【作者】 周吉；

【导师】 水中和；

【作者基本信息】 武汉理工大学 ， 材料学， 2012， 硕士

【摘要】 偏高岭土是一种具有高活性的人工火山灰材料,可以在碱激发的条件下发生火山灰反应,形成水硬性胶凝材料。本文以水玻璃和苛性钠激发偏高岭土,制备偏高岭土基土聚水泥,并重点研究土聚水泥的制备技术及早期强度性能。首先,研究了激发剂中水玻璃模数和碱度对土聚水泥性能的影响；其次,探讨了粉煤灰和矿粉作为外掺剂对土聚水泥性能的影响；再次,研究了养护制度对土聚水泥强度发展的影响规律；最后,探讨了土聚水泥的体积稳定性能。研究结果表明：(1)激发剂是制备土聚水泥的关键因素之一,通过调节激发剂中水玻璃模数和碱度会对土聚水泥流动度和抗压强度产生明显影响,当水玻璃模数为1.4,引入Na2O为偏高岭土质量分数18%时,可以制备出强度较高的土聚水泥,3d强度为38.8MPa,28d强度为46.3MPa。(2)粉煤灰和矿粉作为外掺剂掺入,会对土聚水泥流动度、抗压强度等性能产生明显的影响。其中粉煤灰的“滚珠效应”能有效提高土聚水泥流动性能,在相同水灰比下,掺入15%的粉煤灰能提高浆体21%的流动度；矿粉的高钙含量能提高土聚水泥早期的强度发展,掺入15%的矿粉能使土聚水泥3d抗压强度提高9.3%,28d强度提高7.3%。(3)养护温度是影响偏高岭土基土聚水泥水化的重要影响因素之一,无论早期强度和后期强度都跟养护温度有着密切联系。较高的养护温度能够提升土聚水泥早期的抗压强度,特别是1d强度。在60℃的热养条件下的1d强度比标准养护下强度提高66.7%,但是由于过高的温度和过快的反应速率会使结构形成过快而产生较多裂缝,影响后期强度。(4)与普通混凝土类似,体积收缩是土聚水泥在非载荷情况下开裂的主要原因。由于土聚水泥浆体有着比水泥净浆更高的水灰比,且水化过程中缩聚反应生成水分,所以其后期干缩比水泥净浆大。粉煤灰的掺入能降低土聚水泥的自收缩,当粉煤灰掺入量为胶材15%时,能使土聚水泥的干缩降低38%；而矿粉的掺入则会增加土聚水泥的干缩,当矿粉的掺入为胶材的15%时。,土聚水泥的干缩增加19.9%。更多还原

【Abstract】 Metakaolin is a kind of artificial pozzolanic material with high-activity, which can take pozzolanic reaction in alkaline environment. The paper presents studies on preparation of metakaolin based geopolymer using water glass and sodium hydroxide to, it focus on geopolymer strength development and early strength influence factors. Firstly, to study on water glass modulus and activator alkalinity to geopolymer strength development influence; secondly, to study how fly ash and slag as admixture compound mixture affect on performance of geopolymer; thirdly, study on curing temperature; finally, discusses the drying shrinkage of geopolymer. Research results show that:(1) Change the water glass modulus and alkalinity of activator produced marked effects on the compressive strength of geopolymer. When water glass modulus is1.4and the introduction of Na2O is18%. The highest compressive strength of geopolymer reaches46.3MPa at28day.(2) As mineral admixture, fly ash and slag have a significant effect on fluidity and compressive strength of geopolymer, fly ash can improve the fluidity of geopolymeric cement. Under the same water-cement ratio,15%fly ash can improve21%of the fluidity of paste; Slag can improve the geopolymer early strength development.15%slag can improve9.3%compressive strength of geopolymer at3d.(3)Curing temperature has an essential effect on setting and hardening of metakaolin-based geopolymer. Both early-age and final mechanical properties of geopolymer material are greatly dependent on curing temperature. Higher curing temperatures increase the early-age compressive strengths, which can even reach their target values within1day. Curing temperature at60℃can increase compressive strength66.7%to20℃at Id.But the high temperature and quick formation of the hard structure probably can make cracks. Moreover, the effect of temperature depends on curing time. Curing for just1h at an elevated temperature did not cause remarkable changes in strengths development but longer treatment was responsible for a considerable acceleration of the reaction rate and increase in early-age strengths.(4)As similar as ordinary concrete, drying shrinkage is the main reason for geopolymer to make cracks. As geopolymer paste has a higher water-cement ratio than cement paste and the reaction of water, the dry shrinkage ratio is higher than cement paste. The addition fly ash can reduce the dry shrinkage. When fly ash admixture takes up to15%of cement, the geopolymeric cement shrinkage is decreased38%; the slag admixture can raise geopolymeric cement dry shrinkage. When the slag admixture takes to15%in cement, geopolymer shrinkage is increased19.9%.更多还原