。掺加硅烷防水剂后,防水剂会与结构材料发生化学反应,在材料试样表面上生成一层几个分子厚的不溶性防水树脂薄膜。当在掺量为0.4%时浸出液的离子浓度最小,为1753.9mg/L,相较于对照组浸出液离子浓度2520.4mg/L(未掺加外加剂)有明显的降低。掺加减水剂和防水剂对地质聚合物泛碱有抑制作用,最佳掺量分别为0.6wt%和0.4wt%。
[Abstract]:Geopolymer is a new type of silicalic inorganic polymer prepared by alkali activator with aluminosilicate containing mineral or industrial waste. It has advantages of fast hardening, high temperature resistance, high temperature resistance, corrosion resistance and impermeability. It has large sex, high shrinkage and high cost. In addition, a large amount of soluble alkali is contained in geopolymer excited by alkali, which will leach with the volatilization of water, easily cause the alkali aggregate reaction, cause the material to expand and deform, and will corrode the metal skeleton in the concrete, and have a bad effect on the stability of the material. Therefore, geological polymer The modified research has also become an important part of the study of geological polymers at the present stage. At the same time, it is of great significance for the practical application of geopolymers. In this paper, steel slag, slag and sand are used as raw materials and NaOH as a activator. Under the pressure of 20MPa, the waste based geopolymer is prepared by molding. The main research results and conclusions are obtained by analyzing the degree of alkalinity, mechanical properties, pore structure, micromorphology and hydrated mineral composition and so on. The main results and conclusions are as follows: 1. admixtures are divided into fly ash, silica fume, 5A zeolite and calcium bentonite on geological polymers. The material is modified. The results show that: (1) the use of fly ash partly replace the slag and slag of raw material. Due to the micro aggregate action of the fly ash and the effect of volcanic ash, it has a certain inhibitory effect on the general alkali of the geopolymer material. When the fly ash content is 15wt%, the CO32- of the leaching solution of the geopolymer material is reduced by 5 compared with the sample without the fly ash. 1%, the inhibition effect is the most obvious. (2) silica fume can improve the Si/Al ratio in geopolymer, be beneficial to the geological polymerization, improve the density and mechanical properties of the material, and have the inhibition effect on the alkali. When the dosage is 10wt%, the performance is optimal, and the compressive strength of 60d can reach 102.5MPa. (3) 5A zeolite and the Na+ ion in the geological polymer. The subexchange reaction can immobilization of Na+ and effectively inhibit the phenomenon of Pan alkali. At the same time, due to the low solubility of the replaced Ca2+, the precipitation can be formed inside the structure, and its appearance can provide more nucleation position for the formation of geological polymers, which is beneficial to accelerating the reaction of Geopolymer and improving the compressive strength. (4) replacing one with 10wt% calcium bentonite. The preparation of geopolymer with proportional steel slag and slag can improve the compressive strength of the sample, and the compressive strength of the sample 60d is up to 74.5MPa. The adsorption of Na+ on the calcium bentonite is beneficial to the reduction of the degree of alkali in the sample. The best doping amount is 15wt%, 10wt% and 15wt%.2., which changes the type and content of alkali activator, and it also has a significant effect on the geological polymer alkaloids. The CO32- concentration 1600.3mg/L in the leaching solution of the geopolymer prepared by NaOH as a activator and 1600.3mg/L phase is compared with NaOH as a activator. The NaOH of the material decreased by 35% as the ionic concentration of activator 2500.3mg/L; when Na2SiO3 was used as a activator, the material prepared in the same dosage was lower than the ionic concentration of the leaching solution of the material with NaOH as a activator, but the 60d compression strength 51.2MPa was lower than NaOH when Na2SiO3 was used as a activator. The strength of the material of the hair agent. The optimum activator is KOH and the temperature and humidity of the 3wt%.3. curing has a great influence on the degree of alkali pan in the geological polymer. When the curing condition is 40 C, the concentration of CO32- ion in the sample leaching solution is the lowest, which is 1375.0mg/L, which is the lowest degree of alkali in the geopolymer under this condition. At the same time, it is the lowest. After curing for 28 days, the compressive strength is maximum, and the water consumption can be reduced after adding 99.7MPa.4. to the water reducing agent. The inner pore size of the geopolymer after hydration is reduced, the structure of the hole is improved and the structure becomes more compact. When the amount of water reducing agent is 0.6wt%, the concentration of the extract of the sample is 1845.3mg/L, compared with the air without adding water reducing agent. After the white group ion concentration 2520.4mg/L reduces the 28%. addition of silane waterproofing agent, the waterproof agent will react with the structural material to produce a layer of insoluble waterproof resin film on the surface of the material. When the content is 0.4%, the ion concentration of the leaching solution is the smallest, which is 1753.9mg/L, compared to the concentration of the ion concentration in the control group. The degree of 2520.4mg/L (without admixture) is obviously reduced. The addition of water reducing agent and waterproofing agent have the inhibition effect on the geopolymer, the best dosage is 0.6wt% and 0.4wt%., respectively.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU52

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