【作者】 罗忠涛；

【导师】 马保国；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2010， 博士

【摘要】 目前,全球每年水泥工业生产所排放的CO2量与混凝土70年龄期对CO2的自然吸收固化量比例为9.43左右,水泥工业体系的碳当量传递链已完全失衡。同时,我国工业固体废弃物综合利用率不到40%,累积固体废弃物已达70亿吨,占地约7万Km2。基础建设与社会经济发展迫切需要使之成为水泥基材料中能够调节性能的辅助性材料,以减少水泥工业生产过程中的资源消耗与污染排放。本研究工作来源于(国家973计划2009CB623201-01)“现代混凝土胶凝浆体微结构形成机理”与(国家科技支撑计划2006BAF02A24)“高性能水泥绿色制造工艺和装备”。以目前应用最广泛的粉煤灰及矿渣作为代表性的硅铝质胶凝材料,探明其在多因素环境下的化学活性特征及其水化机理,通过物理化学手段对其进行表面结构解聚以增强其化学活性,研究硅铝质胶凝材料之间的协同效应匹配关系,进而通过多因素的优化配伍(协同效应、活性激发技术及特殊组分微调等)进行满足工业近零排放原则的制备关键技术设计。1.采用Ka-ICP法、非蒸发水量及反应程度等评价方法,系统研究在水热碱性环境、水泥水化环境下粉煤灰、合金矿渣等硅铝质胶凝材料活性,建立了硅铝质胶凝材料化学活性综合评价体系。(1)对Kα法环境下的粉煤灰进行化学反应进程模拟,水热碱性环境下的反应初期,网状聚合体与Ca(OH)2反应形成CSH单层膜或CH-CSH双层膜附着于颗粒表面。随着龄期的延续,反应层逐渐深入,此过程中反应界面会出现惰性莫来石及/或新生矿物沸石等惰性物质阻碍反应的进行,而易反应区域会形成溶蚀活化点促进反应介质的继续反应。随着反应深度的加深,溶蚀活化点在反应后期进一步扩展形成溶蚀反应区域,粉煤灰玻璃体中的大部分活性硅铝质参与反应,只剩下由惰性莫来石及/或新生矿物沸石形成的镂空状搭接结构。(2)粉煤灰+水泥二元体系中存在一种平衡关系,即水泥水化的Ca(OH)2生成量与粉煤灰化学反应的Ca(OH)2消耗量。并且粉煤灰化学反应所需的Ca(OH)2浓度随其在各反应阶段的表面结构活性及外层包裹膜厚度的不同而不同,基本随厚度增加呈现递增的趋势。2.提出了硅铝质胶凝材料高温增钙改性的优化方法,并采用NMR、FTIR等方法探讨了改性粉煤灰硅铝网络结构的解聚机理与规律；结果表明高温增钙使部分Si-O键断裂,其断裂导致高配位的网络中间体Al及Ca较多渗入,从而使网络结构部分强峰的化学位移向低场移动,化学活性得到明显提高。(1)最终优化的高温增钙粉煤灰配比为CFA-4-1200℃,即81.0%LCFA1+15.0%CaO+3.0%石膏+1.0%萤石,温度制度为1200℃下0.5h。(2)29Si NMR结果分析发现相对于原状粉煤灰,经过高温增钙改性后的粉煤灰其强峰线位移朝正值方向移动,呈现出由高场的集中向低场的分散趋势,说明其网络结构聚合度降低。3.提出了化学活性反应时效性贡献率的概念,揭示了硅铝质胶凝材料各时间段反应效率主导与辅助作用的转变规律。研究了改性硅铝质胶凝材料在水泥基材料中的水化机理及多元体系下的协同效应,并探讨了多元复合体系的次第水化理论。4.提出了多元体系高性能复合胶凝材料的设计方法,系统研究了高性能复合胶凝材料的水化热、体积变形、开裂敏感性及抗硫酸盐侵蚀等性能。结合多元体系协同效应的研究制备高性能复合胶凝材料,实现固体废弃物45%掺量下,其1d水化热下降30%以上,开裂敏感性方面的初始开裂时间相对基准样延长175%以上,28d的线性收缩率相对基准样降低25%以上,抗硫酸盐侵蚀性能相比于基准样提高45%以上(按ASTM C1012-95A标准)。更多还原

【Abstract】 At present, the rate of CO2 emission quantity by the whole world cement industry production to CO2 absorption quantity by building concretes in 70 years is about 9.43, so the cement industry system’s carbon equivalent transmission chain has already been completely unbalanced. And industry solid rejectamenta synthesis using rate in our country is less than 40%, has accumulated to 7,000 million ton and occupied a land area for approximately 70,000 square kilometers. The construction of a resource-economical and environment-friendly society need to make it to become the control characteristic cement material and reduce the resources consumption and the pollution emissions in the cement industry production process.This research work originates in (973 Program. Project 2009CB623201) and (National Key Technology R&D Program. Project 2006BAF02A24). Us the most widespread fly ash and slag by at present as the representative inorganic silicon-aluminum character material, verify its chemical activity characteristic and the hydration mechanism under the multi-factor environment, carry on the surface texture depolymerization through the physical chemistry method to strengthen its chemical activity, study the cooperative effect match relations among inorganic silicon-aluminum character materials, then carry on the preparation key technologies satisfying the industry near zero emissions principle design by cooperative effect, active stimulation technology, special component optimization and so on.1. The synthesis chemical activity appraisal system is established for the first time, through the strength performance, the non-evaporation water quantity, the reaction degree and the K(?)-ICP performance of fly ash, slag in hydrothermal and alkaline environment.(1) Fly ash granule react with Ca(OH)2 and generate CSH monolayer film or CSH double deck film at initial stage which adhere to the granule surface. The formation of reactant reduces the increase speed of Ka value at initial stage. The area where is easy to react forms activation point to promote reaction medium to react continually. activation point enlarges more at later period, and most active SiO2,Al2O3 in fly ash will react completely, and the inert mullite and newborn mineral-zeolite which doesn’t react in this process will form joining structure with hollow shape.(2) In the fly ash and cement binary system, there is one kind of balanced relations between production quantity of cement hydration Ca(OH)2 and consumption quantity of fly ash chemical reaction Ca(OH)2. And the difference of Ca(OH)2 density used in fly ash chemical reaction is along with its wraps film thickness in each reaction stage’s surface texture and activity, basically presents the increasing tendency with its film thickness.2. Has developed research on the superficial depolymerization and the chemical activity stimulation effect of inorganic silicon-aluminum character material stimulation system under the different hot historical.(1) Propose the optimized way in high temperature increasing the calcium environment:Firstly, use the CaO-SiO2-Al2O3 three phase diagram analyses and the free calcium oxide test to determine probably the calcium mixed quantity and temperature sector, then make sure optimize allocated proportion of calcareous (CaO) using the high temperature microscope.And through 29Si/27Al NMR, FTIR and so on to carry on the analysis the modified fly ash silicon-aluminum network structure, and use the chemical activity appraisal system to conduct the active characteristic analytical study. And the optimal allocated proportion is CFA-4-1200℃, namely 81.0%LCFA1+15.0%CaO+3.0% gypsum+1.0% fluorite, temperature system is under 1200℃for 0.5h.(2) By 29Si NMR result analysis, comparing to original condition FA, the strong crest lines of modified fly ash by high temperature displacement toward plus direction, present the tendency of the high field centralism to the low field scattered, indicates that its network architecture polymerization degree has reduced. Unify 27Al NMR to carry on the mechanism analysis, in the high temperature increasing calcium environment, calcareous is extremely easy to invade in the middle of the silica polymerization structure and makes the network architecture be not steady, and the Si-O key’s break will make the high coordinate network intermediate Al and some Ca permeate, thus cause the strong peak chemical in the network architecture shift to the low field, and the chemical activity of modified fly ash could be enhanced inevitably.3. Introduce into the concept about chemical activity response time-limited contribution rate for the first time, and there are mainly two understanding points to the grading hydration theory:Firstly, this theory mainly aims at the chemical activity to respond of compound system various components without considering other effects, such as micro aggregate effect, shape effect and so on; Secondly, reasonable understanding about the grading should be its time-limited contribution rate in certain order, namely various components hydration response has been existing, but there is certain order or overlapping superposition on response efficiency in various time section.4. Through the hydration heat, the volumetric deformation, the dehiscence sensitivity and the anti-sulfate corrosion test, carry on the multi-dimensional system high performance compound cementious material design and the performance study.Unify the multi-dimensional system cooperative effect the research preparation high performance compound cementious material to set 45% mixture rate of solid rejectamenta. its 1d hydration heat drops above 30%, the dehiscence sensitive aspect’s initial dehiscence time lengthens above 175% to datum type, the 28d linear shrinkage reduces above 25% to datum type, the anti-sulfate corrosion performance enhances above 45% to the datum type (according to ASTM the C1012-95A standard).更多还原