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类型 基础研究 预答辩日期 2017-11-28
开始(开题)日期 2015-12-09 论文结束日期 2017-09-28
地点 高性能土木工程材料国家重点实验室5300会议室 论文选题来源 973、863项目     论文字数 8.3 (万字)
题目 核壳纳米SiO2 改性水泥基材料性能研究
主题词 水泥,纳米二氧化硅,核壳结构,水化加速,表面涂覆
摘要 水泥基材料,是人类使用最大宗的建筑材料。水泥制造的碳排放量,约占全球碳排放总量的百分之八,低碳问题是水泥基材料发展面临的重大挑战。技术层面上,合理利用辅助胶凝材料和提升耐久性,是缓解低碳问题的两个重要途径。 纳米技术冲击了科学研究的每个角落,水泥混凝土领域也不例外,各种纳米粒子,已经用于改性水泥基材料,例如,纳米二氧化硅、纳米氧化铝、氧化石墨烯等。传统与现代的碰撞,赋予了水泥基材料新的活力。纳米材料虽然性能卓越,但与水泥相比,高昂的价格限制了其在本行业的发展与应用。因此,研究价值和应用价值的交叉区域更具现实意义。纳米二氧化硅(NS),作为本行业经济成本最低和应用最广泛的纳米材料之一,结合低碳问题背景,目前它的价值交叉区域主要集中在两个方向:其一内掺NS,利用其早期加速效应补偿辅助胶凝材料的延缓作用。其二表面涂覆NS,密实化水泥基材料表面,提高基体耐久性。NS的作用效果强烈依赖其在基质中的分散性能,实现NS的有效分散仍然是一项重要挑战。 基于上述背景,为了提升NS的分散性,并将其合理地应用于改性水泥基材料,本文主要在四个方面展开了研究:其一,针对分散性提升,研究了核壳NS的合成;其二针对早期加速效应提升,研究了一系列核壳NS分子结构和水化加速效应的关系,探明最佳的结构和适宜的掺量;其三,针对表面涂覆应用,以毛细吸水性能为切入点,探究不同结构核壳NS改性效果,研究核壳NS密实化基体表面机理 。其四,为了丰富核壳NS降低基体吸水性能机理,从界面能的角度,研究不同C-S-H表面和水分子的相互作用。 本文所取得的主要创新研究成果如下: (1)提出了通过核壳结构提高NS分散性的构想,采用“grafting to”法,合成了一系列纳米二氧化硅-聚羧酸共聚物核壳纳米粒子(NS@PCE),验证了“核壳结构建立→纳米分散性能提升→水化加速效应增强”路径的可行性。 (2)研究了NS@PCE内掺对早期水化性能影响,采用等温水化量热法等实验手段,建立了NS@PCE核壳结构和早期水化加速效应之间的构效关系。 (3)探索了NS@PCE作为表面涂覆材料密实化水泥基表面的应用,采用吸水性能评价了表面处理后水泥基材料的毛细渗透性能,结合纳米粒子的分散性能和火山灰效应,提出了一个假说,揭示了核壳纳米粒子表面处理的机理。 (4)研究了C-S-H表面变化后与水分子之间的相互作用,采用分子动力学方法,从纳观尺度,探寻了不同钙硅比C-S-H表面和PCE锚固C-S-H表面后与水分子相互作用机理,从界面能角度,揭示了亲水疏水与界面的关系,丰富了核壳NS改性水泥基表面机理。 本文的研究对纳米改性水泥基研究方向,有如下启示意义:其一,纳米粒子的分散性提升可以通过构造核壳结构来解决,PCE是最具潜力的壳构造聚合物;其二,纳米材料的表面性质对其性能发挥有举足轻重的作用,杜绝简单拿来主义,构造适宜水泥基材料体系的纳米材料表面,是放大纳米材料价值的重要途径;其三,表面涂覆应用方兴未艾,能够极大降低纳米粒子应用成本,是纳米粒子在本领域的重点发展方向。
英文题目 MODIFYING CEMENTITIOUS MATERIALS WITH CORE-SHELL NANO-SiO2
英文主题词 cement, nano-silica, core-shell structure, nano modified, acceleration effect, surface-treatment
英文摘要 Cement-based materials, is still the most consumed building materials in the world. Cement production is currently responsible for about 8% of the global CO2 emission. Low carbon is a major challenge for cementitious materials. From the perspective of technology, the rational utilization of supplementary cementitious materials and the improvement of durability, is two key methodologies to alleviate the low carbon problem which cementitious materials confront in the process of development. Nanotechnology has shocked every corner of scientific research, of course, cement and concrete research area is no exception. Many kinds of nanoparticles have been used to modify cementitious, such as nano-silica, nano-alumia, graphene oxide, and so on. The collision between tradition and modernity motivate the new vitality of cement-based materials. For nanomaterials, they have superior performances, however, compared with cement, high price limits their extensive application in the industry. Therefore, the cross region between research value and application value seem more closed to reality. Nano-silica (NS), as one of most widely used nanomaterials as well as the lowest price, in cement and concrete area, combined the low-carbon problem background, its cross region focuses in two main directions: the first one is to utilize the early acceleration effect of NS to compensate the retardation effect of supplementary cementitious materials as kind of additive. The second one is to utilize NS as kind of surface-coated agents, to densify the surface areas of harden cementitious matrix resulting in the improvement of durability. The effect of NS is strongly dependent on its dispersion in the cementitious matrix, however, the effective dispersion of NS remains a big challenge. Based on the background discussed above, to promote the dispersibility of NS and apply NS in a reasonable way, this paper carry out a series of studies from four main aspects: Firstly, to address the issue of the dispersion of NS, we synthesize a series of NS@PCE core-shell nano-particles, secondly, for enhancing the early acceleration effect, the relationship between the molecular structures of a series of NS@PCE and acceleration effect was studied. thirdly, for the surface-treatment application of NS, we studied the effects and mechanism of surface-treatment of cementitious with NS@PCE, which, fourthly, to enrich the mechanism of reducing water absorption performance, we adopted the molecular dynamics simulation, to study the interaction between water and C-S-H or C-S-H-PCE from the view of interface energy. The main innovations of this paper are as follows: (1) A conception, improving the dispersion of NS by core-shell structure, is first proposed in this area. A series of nano-silica-polycarboxylate acid copolymer core-shell nanoparticles have been synthesized by“grafting to”method. The feasibility that the formation of core-shell structure→dispersion enhanced→acceleration effect promoted, is verified. (2) The influence of NS@PCE on the early hydration performance is studied. The relationship between the molecular structures of a series of NS@PCE and acceleration effect is elucidated by series of experimental methods, especially isothermal calorimetry. (3) The application of NS@PCE as a kind of surface-treatment agent is explored. Combined the dispersion properties and pozzolanic reactivity of NS@PCE, a hypothesis is proposed to reveal the mechanism of surface-treatment process of nanoparticles. (4) The interaction between water and C-S-H is studied by the molecular dynamics simulation method. In nanoscale, we uncover interaction mechanism between C-S-H with different calcium-silicon ratio or PCE modified C-S-H and water. From the perspective of interface, we revel the hydrophilic or hydrophobic of different interfaces, which enrich the surface-treatment mechanism of nanoparticles. The research of this paper has the following enlightenment meaning for nano-modifying cement based materials research: firstly, the dispersion of nanoparticles can be improved by constructing the core-shell structure not limited to nano-silica, and PCE is the most potential polymer for shell structure. Secondly, the surface property of the nanomaterials plays a decisive role in their performance. we should put an end to “simple take” when nanoparticles used in this area, adjusting the surface properties of nanoparticles to make nanoparticles adapt to the cement system, is a smart way to magnify the value of nano. Thirdly, nanoparticles utilized as a kind of surface-treatment agent is a burgeoning research direction, should be and will be the prior development direction
学术讨论
主办单位时间地点报告人报告主题
课题组汇报 2015年4月7日 江苏苏博特研发楼会议室 顾越 核壳纳米改性水泥基材料-阶段汇报
课题组汇报 2017年6月5日 江苏苏博特研发楼会议室 顾越 Advance in design of NS@PCE core-shell nanoparticles and its application in cementitious materials
课题组汇报 2015年10月10日 江苏苏博特研发楼会议室 顾越 核壳纳米二氧化硅构建及其对水泥基材料微结构影响-开题汇报
课题组汇报 2015年2月1日 江苏苏博特研发楼会议室 顾越 核壳纳米二氧化硅改性水泥基材料性能研究-年终汇报
东南大学材料科学与工程学院 2015年04月01日 东南大学材料A楼 Prof.BaiYun(UCL) 微波养护混凝土
东南大学材料科学与工程学院 2015年07月09日 东南大学材料A楼 席云平教授(美国科罗拉多大学) 绝缘与高强水泥基材料
UCLA 2015年11月6日 Boelter Hall Li zongjing(HKUST) Advance in concrete technology
UCLA 2016年7月29日 Boelter Hall Dannel Jansen Quantitative analysis of hydration products by In-sti XRD
     
学术会议
会议名称时间地点本人报告本人报告题目
University of Jinan 2017.5.20 Jinan Design of NS@PCE core-shell nanoparticles and its application in cementitious materials
University college London, UK 2017.09.11~2017.09.12 London, UK Effect of NS@PCE on water absorption of cementitious materials
     
代表作
论文名称
Synthesis of nanoSiO2@PCE core-shell nanoparticles and its effect on cement hydration at early age
Characterizing cement paste containing SRA modified nanoSiO2 and evaluating its strength development
Synthesis of SiO2-PCE Core-Shell Nanoparticles and its Modification Effects on Cement Hydration
Modifying Cement Hydration with NS@ PCE Core-Shell Nanoparticles
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
蒋林华 正高 教授 博导 河海大学
刘加平 正高 教授 博导 东南大学
高建明 正高 教授 博导 东南大学
蒋金洋 正高 教授 博导 东南大学
张云升 正高 教授 博导 东南大学
高玉峰 正高 教授 博导 河海大学
王立彬 正高 教授 硕导 南京林业大学
      
答辩秘书信息
姓名职称工作单位备注
佘伟 其他 讲师 东南大学