【作者】 徐永红；

【导师】 李凯琦；

【作者基本信息】 河南理工大学 ， 矿产普查与勘探， 2009， 硕士

【摘要】 偏高岭土作为高活性矿物掺合料应用于混凝土中,具有减轻或消除碱骨料反应,提高混凝土的强度和密实性、抗碳化能力和耐酸碱性等优点。针对目前煤矿建设及生产中所用喷射混凝土强度低、脆性大、粘结力不强、回弹率高等问题,依据偏高岭土所具有的特性,用其作为一种矿物外加剂,研制出一种新型高强高性能喷射混凝土,用于煤矿中,可以加强支护体的强度、控制围岩变形、保护支护体不被破坏、减少巷道翻修,并能节约巷道建设和维护成本,保证矿井如期投产和安全生产。重点研究了偏高岭土对喷射混凝土抗压强度的影响:在喷射混凝土中掺入10%的偏高岭土,抗压强度提高40～50%;偏高岭土具有速凝作用,且随着偏高岭土掺量的增加其凝结时间缩短;在掺15%偏高岭土并减少速凝剂用量一半的情况下,喷射混凝土能提高抗压强度40～50%,且初、终凝时间与不减速凝剂用量时相当;环境温度和水温是影响喷射混凝土早期强度的重要因素,温度和水温越高,早期强度越高。通过喷射混凝土水化产物形貌和结构的SEM图像分析,阐明了偏高岭土改善喷射混凝土性能的机理:偏高岭土中的活性组分Al₂O₃和SiO₂能够和水泥水化时产生的Ca（OH）₂反应,且偏高岭土颗粒很细（小于10um）,填充性能良好,所以更好的提高了喷射混凝土的强度。在焦作赵固一矿进行井下现场试验,试验结果表明:喷射回弹率较普通喷射混凝土降低50%;新型喷射混凝土的强度达到了煤矿常用浇注混凝土的强度（C40）;且在原来漏水的地段使用偏高岭土以后,消除了漏水现象。偏高岭土将作为新一代混凝土用高活性矿物外加剂,不仅在煤矿喷射混凝土中得到有效利用,也即将在其它地下工程、薄壁结构工程、维修加固工程、公路和铁路的边坡处理工程、耐火工程和防护工程等土木建筑领域发挥其巨大作用。更多还原

【Abstract】 Mix Metakaolin as a highly active mineral admixture in concrete can reduce or eliminate alkali aggregate reaction, increase strength, density, acid and alkaline resistance, and anti-acid. According to the problems of low strength, brittle, not strong adhesive force, higher rate of rebound in coal mine construction and production。Metakaolin based on the features, as a mineral additive develop a new type of high-strength and high-performance shotcrete. Use it into the building and production in coal mine to enhance strength of support body, can effectively control the surrounding rock deformation, protect the support body and also reduce the renovation of the roadway, thus significantly save the costs of roadway construction and maintenance, and ensure produce on schedule and safely produce.Mainly studied Metakaolin affect the strength of shotcrete, mixed 10% metakaolin in shotcrete, the compressive strength can enhance 40⁵0%; it was found that the metakaolin have rapid setting function, and with the volume of metakaolin to increase its condensation time. The strength of shotcrete could be enhance 40⁵0% ,and the initial and final setting time changeless to the former when mixed 15% metakaolin and reduce by half the amount of quick-setting agent. Ambient temperature and water temperature were the important factors to the early strength of shotcrete, the higher temperature, the higher early strength. Analyzed the SEM images of hydration products appearance and structure in shotcrete, clarified the mechanism of metakaolin improve the performance of shotcrete. The active components Al₂O₃ and SiO₂ in metakaolin can react with the Ca（OH）₂ in cement. And the metakaolin particles are small （less than 10um）, filled with good performance, so it’s better to increase the strength of shotcrete.Did an underground test in Zhaogu No.1 mine of Jiaozuo The test results showed that, the resilience rate of shotcrete was half of the general concrete, eliminated the leak in the original leak place. The strength of new type shotcrete achieved the pouring concrete strength （C40） in coal mine. Metakaolin will use as a new generation highly active mineral admixture in concrete, not only effectively use in shotcrete in the coal mine, but also upcoming use in underground projects, thin-walled structural engineering, maintenance and strengthening works, slope treatment projects of road and rail, fire-resistant engineering and so on. It will play a huge role in civil construction field.更多还原