秸秆水泥基复合材料性能的研究

发布时间：2018-03-01 00:35

本文关键词： 碱激发碳化秸秆缓凝剂 SEM XRD　出处：《吉林建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：碱激发矿渣-粉煤灰胶凝材料(以下简称碱矿渣粉煤灰水泥)一直是各国学者研究的热点,由于该材料具有优良的力学性能、耐久性以及环保性等而广泛被认可为水泥的替代材料,而秸秆又是我国大量存在的可再生资源,但却因为利用率极低而大部分被燃烧造成了严重的空气污染。因此本文就利用碱矿渣粉煤灰水泥与秸秆的优势性能相结合,相互取长补短,在在获得性能优良制品的同时又为建设资源节约型社会做出了贡献,符合我国可持续发展的战略要求。本文首先对碱矿渣粉煤灰水泥的力学性能进行了研究,又对掺入秸秆后复合材料的环境稳定性、保温性能以及凝结时间进行了探讨,实验结果表明:影响碱矿渣粉煤灰水泥强度各因素的主次顺序是矿渣与粉煤灰的比例〉碱激发剂总量〉水泥熟料〉NaOH与水玻璃比例〉水胶比。并根据正交实验设计确定了最佳配合比,发现矿渣与粉煤灰比例为3:1且碱激发剂总量占15%时强度最好。通过对碱矿渣-粉煤灰水泥强度性能的优化发现,硅灰、硅藻土、水玻璃模数以及粉煤灰和矿渣粉磨时间对胶凝材料强度的提高具有一定的作用。研究发现,当硅灰粉磨时间为10min且掺量在10%时胶凝材料强度最好;硅藻土作为活性掺和料的最佳状态是在600℃条件下煅烧2h,并且用球磨机粉磨5min后以10%的掺入量掺加到胶凝材料中时对强度的提高效果最好;水玻璃模数在1.5-1.9之间时胶凝材料强度逐渐增加,超过2.0时,强度反而出现下降,下降原因与机理值得进一步研究。本文对秸秆碱激发矿渣-粉煤灰水泥的环境稳定性进行了研究,其中秸秆材料又分为了表面碳化秸秆皮和NaOH浸泡秸秆皮、原秸秆皮以及秸秆瓤,发现在抗压强度方面,随着秸秆掺量的增加,胶凝材料的抗压强度都呈现逐渐降低的趋势,但是抗折强度却先有小幅度的增加后又降低,虽然影响趋势相同但是经过表面处理的与未处理的相比,强度下降趋势相对较平缓,并且经过表面碳化的秸秆皮效果最好,对于秸秆瓤来讲,强度下降幅度特别大,当掺量同时为10%时,秸秆瓤是胶凝材料的强度下降到了3.4MPa,而其他秸秆皮依然保持在10 MPa以上,所以秸秆瓤对胶凝材料力学性能影响较大;对于抗冻性,掺入原秸秆皮的胶凝材料能抵抗35次冻融循环,掺入NaOH处理过的秸秆能抵抗45次冻融循环,而掺入表面碳化过的秸秆能抵抗60次冻融循环,充分说明表面碳化对秸秆的处理效果最好。原秸秆皮、表面处理秸秆皮与秸秆瓤对碱矿渣粉煤灰复合材料的保温性能具有较大的提高作用,随着秸秆瓤与秸秆皮掺量的增加,秸秆碱激发矿渣粉煤灰复合材料导热系数呈逐渐降低的作用,当掺量都在10%时,掺加原秸秆皮的胶凝材料的导热系数为0.1145W/m2K,掺入NaOH溶液处理和表面碳化的秸秆皮的导热系数为0.1109 W/m·K和0.1123 W/m·K,而掺加秸秆瓤的复合材料的导热系数为0.1088W/m2K,导热系数有了明显的降低,也说明在保温性能上秸秆瓤好于秸秆皮,但是强度上却差于秸秆皮。秸秆经过粉磨可以作为缓凝剂用来调节碱激发矿渣粉煤灰水泥的凝结时间,与硅灰复合使用时不仅改善了秸秆粉磨时产生的团聚现象,也对碱激发矿渣粉煤灰胶凝材料的凝结时间以及强度产生有利影响,并且研究表明,在合适的掺量条件下,秸秆的缓凝时间可以控制在一定范围内,并且对强度无较大负面影响。
[Abstract]:Alkali activated slag fly ash cementitious materials (hereinafter referred to as the alkali slag and fly ash cement) has been a research hotspot, because the material has excellent mechanical properties, durability and environmental protection etc. and are widely recognized as a substitute material of cement, and the straw is in China there are a lot of renewable resources, but but because the utilization rate is extremely low and most burns caused serious air pollution. So this paper take advantage of properties of alkali slag and fly ash cement and straw combined with each other, to obtain excellent performance products at the same time for the construction of a resource-saving society contribute in, meet the requirements of China's sustainable development strategy this paper first. The mechanical properties of alkali slag and fly ash cement were studied, and the environment on the stability of composite admixture of straw, thermal insulation and setting time are discussed. Please, the experimental results show that the factors influencing order of alkali slag fly ash cement strength is slag and fly ash. The proportion of total alkali activator "cement and water glass." NaOH "ratio of water binder ratio. And the optimum mix ratio according to the orthogonal experimental design, found mine slag and fly ash and the ratio of 3:1 alkali activator that account for 15% of the total strength best. By optimization of alkali slag - fly ash cement strength properties, silica fume, diatomite, improve the modulus of water glass and fly ash and slag grinding time on the strength of cementitious material has certain effect. The study found that when the grinding time is 10min and the strength of silica fume content in 10% when the cementitious material is best; the best condition of diatomite as active admixture is under the condition of 600 DEG C calcined 2h, and 5min after ball mill grinding with 10% admixture added to cementitious materials on the strength of the To improve the effect of the best; the modulus of water glass in 1.5-1.9 between the strength of cementitious materials increased more than 2, the strength decreased, decline reason and mechanism deserves further study. In this paper, straw alkali activated slag fly ash cement stability were studied, including straw material is divided into the surface of the skin and carbonized straw NaOH soak the straw, straw and straw raw flesh, found in the compressive strength, with the increase of straw content, the compressive strength of cementitious materials are decreased, but the flexural strength was first increased slightly and then decreased, while the effect of the same trend but after surface treatment compared with no the strength decreased relatively slowly, and after the surface carbonization of straw straw pulp for the best effect, in terms of strength decreased greatly, at the same time when the content is 10% Straw pulp, is the strength of the cement is down to 3.4MPa, while the other straw remained at more than 10 MPa, so the straw pulp on the mechanical properties of the cementitious materials for greater impact; frost resistance of cementitious materials mixed with raw straw can withstand 35 times of freeze-thaw cycle, the incorporation of NaOH. The straw can withstand 45 times of freeze-thaw cycle, while the incorporation of surface carbonization straw can withstand 60 times of freeze-thaw cycle, fully shows the best treatment effect on the straw surface carbonization. The original straw, straw and straw pulp surface treatment of alkali slag and fly ash composite insulation performance has improved greatly with the increase of straw pulp, straw and straw content, the thermal conductivity of alkali activated slag and fly ash composite was gradually decreased, when the content is 10%, the coefficient of thermal conductivity of cementitious materials mixed with straw raw skin for 0.1145W/m2K, adding NaOH solution Thermal conductivity and surface carbonization of straw was 0.1109 W/m K and 0.1123 W/m K, while adding straw pulp composite material thermal conductivity 0.1088W/m2K, thermal conductivity has been decreased, also shows that in the insulation performance of straw pulp in the straw, but the strength is worse than straw straw. After grinding can be used as retarder to adjust the setting time of alkali activated slag cement and fly ash, silica fume compound use not only improved the agglomeration phenomenon of straw grinding, have favorable effect on the setting time is also activated slag fly ash cementitious material of alkali and strength, and studies show that, in the condition of volume right, slow coagulation time of straw can be controlled in a certain range, and no significant negative effect on the strength.

【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ172.7;TB33

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