【作者】 李贵强；

【导师】 芦令超；

【作者基本信息】 济南大学 ， 材料学， 2011， 硕士

【摘要】 2010年我国水泥产量达18.7亿吨,导致能源和资源消耗巨大,环境污染日益严重。因此,如何实现水泥工业的可持续发展是当前面临的主要任务。高质量建设工程要求水泥与混凝土施工性更好、强度更高及具有良好的耐久性,并要求水泥生产和使用过程中能够利用更多的工业废弃物。生产高性能水泥的关键是制备高胶凝性水泥熟料,而提高水泥熟料中阿利特含量是制备高胶凝性水泥熟料的有效途径之一;另外,在水泥熟料中引入非硅酸盐类高胶凝性矿物形成新的高胶凝性熟料矿相体系也是制备高胶凝性水泥熟料的重要方法。本文通过在高阿利特水泥熟料中分别掺杂SrO和SrSO₄,研究了其对高阿利特水泥熟料制备、结构和性能的影响。在高阿利特水泥熟料中掺杂SrO与SrSO₄以形成少量具有快硬早强性能的硫铝酸锶钙矿物,制备了硫铝酸锶钙改性高阿利特水泥熟料。采用正交实验方法确定了该熟料适宜的煅烧制度和组成。通过研究掺杂SrO和SrSO₄的C₃S晶体结构的变化及性能,获得了提高C₃S水化活性的有效方法。采用XRD、SEM-EDS、IR、水化热和岩相分析等测试手段对熟料和矿物的组成、结构和性能进行了分析,初步阐明了掺杂SrO和SrSO₄条件下提高该水泥性能的机理。主要结论如下:在1450℃煅烧条件下,在本实验组成范围内,高阿利特水泥熟料的适宜率值为:KH=0.92、SM=2.5、IM=1.5,C₃S的计算含量达65.1%;在该条件下制备的高阿利特水泥1d、3d和28d抗压强度分别达到了23.4MPa、53.7MPa和129.1MPa,展现了良好的力学性能。KH值过高时,阿利特含量没有明显增加,反而易造成水泥熟料的煅烧困难。掺杂SrO和SrSO₄可以降低熟料中游离氧化钙的含量,促进阿利特矿物的形成,有利于水泥强度的提高。掺杂SrO的高阿利特水泥熟料的最佳制备条件为:煅烧温度为1450℃、保温时间为60min、SrO的适宜掺量为1.5%（质量分数,下同）,水泥早期力学性能明显提高,3d强度可提高15.5%。掺杂SrSO₄的高阿利特水泥熟料的最佳制备条件为:煅烧温度为1450℃、保温时间为60 min、SrSO₄的适宜掺量为0.5%,水泥后期力学性能明显提高,28 d强度可提高9.9%。引入硫铝酸锶钙矿物可以降低高阿利特水泥熟料体系烧成温度约100℃,并使熟料中游离氧化钙含量降低,促进阿利特矿物形成。在本实验条件下,硫铝酸锶钙改性高阿利特水泥熟料的最佳制备条件为:煅烧温度为1350℃、保温时间为60 min、硫铝酸锶钙的引入量为2%。所制备的水泥1d、3d和28d抗压强度分别达到了28.5MPa、66.7MPa和128.6MPa,力学性能良好。熟料中阿利特和硫铝酸锶钙矿物的发育程度均不够完整,矿物尺寸较小;硫铝酸锶钙矿物尺寸约为0.1μm,存在于硅酸盐矿物边界和空隙。同时,研究了掺杂SrO和SrSO₄对C₃S晶体结构和性能的影响。结果表明:试样中游离氧化钙含量随SrO掺量的增加而逐渐增多,但当SrO掺量小于0.075mol时,其游离氧化钙含量较低且低于纯C₃S。当SrO掺量小于0.025mol时,硅酸三钙固溶体衍射峰发生变化但均为三斜晶系;当SrO掺量大于0.025mol时,硅酸三钙固溶体为单斜晶系。随着SrO掺量的增加,硅酸三钙固溶体在815cm-1吸收谱带由尖锐逐渐消失,取代程度增加,其对称性提高。掺杂SrO硅酸三钙的加速期提前,水化速率增大,使硅酸三钙固溶体有更大的水化活性。当SrSO₄掺量较少时,可降低试样中游离氧化钙含量,促进C₃S的形成;但当SrSO₄掺量逐渐增大时,试样中的游离氧化钙含量逐渐升高。掺杂1.5% SrSO₄的硅酸三钙晶型为R型。掺杂SrSO₄以后C₃S在815cm-1吸收谱带也由尖锐逐渐消失。更多还原

【Abstract】 In 2010, the cement output reached 1.87 billion tons in China, which leads to enormous consumption of energy and natural resources as well as severe environmental pollution. Therefore, the main task is how to achieve the sustainable development of cement industry. The key to producing high-performance cement is the preparation of cement clinker with high cementitious. The effects of doping SrO and SrSO₄ on the preparation, structure and properties of the alite-rich cement clinker are studied. Alite-rich cement clinker modified by calcium strontium suphoaluminate is prepared by introducing calcium strontium suphoaluminate mineral with rapid hardening and early strength performances into alite-rich cement clinker. The optimum composition and sintering condition of the clinkers are determined by the orthogonal experimental method. The crystal structures and properties of C₃S doped SrO and SrSO₄ are also researched. The test methods, such as XRD, SEM-EDS, IR, heat of hydration and lithofacies analysis, are used to analyze the composition, structure and performance of clinker and mineral. The main conclusions are as follows:Calcined at 1450℃, the appropriate modulus value of alite-rich cement clinker is as follows: KH=0.92, SM=2.5, IM=1.5, and the calculation content of mineral composition C₃S is up to 65.1%; Under this conditions, the 1d, 3d and 28d compressive strength of alite-rich cement are 23.4MPa, 53.7MPa and 129.1MPa respectively, showing excellent mechanical properties. Overvalue KH of cement clinker doesn’t contribute to obvious increase of alite; instead, it results in the difficulties for the sintering of clinker.Cement clinker doped SrO and SrSO₄ can reduce the contents of free calcium oxide, promote the formation of alite minerals, and be benefit to the improvement of cement strength. The optimum conditions for alite-rich clinker doped SrO are as follows: sintering temperature is 1450℃, sintering time is 60 min, and the appropriate content of SrO is 1.5% （by the mass, the same as following）. The early strength of cement increases significantly, and the 3d strength can be improved by 15.5%. The optimum conditions for alite-rich clinker doped SrSO₄ are as follows: sintering temperature is 1450℃, sintering time is 60 min, and the appropriate content of SrSO₄ is 0.5%. The later strength of cement increases significantly, and the 28d strength can be improved by 9.9%.The introduction of calcium strontium suphoaluminate mineral can not only reduce the sintering temperature of alite-rich cement clinker to about 100℃, but also decrease the contents of free calcium oxide and promote the formation of alite minerals in clinker, which can play important role in the energy saving of cement industry. Under the experimental conditions, the optimum conditions of alite-rich cement clinker modified by calcium strontium suphoaluminate are as follows: sintering temperature is 1350℃, sintering time is 60 min, and the content of calcium strontium suphoaluminate is 2%. Under the optimum preparation conditions, the 1d, 3d and 28d compressive strength of cement are 28.5MPa, 66.7MPa and 128.6MPa respectively and excellent mechanical properties. The development degree of alite and calcium strontium suphoaluminate minerals in the clinker is incomplete, and the size of mineral particles is small. The size of calcium strontium suphoaluminate minerals is about 0.1μm, existing in the gaps and borders of silicate minerals.The effect of SrO and SrSO₄ on the crystal structure and properties of C₃S is also researched. The content of free calcium oxide increases with the increase of SrO, when the content of SrO is less than 0.075mol, the content of free calcium oxide is lower than that of the pure C₃S. When the SrO content is less than 0.025 mol, the diffraction peaks of tricalcium silicate solution show slight change but its crystal type is still triclinic; when the doping content of SrO is more than 0.025 mol, the tricalcium silicate solution is the monoclinic. As the increase of replacement level, the sharp extent of its absorption band decreases. After the doping of SrO, the absorption band of C₃S at 815cm-1 become to gradual disappearance from the very sharp spectrum, resulting in greater hydrate tendency of tricalcium silicate solutions. When the doping content of SrSO₄ is small, the content of free calcium oxide can be reduced in sample and consequently the formation of C₃S can be promoted. However, with the increase of the SrSO₄ content, the content of free calcium oxide in samples increases gradually. The characteristic of the R-C₃S solution sample mixed with 1.5% SrSO₄ is that the absorption band of C₃S at 815cm-1 gradually disappears from the very sharp spectrum.更多还原