共查询到20条相似文献，搜索用时 46 毫秒
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通过设计在不同配合比的人工砂和天然砂试验,定性的找到了不同配比与人工砂混凝土抗压强度及干缩性的关系曲线。实验研究结果表明,随着人工砂掺量的增加,人工砂混凝土抗压性能有明显的提高,但是其干缩性能越差。因此,人工砂与天然砂的配合比为3:2时,C40人工砂混凝土有较好的抗压性能和干缩性能,能够达到相应规范的硬性指标。 相似文献
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以温度、聚丙烯纤维(PP纤维)掺量为试验参数,通过试验研究PP纤维掺量对高强人工砂混凝土抗火性能的影响。结果表明:在高强人工砂混凝土中掺入PP纤维可以显著改善其抗爆裂性能;在试验参数范围内,每立方米混凝土中掺入1.5kg的PP纤维能够显著提高受火后高强混凝土抗压强度;而在每立方米混凝土中掺入2kg PP纤维能够有效减少受火后混凝土的质量损失。 相似文献
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对粗骨料取代率为100%的再生混凝土进行配合比试验研究,探讨单位体积用水量、水灰比、砂率、粉煤灰掺量等对再生骨料混凝土强度的影响。 相似文献
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为了提高水泥胶砂的力学性能,提出在水泥胶砂中掺加外加剂的方法,通过在水泥胶砂中单掺引气剂、复掺引气剂与减水剂两种途径,进行水泥胶砂抗折强度检测试验,对比确定水泥胶砂力学性能最优的引气剂型号及其最佳掺量.结果表明:引气剂与减水剂复掺时水泥胶砂的抗折强度明显大于引气剂单掺时水泥胶砂的抗折强度,2#引气剂最能满足水泥胶砂抗折强度要求. 相似文献
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吴瑾 《连云港职业大学学报》1999,12(4):43-50
本试验研究利用新海电厂原状干排粉煤灰及其它常规原材料,研制出坍落度达190－260mm,28天抗压强度达50－75MPa,抗渗等级超过S20的主强粉煤灰砼,本试验研究讨论了粉煤灰掺量,胶材总量、砂率,水胶比,减水剂品种与掺量等参数对砼强度和流动性的影响,还讨论了粉煤灰掺量对砼抗渗性能的影响。 相似文献
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通过不同纤维掺量、不同养护龄期下钢纤维混凝土的力学性能试验,研究钢纤维掺量对混凝土抗压强度和抗折强度的影响。结果表明,钢纤维对混凝土抗压强度和抗折强度均有明显增强作用,掺量为1．6％时强度最大。 相似文献
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试验研究了砂率、石子级配以及搅拌与成型工艺对透水混凝土主要性能的影响。试验结果表明：砂率和石子级配对混凝土的抗压强度有利,但同时对透水系数有着负面的影响;机械成型对混凝土强度有益而对透水系数有影响,但影响不显著。合理解决这些问题能为配置高性能透水混凝土提供依据。 相似文献
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由于再生骨料混凝土的强度和耐久性低于普通骨料混凝土,再生骨料的使用一直没有被广泛普及。为了提高再生粗骨料混凝土的物理性能,本文提出了利用高炉矿渣砂制造再生粗骨料混凝土。高炉矿渣砂的使用将能够有效地改善混凝土的耐久性和抗冻融损伤性能。在普通混凝土长期性能和耐久性能试验方法标准中的抗冻试验方法的基础上,使用液氮进行快速冻融试验,对经处理的低等级再生粗骨料和高炉矿渣砂混凝土的泌水性能、抗压强度和抗冻融性能进行了研究,结果表明,采用经处理的低等级再生粗骨料和用高炉矿渣砂替代50%或30%的破碎砂的混凝土有优良的泌水和抗冻融性能。 相似文献
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通过对中强钢纤维混凝土进行试验，分析了钢纤维体积率与中强混凝土强度增幅之间的关系。试验结果表明，砂率不同，对混凝土的增强效果不同；随着钢纤维体积率的提高，中强混凝土抗压和抗拉强度都有不同程度的提高，抗拉强度则是大幅度提高。 相似文献
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《佳木斯教育学院学报》2016,(11)
ERP沙盘模拟经营课程作为一门实验实训课程,近年来已经成为越来越多高校经管类专业的必修课程,深受高校学生的欢迎。随着课程的开展与深入,也逐渐暴露出课程本身存在的问题,本文就目前ERP沙盘模拟经营课程的改革发展的新动态做了详细的阐述, 相似文献
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民办本科院校的转型与发展 总被引：3，自引：0，他引：3
本文通过回顾民办高等教育发展历程,在总结民办本科院校已有的竞争优势的基础上,提出民办高校要在新一轮竞争中取胜并持续发展,必须重新审视自身的办学定位与发展潜能,实现从战术选择到战略规划、从外在形象设计到组织内涵建设、从同质化到差异化竞争、从人事管理到人本管理的转型,促进大众化高等教育多样化发展. 相似文献
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Huai-feng Peng Gang-qiang Kong Han-long Liu Hossam Abuel-Naga Yao-hu Hao 《浙江大学学报(A卷英文版)》2018,19(8):638-649
This paper presents the experimental results of small-scale model tests of an instrumented floating energy pile group in which the piles were embedded in dry medium-dense sand and subjected to the seasonal temperature pattern of the city of Nanjing in China. The study also included a model test to assess the effect of including nonthermal piles on the thermo-mechanical behaviour of the floating energy pile group. For comparison, a model test of a single floating energy pile embedded in the same soil and subjected to a similar temperature pattern was also conducted. The results show that the thermo-mechanical behaviour of an energy pile group is different from that of a single energy pile in terms of the thermally induced change in axial pile stress and the displacement of the pile top and tip. This difference in behaviour could be explained by the higher lateral confining pressure expected on a single pile than on a pile in a group due to pile interaction effects, which could lead to different end restraint boundary conditions. We conclude that the thermo-mechanical behaviour of an energy pile is controlled mainly by the end restraint boundary conditions. 相似文献
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An inclined seven-story reinforced concrete building was leveled by a fracture grouting technique with quick-setting grout on a differential thickness of a clayey sand layer. The permeability and strength of clayey sand were controlled by clay content, although sand was the primary component of the foundation soil. The elevations of the building columns at basement level were closely monitored to record both the heaved volume of mat foundation after grouting and the settled volume during pore pressure dissipation. During the stabilizing stage of grouting, the foundation soil was densified by the repetitive fracturing process, which resulted in the lateral movement of the foundation soil. When the grout is less able to push soil laterally than upwards, the building starts to lift, the so-called lifting stage of grouting. The grouting efficiency is influenced by soil type, soil stress history, and foundation pressure. A final grouting efficiency of 27% and a linear relationship between grout use and percentage of elevation were obtained when this building was successfully and permanently leveled. 相似文献
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Meen-wah Gui 《浙江大学学报(A卷英文版)》2011,12(1):15-23
The penetration of a model pile through sand was investigated via a numerical analysis. Data from nine triaxial compression tests on dense specimens at different stress levels was generalized and used to create an empirical non-linear plastic hardening stress-strain relation for use in the analysis. As the computer program used is capable of large displacement analyses in radial symmetry, we expected that the analysis would easily reproduce the tip resistance penetration profile of the model pile in sand of known density and stress. However, initial attempts led to over-prediction. Successful analyses required both successive reformations of the mesh and the complete elimination of the dilatant peak in soil strength, which is naturally eliminated under large confining stress directly beneath the advancing tip, and that soil in the far-field had strained insufficiently to reach peak strength. Thus, the soil around the shaft must have been sheared to a critical state as it flowed past the tip. The hypothesis that the resistance to displacement piles in sand is mainly a function of the deformability of the sand was again proven, and the use of peak strength in the traditional bearing capacity formulae was found to be inappropriate. Independent investigation in this direction is needed to quantify the hypothesis. 相似文献
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