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随着混凝土技术的发展,混凝土耐久性变得越来越重要,高性能混凝土得到了广泛应用.本文主要探讨了高性能混凝土的涵义及其特点,分析了高性能混凝土的组成材料与选择及高性能混凝土施工及养护过程的问题. 相似文献
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丁以兵 《四川建筑科学研究》2011,37(2):197-200
养护的有效性与否,严重影响到高性能混凝土的性能,养护的温度和湿度,是影响其性能的关键因素。文中分析了高性能混凝土的结构特点并阐明了其养护的独特机理,列举了几种传统的养护方法。但由于高性能混凝土的特点,传统措施不适用高性能混凝土。而自养护混凝土在控制各种收缩变形、提高水泥水化、改善微观结构以及增强耐久性能等方面,效果显著,表明自养护技术可以成功地应用于外部养护相对不敏感的高性能混凝土之中。 相似文献
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论述了粉煤灰高性能混凝土的试验及养护方法,就养护条件对粉煤灰高性能混凝土强度和变形性的影响进行了分析,总结了相关经验,为提高混凝土的耐久性和强度提供了参考。 相似文献
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介绍了高性能混凝土施工前的准备工作,从原材料、混凝土的搅拌、浇筑、振捣、养护及拆模等方面就高性能混凝土施工质量的监理控制进行了探讨,提出了不同环境气温下混凝土的质量控制措施,以确保高性能混凝土的质量. 相似文献
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随着混凝土技术的发展,混凝土耐久性变得越来越重要,高性能混凝土得到了广泛应用。本文主要探讨了高性能混凝土的涵义及其特点,分析了高性能混凝土的组成材料与选择及高性能混凝土施工及养护过程的问题。 相似文献
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C60高性能蒸汽养护混凝土试验研究 总被引:1,自引:0,他引:1
通过试验研究,配制出满足设计要求的C60高性能蒸汽养护混凝土,与标准养护混凝土相比,其强度及耐久性能均有一定程度的损失,但采用正交试验、高性能混凝土技术、弱蒸汽养护制度能降低蒸汽养护带来的不利影响,配制出满足工程使用的高性能蒸汽养护混凝土。 相似文献
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《Construction and Building Materials》2010,24(1):94-98
The use of ultrasonic relative amplitude ratio (RAR) and ultrasonic pulse velocity (UPV) to evaluate the strength of high performance concrete (HPC) with 10%, 20% and 30% silica fume content at water/binder ratios from 0.22 to 0.40 with different curing conditions is presented in this paper. As the composition, maturity, free water content and curing conditions are factors that influence the strength of concrete, their effect on the measured UPV and the RAR are determined. Results show that UPV measurement is less sensitive at high level of strength but has good correlation with the compressive strength of HPC with silica fume, whereas RAR maintain good sensitivity at all level of strength (irrespective of the factors that influence the strength) with reduced correlation coefficient. The suggested combined UPV and RAR-strength correlation can be used to estimate the compressive strength of HPC with silica fume and can be combined with other nondestructive testing methods for better estimation of strength. 相似文献
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Experimental study of early-age behavior of high performance concrete deck slabs under different curing methods 总被引:3,自引:0,他引:3
Curing techniques and curing duration have crucial effects to the strength and durability of concrete. Proper curing can protect against moisture loss from fresh concrete. The objective of this experimental study is to examine the early-age behavior of high-performance concrete (HPC) under various curing methods. Laboratory experiments were conducted to investigate the early-age shrinkage development, temperature change, and evaporation rate when different curing methods were used. Four curing techniques and two curing durations were applied to concrete deck slab and cylindrical specimens. The measured experiment data were also compared with several shrinkage prediction models. The results show that proper moisture-curing methods can effectively reduce concrete temperature due to hydration heat and limit the development of early-age shrinkage strains. The concrete of a longer curing duration would yield lower shrinkage deformation and lower evaporation rate. 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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高性能混凝土产业化发展的若干思考 总被引:2,自引:0,他引:2
本文通过对高强高性能混凝土的研究应用回顾,提出了普通混凝土高性能化是今后我国高性能混凝土产业化发展的主导方向,也是解决当前泵送混凝土普遍存在的早期开裂趋势明显的主要技术途径。对制约高性能混凝土产业化发展的水泥品质、现行规范和施工养护工艺等因素作了深入阐述。 相似文献
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约束条件下高性能混凝土的早期开裂 总被引:28,自引:3,他引:28
早期收缩开裂是高性能混凝土,特别是大流动度混凝土施工应用中经常出现的质量通病。这种裂缝的产生主要与混凝土配合比、养护条件及混凝土所处约束条件有关。本文对掺硅灰、粉煤灰等矿物掺合料的高性能混凝土在约束条件下的早期开裂进行试验研究。结果表明:掺硅灰加剧了混凝土的早期开裂;优质磨细粉煤灰的加入对混凝土早期开裂有一定的抑制作用。 相似文献
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高性能混凝土中饱水轻集料的微养护作用及其机理 总被引:6,自引:0,他引:6
在高性能混凝土中掺用适量的饱水轻集料,可提高其内部相对湿度,促使水泥达到最大水化程度,并减少混凝土结构的开裂机率。本文阐述了微养护的重要性,分析了微养护的作用机理,提出了微养护所需轻集料用量的计算方法。 相似文献
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本文介绍了京沪高速铁路中采用大掺量矿物掺合料进行高性能混凝土的配制和施工技术,从混凝土的配合比设计、浇筑与养护等主要环节进行施工控制,指出了大掺量高性能混凝土的施工注意事项。 相似文献
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介绍了国内外HPC配合比设计的方法,各种方法所存在的共同缺陷就是不能反应HPC配合比设计受多种因素的综合影响,对此我们应用BP人工神经网络来进行HPC配合比设计,结果表明,该方法很好地为HPC配合比设计提出了一条可行之路。 相似文献