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钢渣存在安定性不良的问题,将钢渣应用于水稳层,会存在钢渣分布不均匀,使试样出现膨胀开裂的现象。通过研究发现,对钢渣基胶凝材料进行碳化处理可以提高其体积稳定性,粒径较细的钢渣能够增大碳化反应面积,有利于提高碳化程度。本文对≥200目钢渣进行碳化处理,研究碳化时间和碳化温度对预碳化钢渣基胶凝材料的体积稳定性影响,并对其碳化机理进行探究;与建筑再生骨料制备水稳层,对其进行无侧限抗压强度和抗冻性测试。结果表明,随着碳化时间的和温度增加,预碳化钢渣基胶凝材料压蒸膨胀率逐渐降低,活性先增高后降低。在常压下,碳化温度为60 ℃,碳化时间为1.5 h的钢渣基胶凝材料相对活性最高。 相似文献
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通过在硅酸盐水泥中加入不同掺量矿渣粉以及不同掺量和细度的钢渣粉,研究了矿渣和钢渣对水泥强度,孔结构和压蒸安定性的影响.实验结果表明:矿渣与熟料的比例是控制特定钢渣掺量的水泥28 d抗压强度的决定性因素,熟料和矿渣按照1:1混和的水泥具有最高强度,影响水泥28 d最高抗折强度则是矿渣掺量.加入钢渣增大了水泥的孔隙率,而加入矿渣则可以减少试块孔隙率;矿渣能够明显细化浆体的孔结构,钢渣矿渣水泥的28 d抗压强度主要受到大于50 nm孔隙含量的影响.水泥压蒸膨胀率随着钢渣掺量增加而增加,矿渣能够显著改善钢渣水泥的压蒸安定性. 相似文献
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探讨石灰石粉比表面积、矿物掺合料、早强剂、防水物质及CO2捕收剂对水泥-石灰石粉体系强度和碳化深度的影响。实验发现,硅灰替代20 kg/m3石灰石粉时28 d抗压强度达最高,为40 MPa,比空白高6 MPa,高比表面积(750 m3/kg)石灰石粉次之,为37 MPa,比空白高4 MPa,防水物质和过量硝酸钙会降低混凝土强度;掺入0.3%防水石蜡乳液可使体系碳化深度降至最低,达11 mm,比空白降低13 mm,掺入0.8%硝酸铁次之,碳化深度为13 mm,比空白降低11 mm,矿物掺合料替代石灰石粉不会有效降低碳化深度。因此可适度引入铁离子、防水组分或较高比表面积石灰石粉来提高该体系抗碳化性能。 相似文献
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《硅酸盐通报》2015,(Z1)
建筑材料中使用工业固体废弃物是节能减排的重要途径之一,本文采用钢渣和矿渣复合水泥作为胶凝材料制备水泥砂浆,并结合XRD、SEM和粒度分析等微观测试方法,对钢渣-矿渣复合胶凝材料活性及对砂浆性能的影响进行了试验研究。结果表明,当采用比表面积为400 m~2/kg和450 m~2/kg的钢渣,替代矿粉量达到10%时,钢渣-矿渣复合胶凝材料的活性可满足S95级矿粉活性的要求;钢渣的比表面积和掺量不同对砂浆的保水性影响不大,但对砂浆的稠度影响较大;为使砂浆强度满足使用要求,不同比表面积钢渣的最大掺量不宜超过30%;当采用钢渣作为活性矿物掺合料时,应采用与水泥和矿渣粒径相匹配的粒径分布,并通过试验确定掺量。 相似文献
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钢渣水化活性差,体积安定性不良限制了其作为辅助性胶凝材料的应用,但钢渣具有很好的碳酸化活性。本文在对钢渣进行预处理的过程中通过调整CO2浓度及碳酸化时间,调控钢渣的碳酸化程度,分析了碳酸化对钢渣微观结构及固碳效果的影响,同时评价了碳酸化钢渣作为辅助性胶凝材料的可行性。结果表明:含30%(质量分数)钢渣的水泥砂浆试块3、28 d抗压强度较未掺钢渣水泥砂浆分别降低了43.2%和30.0%,净浆试块经压蒸试验后由于膨胀过大而溃散;CO2浓度对钢渣的固碳量有显著的影响,高浓度(体积分数为99.9%)CO2进行碳化养护3 min时钢渣固碳量就达到了3.67%。钢渣的体积安定性与碳酸化程度呈正相关,而过度碳酸化处理会降低其水化活性,掺加30%(质量分数)碳酸化预处理3、10 min钢渣的砂浆3 d抗压强度较掺加30%原始钢渣的砂浆分别提高了28.3%和15.8%。 相似文献
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通过开展加速碳酸化将钢渣硬化为结构材料的研究,具有利用废渣和CO2废气的双重意义.针对钢渣碳酸化过程中可能存在的体积安定性问题,测定了不同细度、碳化反应时间对硬化试块空隙率、体积变化及力学强度的影响,利用质量损失计算了碳酸化后空隙率,利用XRD分析了产物的类别,利用SEM观察了硬化产物的显微形貌及生长位置,采用压蒸法对碳酸化后硬化钢渣试块的安定性进行了测试.结果表明了钢渣坯体碳酸化过程会降低块体的空隙率,钢渣在粉磨8 h,碳酸化7 d的条件下,总空隙率仅为16.67%,空隙率降低了10.17%,压蒸后,并未出现裂纹和损坏,体积安定性良好.同时钢渣中C2S、C3S、Ca(OH)2、f-CaO、MgO是易被碳化的矿物,而Ca2(Al,Fe)2O5、FeO矿物难以被碳化.分析指出,钢渣坯体中足够的空隙,以及CaCO3在空隙(非原地)中生长机制是碳酸化钢渣无体积安定性问题的根本原因. 相似文献
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为了促进不锈钢厂废渣的资源化利用,以红土镍矿酸性高炉渣和不锈钢渣为主要原料制备胶凝材料,研究机械活化和不锈钢渣质量掺量对矿渣胶凝材料性能的影响,并利用XRD、SEM对胶凝材料的水化产物及微观结构进行分析。结果表明,机械活化主要通过改变原料的比表面积和颗粒级配来影响胶凝材料性能,且矿渣中细颗粒占比是影响其胶凝活性的关键因素,适宜的球磨时间为45 min,此时矿渣比表面积达到524.66 m2/kg。不锈钢渣与酸性矿渣之间存在协同作用,当不锈钢渣质量掺量为20%时,胶砂试块3 d、7 d、28 d抗压强度分别为17.8 MPa、24.3 MPa 和34.8 MPa,抗折强度分别为4.5 MPa、6.2 MPa和6.8 MPa,达到P·S 32.5R矿渣硅酸盐水泥强度标准。不锈钢渣的掺入在水化早期和后期都促进钙矾石及C-S-H凝胶的生成,对胶砂试块各龄期强度都有促进作用,而未水化的钢渣细颗粒也起着微集料填充作用,有利于胶凝材料早期强度的提高。 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile
Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, 13C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc. 相似文献
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The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu3Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu3Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters. 相似文献
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《国际聚合物材料杂志》2012,61(1-4):113-122
Abstract Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed. 相似文献
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G. R. Hamed 《The Journal of Adhesion》1983,16(1):31-39
A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength. 相似文献
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Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method1 was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity. 相似文献
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责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体. 相似文献