【作者】 赵秀峰；

【导师】 刘开平；

【作者基本信息】 长安大学 ， 材料学， 2008， 硕士

【摘要】 从环境资源学的观点看,煤矸石具有废渣和资源双重属性。煤矸石活化作为辅助性胶凝组分应用到水泥基材料的研究,主要立足于这种工业废渣的“资源化”利用,解决工业生产中的实际问题,达到节约能源、保护环境、变废为宝的目的。本论文通过对煤矸石活性的研究,获得了其最佳活化方式和在普通砂浆中的掺量。同时,干混砂浆具有品质稳定、品种齐全、使用灵活、适应性强等优点,可满足不同工程需要,在我国具有广阔的发展前景。因此,本文在对煤矸石研究的基础上,设计出了掺活化煤矸石、水镁石纤维砌筑干混砂浆的配比。鉴于煤矸石的组成和结构等特性,论文首先采用机械–热复合活化的方法对煤矸石进行活化处理,研究了600～900℃下煤矸石的特性,将活化煤矸石以10%～40%的质量比掺到硅酸盐水泥中,进行水泥砂浆强度试验。并结合X衍射、激光粒度分析、偏光显微等仪器的测试结果对比分析。结果表明,煤矸石进行活化预处理,最佳机械—热复合活化工艺制度为先用球磨机粉磨5小时,加热到700℃后保温7小时,冷却后再粉磨3小时;水泥砂浆强度随活化煤矸石掺量的增加在早期呈下降趋势,但随水化时间的增加,强度有大的提高,甚至超过纯硅酸盐水泥砂浆强度。在活化煤矸石的用量为总灰量的20%的情况下,砂浆28d抗折强度达到最大值,且高出纯水泥砂浆强度2.76%。在30%的掺量下,砂浆28d抗压强度值最大,且高出纯水泥砂浆强度0.33%。分析认为,综合效果以掺量30%为最佳,当掺量超过35%后,强度大幅度下降;煅烧工艺可以提高煤矸石火山灰活性的根本原因是煤矸石中的高岭石矿物在煅烧过程中发生分解,生成了无定形的SiO2和Al2O3。在获得了煤矸石在水泥砂浆中最佳活化方式和最佳掺量后,在原掺煤矸石普通砂浆的基础上掺入水镁石纤维及减水剂进行不同灰矸比和不同灰砂比的水泥砂浆试验,除了抗折抗压强度测试外,还测试了砂浆的粘结强度和稠度。研究表明:在掺加活化煤矸石30%,水镁石纤维3%,萘系减水剂1%的基础上,通过改变灰砂比可配制出不同强度等级的砌筑干混砂浆,且各项指标都符合规范;活化煤矸石具有吸水作用。随着其掺量的增大,水泥砂浆的标准稠度用水量增大,凝结时间相应延长,但对水泥的体积安定性都没有不良影响;复合活化煤矸石可以降低砂浆收缩值,煤矸石具有微集料效应和火山灰效应,可生成致密的水化C-S-H凝胶,填充了孔隙,不仅增加了砂浆的各项强度,同时配合水镁石纤维的骨架支撑作用,使得砂浆干缩率大为减小。通过对掺纤维与不掺纤维砂浆性能的对比分析,发现水镁石纤维与减水剂的加入不仅很好的解决了砂浆的泌水问题,同时改善了砂浆的流动性,提高了砂浆抗压、抗折强度,使得砂浆具有较好的保水、增韧、抗裂性能,再次证明了水镁石纤维在水泥基材料中良好的性能。此外,作者针对实验过程中的优缺点,并结合目前的研究现状提出对掺活化煤矸石干混砂浆研究今后的工作重点和建议。更多还原

【Abstract】 From the view of environmental resources, coal gangue have residue and resources dual attributes. Mainly based on the "resource" utilization of this industrial waste residue, resolving practical problems in the industrial production, purposes of conserving energy protecting the environment and recycling Bao, the activated coal gangue was researched as the complementary cementitious component.In the paper, we received the best activation patterns and the best content of coal gangue in cement mortar by studying the activity of the coal gangue.At the same time, dry-mixed mortar has many advantages such as stable quality, constructing expediently, using byproducts, good to environment, meeting the needs of various projects. It has broad prospects of development. Therefore, in the paper, based on the research of coal gangue, we designed mixture ratio of masonry dry-mixed mortar, which doped activated coal gangue and fibrous brucite.In view of characteristics of composition and structure of coal gangue, the coal gangue was activated by the mean of mechanical–thermal complex activation at first, the characteristic of thermal activated coal gangue at 600～900℃was investigated. The strength of cement mortar was tested after adding the thermal activated coal gangue to Portland cement with a mass fraction of 10%～40%. X-ray diffraction (XRD),differential thermal analysis (DTA),laser-particle size analysis(LPS), polarized optical microscope(PLM) and other modern method of testing were used to analyze the composition and microstructure of the activated coal gangue. The results show that the best mechanical–thermal complex activation is that grinding for the first five hours with ball mill, holding seven hours after heating to 700℃, grinding three hours after natural cooling; The strength of cement mortar descends as content of burned coal gangue increases, but increases with age. The compressive strength at the activated coal gangue content of 30% could reach 61.56MPa,which was 0.33% higher than that of blank specimen. The flexural strength at the activated coal gangue content of 20% could reach 8.56MPa,which was 2.76% higher than that of blank specimen. The best mix quantity is 30%,and the strength descends sharply when the mix quantity more than 35%. active SiO2 and Al2O3 are the main source of coal gangue activity that is created after calcinations of coal gangue analyzed by XRD. After gaining the best activation patterns and the best content of coal gangue in cement mortar,the flexural strength ,compressive strength, bonding strength and consistency of the mortar were tested after adding fibrous brucite and water-reducing agent. The results show that by changing the preparation of gray and sand can be a different intensity levels of dry-mixed masonry mortar at the activated coal gangue content of 30%,the fibrous brucite content of 3%, the Naphthalene superplasticizer content of 1%, and the indicators were in line with norms; Activation gangue with absorbent role. The mortar consumption increased consistency standards, and setting time extended accordingly, but the volume of cement stability were not adversely affected with the increase of Activation gangue content; Complex activation gangue mortar contraction can reduce the shrinkage values of mortar. Because of activated coal gangue have volcanic ash effect and micro-aggregate filling effect,can generate dense hydration C-S-H gel, filling the pores, which not only increased the strength of the mortar, and supported the skeleton supporting role of fibrous brucite, making mortar reduced shrinkage greatly.Through comparative analysis the properties of non-doped fiber and doped fiber mortar found that blending proper quantity of fibrous brucite and water-reducing agent not only resolved the problem of bleeding, but also improved the flowability and strength of cement mortar. The function of water-retaining and anticracking of cement mortar was obvious. It proved that fibrous brucite has a good performance in the cement-based materials once again.In addition, the future work priorities and recommendations were also suggested based on the advantages and disadvantages of the process of experiment and the current status of the activated coal gangue.更多还原