【作者】 姚爱玲；

【导师】 徐德龙； 张耀君；

【作者基本信息】 西安建筑科技大学 ， 材料学， 2011， 博士

【摘要】 适应高等级公路路面基层与面层结构的新材料始终是该领域的前沿性研究课题之一。添加矿渣微粉尤其是高掺量的使用矿渣粉,不仅能够减少水泥生产中的资源与能源消耗,减少温室气体的排放,而且能够改善各结构层的性能。本文从路面半刚性基层与路面混凝土对水泥性能的要求出发,以尽量多的使用矿渣微粉为基本原则,进行了以矿渣微粉为主要组分的道路上最常用的两种专用水泥胶结材料的研发。综合考虑路面基层材料的技术性能、施工要求和经济性因素,优选了合适的原材料,即矿渣微粉、碱钙硫激发材料(水泥、消石灰、石灰石和石膏)。以凝结时间、抗压强度为主要设计指标,研究矿渣微粉以及激发材料的种类与掺量对胶结材料技术性能的影响。通过凝结时间、抗压与抗折强度、收缩系数试验进行逐级筛选,优选出道路基层专用新型矿渣水泥结合料(New Slag Binder)NSB43A和NSB43B,这两种NSB中矿渣微粉的掺量皆为75wt%,NSB43A中采用的是内掺2wt%石灰石的矿渣微粉,NSB43B中采用了内掺4wt%石灰石的矿渣微粉。这两种矿渣结合料都具有缓凝、抗裂性好、强度高的优点,特别适合路面基层使用。综合考虑路面混凝土的技术性能、施工要求和经济性因素,优选了合适的原材料,即矿渣、碱钙硫激发材料(水泥熟料、石灰石、石膏)、碱性激发剂(Na2SiO3?9H2O和NaOH)、调凝剂。以水泥的凝结时间、抗弯拉强度、抗裂性为主要设计指标,研究矿渣微粉、激发材料以及调凝剂的种类与掺量对水泥胶结材料技术性能的影响,通过凝结时间、抗压与抗折强度、收缩系数试验逐级筛选,考虑尽量覆盖较多的矿渣粉用量范围,优选出了6种配比的性能优良的矿渣道路水泥胶结料(Slag Road Cement)(SRC)。混凝土面层SRC的研究表明:采用熟料、石膏、石灰石以及调凝剂为复合激发材料能够设计出路面混凝土系列水泥。方案中矿渣微粉与熟料用量范围变化比较大,矿渣粉从47~75wt%,熟料从25wt%到50wt%。SRC不仅能够大量使用矿渣粉,抗压强度等级符合道路用水泥技术标准的要求,而且具有抗折强度高、凝结时间合适、经济且环保的优点。在优选出水泥胶结材料最佳配比的基础上,通过室内试验,系统地研究了NSB稳定细粒土、NSB稳定级配碎石、SRC混凝土的路用性能,重点关注NSB稳定土的强度与抗裂性能及施工性能,SRC混凝土的强度与耐久性。采用模糊数学综合评判方法,对比分析了NSB稳定细粒土、稳定级配碎石与P.O32.5 R稳定细粒土、稳定级配碎石,SRC混凝土与P.O42.5R混凝土的综合性能,验证了以矿渣微粉作为主要组分的道路专用水泥的可行性,并分析了专用水泥结合料的适用场合。最后,采用X-射线衍射(XRD)和扫描电镜(SEM)两种方法,对新研制的NSB43A、NSB43B和参照对象P.O32.5R三种结合料及其稳定土进行微观测试,分析了在不同龄期时的水化产物及其形貌。从水泥的粒度分布、孔溶液的pH值、混凝土孔结构、SEM形貌等方面,分析了SRC及其混凝土的水化产物、微观形貌;利用热力学原理,剖析了以矿渣粉为主要组分的水泥孔溶液,在高pH值时引起水化产物C-S-H中低Ca/Si比的原因所在。对NSB、SRC及其稳定土、混凝土的强度形成机理进行了探讨。水化产物的形貌表明以矿渣为主要组分的专用水泥胶结材料的水化产物有较多的钙矾石AFt,而且几乎没有Ca(OH)2的存在,而普通硅酸盐水泥有大量的Ca(OH)2,几乎没有AFt的存在。更多还原

【Abstract】 With the rapid development of road construction, especially the highway construction in China, the researches and application of new materiales for road base courses and pavements have become one of the leading research projects. It has been found that with the addition of ground granulated blast furnace slag (GBFS), especially with large amount of GBFS in addition, the consumption of resources and energy as well as the greenhouse emissions will be reduced, and the faults of the ordinary Portland cement(OPC) will be improved. According to the requirements of road base and concrete surface road on cement features as big as possible , two most commonly used cementitious materials with slag powders as the main component have been developed.The new slag binder NSB43A and NSB43B of road base are chosen after the following three procedures: (A)The selection of the proper raw materials of road base materials such as GBFS and alkali calcium sulfur stimulate materials(cement, slaked lime,limestone, and gypsum), which is based on the consideration of the technical performances, construction requirements and economic factors. (B)The choice of the setting time and compressive strength as the main design index. (C)Relevant choices made in setting time, together with the compressive and flexural strength and contraction coefficient experiment. These two NSB both contain 75wt% GBFS. In NSB43A, 2wt% limestone is contained in its GBFS, whereas in NSB43B, 4wt%. There two slag binder NSB have been proved to be more suitable for road base course with their good performance of slow setting, better anti-crack and higher strength, resulting in economic benefits and environmental protection.Before the systematic research on such factors as GBFS, stimulate materials and the type and dosage of adjustable coagulant on the cementitious material technology performance, construction requirements and economical factors of pavement concrete , the following proper raw materials are chosen: GBFS, alkali calcium sulfur stimulate materials(cement clinker, limestone, gypsum), alkaline stimulate agent(Na2SiO3?9H2O and NaOH),and coagulation agents. Cement setting time, flexural tensile strength, cracking-resistance are taken as the main design index. As a result, six SRC projects have been recommended. The research of the pavement concrete surface of SRC indicates that with the use of adjustable coagulant and composite stimulate materials such as cement clinker, gypsum and limestone, a series of SRC can be designed. In the SRC projects, the amounts of GBFS and clinker dosage vary in comparatively larger ranges, with GBFS powder from 47~75wt% and clinker, 25wt% to 50wt%. These designs have turned out to satisfy cement road technical standard by using large amount of GBFS, producing pavement concrete of greater flexural tensile strength, ideal setting time and the higher compressive strength grade,all of which lead to favorable economic benefits and environmental protection.Based on the above-mentioned optimized compositions and with focus on the strength, anti-cracking performance and construction feature of the NSB stabilized soil,and SRC concrete’s strength and durability, systematic research has been conducted in the indoor experiments on NSB stabilized fine-grained soil, gradation gravel and SRC concrete road performance. Fuzzy comprehensive evaluation method is also used in the experiments in analyzing NSB stabilized fine soil, NSB stabilized gradation gravel and P.O32.5R stabilized soil, SRC concrete and P.O42.5R concrete comprehensive performance in order to testify the feasibility of special road cement with the GBFS powder as the main component and to analyze the applicable occasions of NSB and SRC.Finally, XRD and SEM are employed in the micro-analyses on the newly developed binders and its stabilized soil: NSB43A, NSB43B and their reference material P.O32.5R, and on their hydro-products as well as the photographs of them at different ages. Furthermore, the experiments have also explored into the features of SRC, its hydro-products and corresponding micro-photograph.The study has delved into the reasons of pore bigger solution pH value of newly developed cement and hydration pruductions C - S - H gel lower Ca/Si using thermodynamic principle, in addition to the research of NSB and its stabilized soil, SRC strength mechanism. The photographs of the hydro-products indicate that the biggest differences between special slag cementitious materials and OPC lie in the fact that the former has the comparatively larger amount of AFt and contains little Ca(OH)2, and the latter has larger amount of Ca(OH)2 but little AFt.更多还原