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本文阐述了高性能免振自密实混凝土的原理及获得免振自密实混凝土的技术路线,确定了高性能免振自密实混凝土工作性的评价指标。 相似文献
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高性能混凝土技术发展的一些动态和问题 总被引:3,自引:0,他引:3
首先指出了高性能混凝土与高强混凝土的区别,提出了高性能混凝土当前在性能上尚存在的两个问题:(1)自干燥引起的自收缩;(2)脆性及改善上述性能问题的技术措施,并介绍了高性能混凝土技术发展中的一个分--免振自密实混凝土的机制与机理。 相似文献
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C100自密实钢管混凝土在深圳南方国际广场的应用 总被引:2,自引:0,他引:2
本文通过对材料优选、严格的试配、现场模拟试验,研制出C100高性能免振自密实钢管混凝土,混凝土具有良好的施工性能和耐久性能。 相似文献
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首先指出了高性能混凝土与高强混凝土的区别.提出了高性能混凝土当前在性能上尚存在的两个问题(1)自干燥引起的自收缩;(2)脆性及改善上述性能问题的技术措施.并介绍了高性能混凝土技术发展中的一个分支--免振自密实混凝土的机制与机理. 相似文献
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免振高性能混凝土拌合物工作性检测方法及评价指标的研究 总被引:13,自引:1,他引:12
本文对兔振高性能混凝土拌合物采用了坍落度法,坍落度扩度、L型流动度法、Orimet法对新拌混凝土流动性、粘性、填充性、抗离极性进行了对比研究,以免振成型立方体型表观密度经及抗压强度比为参照,初步提出了免振高性能混凝土拌合物工作性检测方法及评价指标。 相似文献
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普通纤维混凝土因可泵送性差很少用于索塔锚固区。采用多重复合技术,优选纤维混凝土配合比,并研究了各配合比的泵送性能;模拟干热环境,对优选的高性能混凝土(HPC)和钢锚箱锚固区专用高性能钢纤维混凝土(HPSFRC)进行了塑性收缩试验;研究了纤维掺量和减缩剂对塑性收缩和干燥收缩性能的影响,并对其机理进行了探讨。研究表明,经优化的高性能钢纤维混凝土2h内泵送性能优良。随着纤维掺量的增加,塑性收缩的开裂总面积下降,混凝土的抗裂等级提高。当钢纤维的体积掺量为0.8%时,高性能钢纤维混凝土自由干燥90d的收缩值同高性能混凝土相比下降了50%;有约束的干燥收缩66d试验环未见开裂,从而减少混凝土开裂的风湿,提高混凝土结构的耐久性。与同强度等级的高性能混凝土相比,钢纤维的加入也改善了混凝土的力学性能,高性能钢纤维混凝土的抗弯强度和劈拉强度提高了近30%。试验结果还表明,纤维体积率为0.6%的钢纤维与减缩剂复合后,对抑制塑性收缩和干燥收缩效果显著。 相似文献
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高性能混凝土的自收缩性能研究 总被引:8,自引:0,他引:8
实验研究了混凝土干缩及自收缩性能,结果表明,高性能混凝土具有严重的自收缩现象,但整体的干缩与普通混凝土相似,掺入硅灰将将大高性能混凝土的自收缩。 相似文献
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用不同粗骨料(石灰石碎石、再生粗骨料)、细骨料(河砂、人工砂、再生细骨料)两两相组合,共配制6组高性能混凝土进行对比试验,测试抗压强度、弹性模量、收缩和徐变4个性能指标并进行显著性分析。结果表明,骨料类型对高性能混凝土抗压强度的影响不明显,但对弹性模量、收缩和徐变性能都有显著影响。粗骨料对弹性模量和收缩性能的影响较为显著,细骨料对徐变的影响较为显著。再生粗骨料混凝土收缩、徐变早期发展较慢,而中后期的发展速度明显快于普通混凝土;再生细骨料混凝土收缩、徐变的发展速度始终远快于普通混凝土。在此基础上,提出了考虑粗、细骨料类型和骨料种类的高性能混凝土收缩和徐变的预测模型。 相似文献
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The investigation on the workability of fibre cocktail reinforced self-compacting high performance concrete 总被引:2,自引:0,他引:2
The workability, the strength and the toughness are the significant factors for self-compacting-high performance concrete (SCHPC). The workability is a significant precondition for application of the Fibre Reinforced SCHPC. This paper presents research results on the workability of Monofibre and Fibre Cocktail (hybrid steel-polypropylene fibre) Reinforced SCHPC. Lots of mixtures made with steel fibres, PP-fibres and fibre cocktail of various dosages have been investigated. The mixtures were tested using various new methods for evaluating the flowability, filling ability and segregation risk of the fresh mortar/concrete. Based on the results of the workability, the suitable fibre types (steel fibres, PP-fibres and fibre cocktail) and the upper level of the fibre dosages for Fibre Reinforced SCHPC have been selected for study of the mechanical behaviour and the failure patterns in the next phase. 相似文献
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Bart Craeye Matthew Geirnaert Geert De Schutter 《Construction and Building Materials》2011,25(1):1-13
High-performance concrete (HPC) with low w/b-ratio experiences a considerable chemical shrinkage and self-desiccation during its hydration process, leading to a rather high autogenous shrinkage deformation during hardening. In case the free deformation of the concrete is prevented, internal stresses are introduced, which can lead to premature cracks. These early-age cracks can severely affect the durability of a concrete structure. By adding super absorbing polymers (SAP) into the HPC as an internal curing agent, and by adding additional curing water to the concrete mixture, the chemical shrinkage and the self-desiccation during hydration of the concrete is counteracted and thus the autogenous shrinkage of the HPC can be significantly reduced. Unfortunately, this process of internal curing also has some disadvantageous effects on the mechanical properties. In search of an optimization of the internal curing process, an extensive experimental program was performed on HPC, using different degrees of internal curing, to assess the mechanical and thermal properties of the HPC, and to evaluate the effectiveness of the performed curing. The goal is to obtain a maximal autogenous shrinkage reduction and a minimal strength reduction. The resulting effect on the early-age cracking risk is simulated by means of finite element calculations. The simulations also include thermal stress development due to the heat of hydration. In case 70 kg/m3 of internal curing water is provided via the SAP, an optimal reduction of the cracking risk is noticed, mainly caused by the autogenous shrinkage reduction and the appearing expansive deformation peak directly after setting takes place. 相似文献
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为研究矿物掺合料对高性能混凝土自收缩的影响及其计算模型,采用混凝土自收缩无接触自动测试装置进行粉煤灰掺量及品质、粉煤灰与偏高岭土复掺及粉煤灰与矿渣复掺对高性能混凝土自收缩性能的影响。研究结果表明:随着粉煤灰掺量的增加,高性能混凝土的自收缩值随之下降;在同掺量下,提高粉煤灰的品质可降低高性能混凝土的自收缩值。在粉煤灰高性能混凝土中复掺偏高岭土会增大其自收缩值;粉煤灰与矿渣复掺可进一步降低高性能混凝土的自收缩值,且在复掺比例为1∶1时最佳。通过对现有混凝土自收缩计算模型与试验数据对比分析,提出高性能混凝土自收缩计算模型,该模型计算结果与试验结果吻合良好。 相似文献