【作者】 张伟；

【导师】 沈燕；

【作者基本信息】 扬州大学 ， 结构工程， 2020， 硕士

【摘要】 传统硅酸盐水泥的生产过程中会消耗大量的能源并且排放出大量CO2,这不利于我国的环境保护和水泥工业的可持续发展,而硫铝酸盐水泥的生产相对硅酸盐水泥具有更低的能耗以及CO2的排放量,同时硫铝酸盐水泥具有良好的早强性、抗冻性、抗渗性、耐腐蚀等特点,但是硫铝酸盐水泥依旧存在—些不足,如凝结时间不易控制、生产成本高昂、后期强度发展缓慢等。为了进一步改善硫铝酸盐水泥的性能,扩大硫铝酸盐水泥的应用,本文研究硼砂和锂盐单掺对硫铝酸盐水泥性能的影响,在此基础上,研究石膏分别对硼砂和锂盐在硫铝酸盐水泥中作用的影响。最后将硼砂和锂盐复合,研究二者复合对硫铝酸盐水泥性能的影响,以期在调控硫铝酸盐水泥的凝结时间的同时不降低硫铝酸盐水泥的力学性能,从而为硫铝酸盐水泥的改性提供参考,也为硫铝酸盐水泥的工程应用提供理论指导和技术支撑。本文研究了硼砂对硫铝酸盐水泥凝结时间、抗压强度、体积稳定性等宏观性能的影响,同时测试了水泥的不同龄期的水化产物。结果表明:在硼砂单掺时,硼砂掺量不足0.1%时,对水泥的缓凝效果并不明显,但是当硼砂掺量达到0.5%时,水泥的凝结时间出现急剧的延长,这说明硼砂掺量的变化对水泥凝结时间的影响并不稳定。适当掺量的硼砂掺入可以有效提高水泥的抗压强度,但是硼砂掺量过多时,水泥的抗压强度则会出现下降。硼砂的掺入可以有效延缓水泥的水化历程。为了进一步研究硼砂对硫铝酸盐水泥的性能影响,本文通过控制水泥中石膏掺量的变化,观察硼砂在不同石膏掺量下对硫铝酸盐水泥性能的影响,结果表明:石膏的掺入可以有效减弱硼砂对水泥的缓凝效果并且减弱硼砂对硫铝酸盐水泥水化产物的影响。其次本文研究了锂盐对硫铝酸盐水泥凝结时间、抗压强度、体积稳定性等宏观性能的影响,同时测试了水泥不同龄期的水化产物。结果表明:单掺锂盐时,0.03%掺量的锂盐掺入可以有效的促进水泥的凝结,但是随着锂盐掺量的增加,水泥的凝结时间趋于稳定,锂盐的掺入可以促进水泥的早期水化历程,但是不利于水泥后期的强度发展。为了进一步研究锂盐对硫铝酸盐水泥的性能影响,本文通过控制水泥中石膏的掺量的变化,观察锂盐在不同石膏掺量下对硫铝酸盐水泥性能的影响,结果表明:石膏的掺入可以有效减弱锂盐对水泥的促凝效果并且减弱锂盐对硫铝酸盐水泥水化产物的影响。最后,本文研究硼砂-锂盐复合对硫铝酸盐水泥的凝结时间、抗压强度、体积稳定性、水化产物等方面的影响,研究结果表明,硼砂掺量较低时,锂盐的掺入可以减弱硼砂对硫铝酸盐水泥的缓凝效果,其中当硼砂掺量为0.5%时,碳酸锂基本不对硫铝酸盐水泥有促凝效果,氢氧化锂对硫铝酸盐水泥有一定的促凝效果但是效果明显减弱;不论是否掺入硼砂,锂盐的掺入会降低硫铝酸盐水泥的后期抗压强度;硼砂-锂盐复合掺入不会改变水泥水化产物的种类,但是,0.1%掺量的硼砂掺入可以有效减弱氢氧化锂对水泥的促凝效果并且提高水泥的抗压强度,同时并不会改变氢氧化锂水泥水化产物种类,但是会减缓氢氧化锂对水泥水化历程的促进效果。更多还原

【Abstract】 The production process of traditional Portland cement consumes a lot of energy and emits a lot of CO2,which is not conducive to China’s environmental protection and the sustainable development of the cement industry.Compared with Portland cement,sulfoaluminate cement consumes less energy which leads to a reduced CO2 emissions,and it shows advantages of early strength,frost resistance,impermeability,corrosion resistance and other excellent characteristics.However,sulfoaluminate cement still has some shortcomings,such as the uncontrollable setting time,the high production cost,and the slowly developed late strength.In order to further improve the performance of sulfoaluminate cement and expand the application of sulfoaluminate cement,this paper focuses on three sections of studies:the effect of single doping borax and lithium salt on the performance of sulfoaluminate cement;the influence of gypsum on borax and lithium salt in the performance of sulfoaluminate cement;the combination effect of borax and lithium on the performance of the sulfoaluminate cement.This paper attempts to find solutions to adjust the setting time of the sulfoaluminate cement without reducing its mechanical properties,and to be kept for reference for the modification of Portland cement,as well as to provide theoretical guidance and technical support for the engineering application of sulfoaluminate cement.This paper also does a further research on the effects of borax on the coagulation time of sulphoaluminate cement,as well as its compressive strength and volume stability.The hydration products of different ages of the cement are tested also.The results show that when the amount of borax is less than 0.1%,the retarding effect on the cement is not obvious,but when the amount of borax is 0.5%,the setting time of the cement is prolonged sharply,which indicates that the effect of varying borax content on the setting time of cement is not stable.Appropriate amount of borax can effectively increase the compressive strength of cement,but when the amount of borax is too much,it will cause the compressive strength of the cement to decrease.The incorporation of borax can effectively delay the hydration process of cement.In order to further study the effect of borax on the performance of sulphoaluminate cement,this paper controls the change of gypsum content in cement to observe the effect of borax on the performance of sulphoaluminate cement under different gypsum content.The results show that:incorporation can effectively reduce the retardation effect of borax on cement and the effect of borax on the hydration products of sulphoaluminate cement.Secondly,the effect of lithium salt on coagulation time,compressive strength,and volume stability of sulphoaluminate cement was studied in this paper,and hydration products of different ages of cement were tested.Here are the results:When the lithium salt is added alone,the addition of 0.03%lithium salt can effectively promote the coagulation of the cement,but with the increase of the lithium salt content,the setting time of the cement basically does not change with the change of the lithium salt content.The incorporation of lithium salt can promote the early hydration process of cement,but is not conducive to the strength development of cement in the later stage.In order to further study the effect of borax on the performance of sulphoaluminate cement,this paper controls the change of the amount of gypsum in cement and observes the effect of lithium salt on the performance of sulphoaluminate cement under different gypsum content.The results show that:Incorporation can effectively reduce the effect of lithium salt on cement setting and the effect of lithium salt on the hydration products of sulphoaluminate cement.Finally,the effects of borax-lithium compound on setting time,compressive strength,volume stability and hydration products of sulfoaluminate cement were studied.The results show that when the borax content is low,the incorporation of lithium can weaken the retarding effect of borax on sulfoaluminate cement.When the borax content is 0.5%,lithium carbonate basically has no coagulative effect on sulfoaluminate cement,while lithium hydroxide has certain coagulative effect on sulfoaluminate cement,but the effect is obviously weakened.The later compressive strength of sulfoaluminate cement was decreased by the addition of lithium with or without borax.Borax-lithium complex does not change the type of cement hydration products,but.The incorporation of 0.1%borax can effectively weaken the coagulative effect of lithium hydroxide on cement and improve the compressive strength of cement,without changing the influence rule of the types of hydration products of lithium hydroxide,but it will slow down the promoting effect of lithium hydroxide on the hydration process of cement.更多还原