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1.
混合材颗粒级配对水泥强度的影响   总被引:1,自引:0,他引:1  
研究了矿渣、粉煤灰经细磨处理后对水泥力学性能的影响.矿渣、粉煤灰经细磨处理后均能明显提高其水化活性,在纯熟料水泥中掺50%的细磨矿渣,其28天强度仍超过纯熟料水泥;纯熟料水泥中掺50%细磨粉煤灰,其强度比纯熟料水泥要低,但仍可达到GB1344-92标准425水泥强度要求.  相似文献   

2.
研究了矿渣、粉煤灰经细磨处理后对水泥力学性能的影响。矿渣、粉煤灰经细磨处理后均能明显提高其水化活性,在纯熟料水泥中掺50%的细磨矿渣,其28天强度仍超过纯熟料水泥;纯熟料水泥中掺50%细磨粉煤灰,其强度比纯熟料水泥要低,但仍可达到GB1344-92标准425水泥强度要求。  相似文献   

3.
粉煤灰-水泥中掺氢氧化钠能够增加水泥早期强度,本次试验通过测定3 d、28 d龄期的胶砂强度值;并分析得出氢氧化钠最佳掺量分别为5%和6%;粉煤灰的最佳为10%;相对与基准组强度提高率最高的粉煤灰掺量分别为20%和30%。其次,将3 d龄期的强度提高率和28 d比较,得出龄期对强度发展的影响;同时,利用有限元方法模拟混凝土试件单轴抗压的受压破坏过程;并将数值模拟结果与物理实验对照,精度基本满足要求,其方法为混凝土的研究提供新思路。  相似文献   

4.
通过对1d龄期的再生混凝土拉伸徐变试件进行单轴拉伸,研究再生粗骨料、单掺粉煤灰和复掺粉煤灰加矿渣对再生混凝土早龄期各类拉伸徐变性能的影响. 结果表明:再生混凝土拉伸徐变性能与普通混凝土类似,呈现早期发展快、后期发展慢的规律;掺入70%再生粗骨料导致再生混凝土各类拉伸徐变增加,拉伸总徐变增幅为8.0%;单掺粉煤灰和复掺粉煤灰加矿渣均导致再生混凝土各类拉伸徐变增加,30%~60%粉煤灰掺量的再生混凝土拉伸总徐变增幅为8.5%~32.5%,30%~60%粉煤灰加矿渣复掺量的再生混凝土拉伸总徐变增幅为2.6%~21.7%;相较于单掺粉煤灰,复掺粉煤灰加矿渣的再生混凝土的拉伸徐变增幅较低.  相似文献   

5.
粉煤灰、矿渣复配组成碱激发复合水泥可以改善单一组分碱激发水泥的性能劣势。为了研究不同碱当量、不同粉煤灰和矿渣掺量对碱激发粉煤灰-矿渣砂浆力学性能、干燥收缩及微观结构特性的影响,采用抗压、抗折强度试验、吸水率试验、干燥收缩试验、微观扫描电子显微镜(scanning electron microscope, SEM)及傅里叶红外光谱(Fourier transform infrared spectrometer, FTIR)试验进行表征。结果表明:3、7、28 d龄期时,随着碱当量和矿渣掺量增加,粉煤灰-矿渣砂浆抗压、抗折强度呈逐渐增加趋势,吸水率和干燥收缩率呈逐渐下降趋势。其中龄期为28 d,碱当量为6%、矿渣掺量为100%时,碱激发粉煤灰-矿渣砂浆抗压强度达到峰值110.84 MPa,抗折强度达到峰值10.77 MPa,吸水率最小,为1.2%,与4%的粉煤灰-矿渣砂浆相比,碱当量为6%的砂浆干燥收缩率均减少10%以上。由微观分析知,粉煤灰-矿渣砂浆在碱激发作用下水化产物主要为铝硅酸盐凝胶和水化硅酸钙凝胶,粉煤灰掺量越大,凝胶结晶度越低。碱当量越大,体系水化产物数量越多,结构越密实。  相似文献   

6.
引入掺和料是提高无砟轨枕混凝土的脱模强度、后期力学性能及耐久性的重要措施之一。借助单纯重心设计法,采用矿渣粉、粉煤灰与高活性粉体A制备高活性复合掺和料,研究复合掺和料组成对早期活性指数、水化热以及混凝土抗压强度的影响。结果表明:复合掺合料的组成对其活性指数影响较大,并体现出明显的复合增强效应;高活性粉体A与矿渣粉二元复掺的混凝土1 d与28 d活性指数均达118%; 3 d龄期后矿渣粉放热增加,而粉煤灰水化放热一直较低,矿渣粉或粉煤灰与高活性粉体A二元复掺时浆体1 d水化放热差别很小;三元复掺混凝土的复合增强效应优于二元复掺,三元复掺混凝土28 d与60 d抗压强度分别达68. 6 MPa和79. 6 MPa。  相似文献   

7.
复合胶凝材料组成与混凝土抗压强度定量关系研究   总被引:1,自引:0,他引:1  
通过单纯形重心设计方法得出了水泥一磨细矿渣微粉一超细粉煤灰三元复合胶凝材料组成与各龄期混凝土抗压强度的定量数学解析式,其对混凝土强度的预测精度基本可控制在5%的相对误差范围内.不同龄期三元系统的等强线变化揭示了3d和28d时,复合胶凝材料各组分对强度的贡献按水泥、磨细矿渣微粉、超细粉煤灰的顺序降低,180d时则按水泥、超细粉煤灰、磨细矿渣微粉的顺序降低,从而揭示了磨细矿渣微粉与超细粉煤灰复合对混凝土早期和后期强度存在互补效应.  相似文献   

8.
掺复合微细集料配制高强混凝土的研究   总被引:1,自引:0,他引:1  
研究了掺高效减水剂与各种微细集料(粉煤灰、细磨沸石)配制高强泵送混凝土的方法和机理.结果表明,掺加上述微细集料可以有效地改善混凝土中水泥浆及界面结构,显著提高混凝土强度.用Ⅱ级粉煤灰与细磨沸石复合作微细集料,混凝土中水泥用量为460kg·m~(-3)时,28d混凝土强度可达75.5MPa.  相似文献   

9.
为研究粉煤灰-矿粉-水泥三元胶凝材料对混凝土抗压强度的影响,测试混凝土标准养护3、7、14、28和56 d龄期的抗压强度,分析凝土抗压强度与胶凝材料各组分的关系。实验结果表明,混凝土抗压强度与粉煤灰-矿粉-水泥三元体系组分的掺量比例有密切关系。粉煤灰和矿粉双掺时,由于粒径不同会相互填充,从而产生超叠加效应,使掺加粉煤灰和矿粉的混凝土抗压强度得到明显改善。水泥、矿粉、水泥及粉煤灰的组合、粉煤灰和矿粉的组合对混凝土的抗压强度有增强作用,其中粉煤灰和矿粉的协同效应对混凝土抗压强度增强最为明显。随着龄期增加,粉煤灰和矿粉的协同效应对混凝土抗压强度的增强作用逐渐减弱,与28 d抗压强度相比,其对56 d抗压强度贡献降低了55.9%;粉煤灰及水泥-粉煤灰-矿粉的三元组合对混凝土抗压强度的影响逐渐降低,与28 d抗压强度相比,粉煤灰及水泥-粉煤灰-矿粉的三元组合对56 d抗压强度的降低效应分别减少了40.9%和67.3%。  相似文献   

10.
龄期对不同掺料相变混凝土力学性能影响试验与分析   总被引:1,自引:0,他引:1  
为制备具有一定强度的掺料相变混凝土,通过分别对不同标准龄期养护下的同一配合比不同掺料的相变混凝土立方体试件进行了抗压与劈裂抗拉强度试验与分析。试验结果表明,除3 d龄期外,单掺硅粉相变混凝土在不同龄期下的抗压能力均高于其他掺料相变混凝土;单掺粉煤灰相变混凝土在不同龄期下的抗拉能力均低于其他掺料相变混凝土;双掺粉煤灰与硅粉的相变混凝土直到龄期达到90d的时候,才会到达相变储能组的强度。  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.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  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.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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