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1.
基于以废治废有效利用大掺量粉煤灰治理淤泥的思路,使用水泥和生石灰作为粉煤灰的激发剂,同时使用高吸水树脂内供水进行固化土内养护,进行固化土无侧限抗压强度试验和含水率试验.水泥加高吸水树脂、水泥加粉煤灰及水泥加生石灰双掺固化试验发现,各掺量下固化土的强度随龄期的增长而增长,在水泥掺入比一定时各种固化材料存在最佳掺量;以此为基础的四种材料的正交试验得出了固化淤泥的最佳的配比组合并分析固化机制,可以为低掺量水泥处理高含水率疏浚淤泥的实际工程提供参考.含水率试验得出粉煤灰和生石灰能快速降低固化土的含水率,高吸水树脂能够延缓固化土含水率的降低,能够通过内供水的方式保证水化反应环境,继而促使水化反应更大程度地进行.  相似文献   

2.
不同物料中f-CaO的水化活性、膨胀特性及其对硬化水泥浆体强度的影响各不相同.高钙粉煤灰中的f-CaO水化最快,试样膨胀主要发生在7天以内;水泥熟料中的次之;钢渣中的水化最慢,试样膨胀稳定期超过56天.掺高f-CaO熟料的试样强度最高;掺高钙粉煤灰者次之;掺钢渣者强度最低.  相似文献   

3.
自养护作用下的高性能混凝土抗冻与抗渗性能   总被引:2,自引:0,他引:2  
为探讨超强吸水剂(SAP)对高性能混凝土的自养护效果,研究了不同环境下掺SAP的高性能混凝土的抗冻与抗渗性能。在新拌混凝土中掺入不同数量的SAP,将试样置于35℃、相对湿度为10%以及5℃、相对湿度65%的环境中养护56 d,研究中进行混凝土抗冻与抗渗试验。结果表明,与未掺SAP的混凝土相比较,掺SAP的高性能混凝土的抗冻与抗渗性能大幅度提高,其性能随着SAP掺量的不同而各异,存在一个最优的掺量;SAP可作为高性能混凝土的自养护剂。  相似文献   

4.
为研究额外引水条件与高吸水性树脂(super-absorbent polymer,SAP)掺加方式对砂浆收缩和孔结构的影响,分别在总水胶比固定和稠度固定的条件下开展砂浆性能试验.以SAP吸水试验和砂浆稠度测试为基础,探讨干粉SAP和预饱水SAP在水泥基材料中吸液性能的差异,然后通过体积稳定性试验、压汞试验和扫描电镜观察,评价不同额外引水条件和SAP掺加方式对砂浆自收缩、干燥收缩和孔结构参数影响的差异.结果表明:在砂浆基体中,以干粉形式直接掺加的SAP比经过预吸水处理的SAP吸液性能强30%~50%; SAP能有效降低砂浆的自收缩,且SAP以干粉形式直接掺加时对自收缩的抑制作用更显著;额外引水可略微降低早期的干燥收缩,但是易引起砂浆后期干燥收缩变大;掺加SAP能细化砂浆孔结构,降低50~1 000 nm之间的大毛细孔数量,增加小于50 nm的小毛细孔数量,且在同掺量条件下干粉SAP的细化作用更显著.  相似文献   

5.
预合成不同龄期和不同细度的5Mg(OH)2·MgSO4·7H2O(517晶相),实验研究517晶相加入量对MOS水泥抗压强度、耐水性能的影响,利用XRD、SEM、MIP等对试样矿相组成、微观形貌及孔隙率进行分析。实验结果表明,掺加一定量预合成517晶相有利于提高MOS试样的抗压强度。掺加养护7 d的517晶相有利于早期强度的提升,添加20%的试样1 d强度达到29.5 MPa,空白试样提高34%;掺加养护28 d的517晶相有利于耐水性能的提高。掺加10%养护28 d的中位径为7μm的517晶相,MOS试样的软化系数可达到1.02。预合成517晶种可以促进MOS体系中517晶相的原位生长,抑制体系内剩余MgO水化,同时基体内形成较多的凝胶相,使试样的总孔隙率降低,基体致密度增加,进而提高试样的抗压强度及耐水性。  相似文献   

6.
不同养护制度下混合水泥反应程度的研究   总被引:2,自引:0,他引:2  
通过测试各混合水泥试样结合水量和掺合料反应程度.研究了不同养护制度对混合水泥水化程度的影响。研究结果表明,早期较高的养护温度可加快混合水泥的反应速率,提高其反应程度.但对后期标养条件下混合水泥反应程度的增长有影响;早期低温养护情况下混合水泥的水化受到抑制。其反应程度相当低,但后期标养条件下有一定增长。养护温度升高有利于混合水泥中掺合料反应程度的提高.但在后期长时间标养条件下,奇试样中掺合料反应程度趋于接近。  相似文献   

7.
针对普通水泥基材料存在早期强度低、抗变形能力弱等问题,通过纳米硅溶胶对水泥基材料进行改性,采用电液伺服万能试验机、X射线衍射及扫描电镜等手段对纳米硅溶胶改性不同水灰比水泥基材料的流动性、结石率、单轴抗压强度、弹性模量、水化产物及微观形貌进行研究。结果表明:硅溶胶掺量在0.5%以内、水灰比小于1.0时可显著提高水泥浆液的流动性,最大提高20.24%;结石率随着纳米硅溶胶掺量的增加而增大,且硅溶胶对水灰比大于0.7浆液的结石率提高明显,最大提高24.49%;当硅溶胶掺量为2%时,结石体的抗压强度增幅最大且随着养护龄期的增加,硅溶胶对试样强度的增幅效果逐渐减弱;纳米硅溶胶的掺入促进水泥基早期的水化反应,与水化产物反应生成水化硅酸钙凝胶(C—S—H)并使微观形貌更加致密,使结石体的早期抗压强度及弹性模量显著提高;纳米硅溶胶通过缩短诱导期以及在颗粒空隙中为C—S—H提供成核位点促进水化反应,提高水泥基材料性能。  相似文献   

8.
多功能水泥复合助磨剂研究   总被引:2,自引:0,他引:2  
采用有机-无机复合技术途径研究具有助磨、增强、减水等作用的多功能水泥复合助磨剂.结果表明,采用复合助磨剂比采用单组分助磨剂明显提高了水泥的筛余细度和比表面积,改善了水泥粉体的流动性;在掺量小于1%的前提下,有效提高了水泥的强度.对水泥水化样的TG—DTA及SEM分析表明,掺入多功能复合助磨剂后,大幅度提高了水泥的水化速率,促进更多水化产物的生成,使硬化浆体结构更加致密.  相似文献   

9.
就道路水泥混凝土中掺入粉煤灰后强度形成机理及物理力学性能变化作初步探索分析.通过试验分析表明:在道路水泥混凝土中可以采用掺入部份粉煤灰代替水泥,它能保持原有强度,其原因在于粉煤灰所含的SiO2成份受到水泥水化水解所产生的Ca(OH)2中活性CaO的激发作用而与其发生化学反应形成硅酸盐含水结晶,代替被减少的水泥作用.但当粉煤灰掺加量超过一定界限则水泥混凝土强度下降.其合理的掺量为水泥用量的15%(内掺)  相似文献   

10.
利用DTA、XRD、IR、化学结合水和Ca(OH)2生成量测定等方法,研究了煅烧石膏、二水石膏对硅酸盐水泥早期水化过程的影响。结果表明:在水化龄期相同时,掺煅烧石膏水泥浆体中水化产物同掺二水石膏相比,Ca(OH)2生成量大;在一天前无心生成;结合水量在一天前前者高于后者,而一天后则相反。指出了煅烧石膏提高水泥强度的机理在于:由于煅烧石膏的溶解速度较低,在水泥水化初期(1d前),存在于水泥中的铝酸盐相不能形成心,从而减缓了AFt对水泥水化的延缓作用,加速了整个熟料矿物相的水化,提高了水泥的强度。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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