化学激发酸性矿渣粉胶砂性能试验研究

以28天最优配方激发酸性矿渣粉为胶凝材料进行试验,分析了质量浓度、灰砂比、减水剂掺量、搅拌时间4个因素对砂浆流动度、失水率、干缩率、抗压强度的影响规律,并且针对灰砂比这一因素将水泥与矿渣粉胶凝材料浆液性能进行了对比。最后选取了合适的比例进行正交试验来优化各因素组合,使砂浆综合性能达到最优。     

粉磨方式对矿渣-粉煤灰基复合胶凝材料的影响

<正>我国每年排放的矿渣、粉煤灰固态工业废弃物达数亿吨,大部分矿渣、粉煤灰具有潜在的活性和胶凝性,经过激发活化可以变成极好的活性矿物掺和料或者胶凝材料。本实验采用不同粉磨方式对矿渣-粉煤灰基胶凝材料的影响进行研究,拟探寻出一种最佳的粉磨矿渣-粉煤灰基胶凝材料的工艺。     

矿渣粉加固粉土的理论分析及路用性能研究

提出了矿渣粉加固粉土的相关理论。将矿渣粉在加固土中的作用归结为火山灰胶凝效应和微集料填充效应,而火山灰胶凝效应又可进一步归结为水化作用、激发作用和离子交换作用;认为微集料填充效应与矿渣粉细度极为相关;用框图归纳了矿渣粉加固土的两种作用效应。进行了矿渣粉、石灰粉加固土无侧限饱水抗压强度、水稳定性、冻稳定性、温度收缩和干燥收缩等路用性能试验,并进行比较。结果表明,矿渣粉加固土所测路用性能指标优于石灰粉加固土。为工程应用提供了试验依据。     

矿渣胶凝材料固化软土的力学性状及机制

利用矿渣胶凝材料固化软土,既可利用工业废渣,又能减少水泥的用量。以矿渣胶凝材料固化黏土、砂土二种软土。发现矿渣胶凝材料加固软土的效果远好于水泥、石灰,其9 %掺量的固化土28 d的无侧限强度达到2.0 MPa以上,普遍高于15 %掺量的水泥固化土,且其28 d固化土的软化系数普遍高于90 %以上,固化黏土后CBR值远高于同掺量的石灰固化土。X衍射结构分析表明,矿渣胶凝材料水化时产生的高强难溶的矿物晶体是其固化软土效果好的主要原因。因此,矿渣胶凝材料是一种性能优异的软土加固材料。     

流态地聚物固化土强度特性及其强度预测

地聚物胶凝材料能够替代水泥基胶凝材料作为固化剂应用于狭窄肥槽回填等工程问题中,有效降低水泥生产过程中的污染及能耗,但目前对于流态地聚物固化土胶凝材料的研究较少。采用3种新型绿色胶凝材料联合碱激发剂固化工程渣土形成流态地聚物固化土,通过对比其无侧限抗压强度,探究每种胶凝材料对于固化土强度特性的影响,同时建立强度预测模型,分析不同因素对于强度的影响程度。研究结果表明：固化土的强度随着碱激发剂模数的增加先提高后降低;固化土强度随着高炉矿渣（GGBS）、粉煤灰、稻壳灰掺量的增加均呈上升趋势,随着稻壳灰粒径的增长呈下降趋势;碱激发剂模数增至1.2、GGBS掺量增至10%、粉煤灰掺量增至8%和稻壳灰掺量增至11%时,固化土强度提升最为显著;强度预测模型预测结果的平均相对误差仅为5.57%,预测结果较为精准;预测模型中各层权值的计算结果表明养护龄期对于固化土强度影响最大,稻壳灰粒径影响程度最小。研究结果可以为固化土在实际工程的应用提供理论支持。     

建筑文物中石灰质修复材料的研制

为实现对建筑文物的“原真性”修复,利用X 射线衍射仪和激光粒度分布仪测定了历史建筑物中原胶凝材料矿物的组成和结构,并采用湿化学方法对原勾缝剂进行物料组成的复原,证明历史勾缝剂材料主要为石灰基材料。在复原的原胶凝剂材料配方的基础上分别加入活性火山灰、木质纤维素、分散性胶粉、早强剂和减水剂等对勾缝剂进行性能改进。经反复试验优选出了修复用勾缝剂材料的配方,并测试了试样的各项物理性能。结果表明,修复材料抗压强度达14. 47 MPa,饱和吸水率为 27. 07%,体积变化率＜ 1%,冻融循环4 次不变,证明改性后勾缝剂材料可以满足修复胶凝材料的性能要求。     

湖底淤泥固化土的环境耐久性研究

为了评价淤泥固化土的环境耐久性,采用矿渣体系的碱激发胶凝材料(矿渣粉、偏高岭土、石灰和水玻璃)和普通硅酸盐水泥为固化剂,通过开展无侧限抗压、冻融循环、Na2SO4及NaCl浸泡侵蚀、扫描电镜和EDS-Mapping试验,分析了侵蚀环境下固化淤泥土的典型水化产物、强度演变规律、质量损失率和微观结构特征,结果表明,碱激发固化淤泥内部生成的水化硅铝酸钠凝胶(N-A-S-H)能有效提高强度,但是冻融循环和浸泡侵蚀均会导致固化土强度劣化;水泥固化淤泥受硫酸盐侵蚀后,钙矾石会呈现簇状发展而产生膨胀开裂,导致强度下降;碱激发固化剂的抗氯离子能力优于硫酸根离子,综合环境耐久性优于普通硅酸盐水泥。     

粉煤灰基地聚物加固土的强度及抗冻融性能试验研究

粉煤灰基地聚物作为一种低碳胶凝材料,在地基处理中的应用越来越受到关注。但是目前关于碱激发胶凝材料加固土在冻融极端气候条件下的工程特性尚不清楚,有必要进一步开展冻融循环条件下加固土的强度、变形特征及其影响因素研究。通过室内试验研究了原材料硅铝比、碱激发剂模数及碱溶液浓度对粉煤灰基地聚物固化土的强度与抗冻融性能的影响及微观...     

碱激发材料固化低液限粉黏土路用性能及抗冻融特性研究

以伊犁地区S315线蜂场至尼勒克段低液限粉黏土为研究对象,以碱激发材料为固化剂,对粉质黏土和其固化土开展了路用性能指标试验与冻融循环试验,并利用电镜扫描试验(SEM)与X射线衍射试验(XRD)研究了固化土的微观特征,探讨了碱激发材料对粉质黏土路用性能指标与抗冻融特性的影响.试验结果表明,固化土的无侧限抗压强度与抗剪强度...     

激发剂对矿渣胶凝材料性能影响研究

目前国内外学者对矿渣激发剂做了较多的研究(Tatiana Bakharev等,1999;赵永林等,2007),在这些激发剂中以水玻璃的激发效果较为显著,但由于水玻璃是液体,使用起来十分不便,且凝结时间难以控制。     

湖泊底泥改性固化的强度特性和微观结构

将灰渣胶凝材料作为改性剂应用于湖泊环境疏浚底泥的固化处理,研究了改性淤泥的强度特性,探讨灰渣胶凝材料对淤泥的改性机理。改性淤泥的抗压强度试验结果表明,当灰渣胶凝材料质量掺入比为5 %时,能够显著提高改性淤泥的各个龄期强度;当掺入质量比为12.5 %时,28天强度可以达到1.55 MPa。改性淤泥的早期强度较高,后期强度能持续增长,同时具有良好的耐水浸泡性能。SEM分析表明,灰渣胶凝材料能与底泥颗粒中的活性物质发生火山灰反应,形成高强难溶的胶结物,使改性淤泥中大孔隙数量减少,改善了淤泥土颗粒之间的胶结性能。这说明灰渣胶凝材料是一种性能优异的底泥改性材料。     

利用液态磷渣制备乳浊玻璃

为实现炼磷排放的高温液态磷渣的热能、物质的同步回收利用, 并消除其环境污染问题, 通过现场试验, 以高温液态磷渣为主要原料, 直接与16.5%的石英粉和8.5%的高岭土热配合, 再经1450℃熔炼、浇铸成型和850℃乳化热处理, 制得了乳浊玻璃板材.磷渣乳浊玻璃的抗折强度为43.68MPa, 耐酸性为0.51%, 耐碱性为0.04%, 能满足建筑装饰材料的质量要求.ESEM、XRD和EDS分析结果共同表明, 母玻璃的乳浊机理在于主体玻璃中析出了富Ca元素的粒径为0.1~0.4μm的非晶质球形颗粒.由于高温液态磷渣掺量高达75%, 改性剂掺量低且成本低廉, 生产线易于配置, 本研究具有较高的工业化生产可行性、较佳的经济效益和应用前景.      

铁晶砂胶结新型岩土相似材料的研制及其应用

根据地质力学模型试验的相似原理,经过大量力学试验,研制出一种新型铁晶砂胶结岩土相似材料。该材料由铁矿粉、重晶石粉、石英砂、石膏粉和松香酒精溶液按规定配比均匀拌和压实而成,其中铁矿粉、重晶石粉和石英砂作为主料,松香酒精溶液作为胶结剂,石膏粉作为调节剂。材料力学参数测试表明：该材料具有重度高、力学参数变化范围广、性能稳定、价格低廉、干燥快速、制作工艺简单、无毒无害等显著优点,可用来模拟从软岩到硬岩的大部分岩体材料。将铁晶砂胶结岩土相似材料应用于沪―蓉―西高速公路大型分岔隧道三维地质力学模型试验研究,有效地揭示了分岔隧道围岩的力学变形特性。     

Early Intervention on the Properties of Steel Slag at High Temperature by Modifier Compound with Tailings: A Feasible Way for Comprehensive Utilization of Solid Wastes

Steel slag, a by-product of the steel production industry reaches 10%–15% of crude steel output (Motz and Geiseler, 2001). Their main application lies in the field of building materials due to some containing cementitious components, such as dicalcium silicate (C2S) and tricalcium silicate (C3S) (Waligora et al., 2010). However, blended cements with steelmaking slag show low early hydration activity, low compressive strength and bad durability because steel slag generates above 1600 ℃ with the tense and large grain size crystals, consisting of low content of C2S and C3S and high proportions of f-CaO and f-MgO compared with cement clinker.     

Influence of Water Content on Mechanical Properties of Improved Clayey Soil Using Steel Slag

The use of steel slag fines has been fully investigated and developed as it has similar chemical composition and mineralogy to that of Portland cement. Researchers from home and abroad have done lots of research on steel slag, such as its production, processing, properties, mechanical behavior, cementitious property and so on. This paper describes influence of water content on mechanical properties of improved clayey soil using steel slag and a series of tri-axial compression tests are carried out to study the influence of water content to the admixture of clayey soils and steel slag. Through the test data statistics and analysis, the basic rules of the mechanical properties of these mixed soils were gotten, especially, the optimum steel slag and water content. Through tri-axial compression tests, there are several kinds of specimen failure forms in different conditions of steel slag and water content. The stiffness of steel slag is larger than clayey soil, so the specimen with steel slag would break with an oblique angle whereas the clayey soil specimen would be compressed. Drawn from the experiment, while water content increases, cohesion c increases and internal friction angel φ decreases; however, in general, the maximum stress difference firstly increases, and then decreases. Under the same water content, with the curing period and steel slag content increase, cohesion c increases, internal friction angel φ decreases, however, the stress difference increases. By analyzing the specimen failure forms and the relations of stress difference and axial strain, the relations between stress difference max (σ₁ ? σ₃) and steel slag content and relations between the secant modulus E₅₀ and steel slag content are gotten. It is concluded that when the water content is about 18 % and steel slag content is about 30 %, the stress difference and secant modulus E₅₀ is larger than other cases. Therefore, in soft soil foundation treatment, such steel slag and water content could be chosen in order that the soil strength would be improved. So, judging from the results, the foundation settlement will be reduced by mixing appropriate steel slag and water content.     

Utilization of Basic Oxygen Furnace (BOF) slag in the production of a hydraulic cement binder

Basic Oxygen Furnace (BOF) slag is a major waste product generated during the steelmaking process. In India and in most industrial countries, the use of BOF slag as a road ballast and land filler has had a very long history. This being a low end use, a study was conducted to examine the possibility of converting the slag into a hydraulic binder. This paper describes the effect of cooling rate on mineralogy and cementing characteristics of normal BOF slag as well as iron oxide-devoid BOF slag. Specifically, the mineralogy and compressive strengths of heat-treated slags were compared with a conventional ordinary Portland cement. It was found that the slowly cooled slags did not show any cementing properties. The iron oxide-devoid slag, on slow cooling, disintegrated into fine powder. The water-cured cubic specimens of quenched slag products were tested for their compressive strengths. The cementing properties of the quenched slag products were improved by formation of hydraulic phases and showed considerable strength after 28 days of water curing.