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矿物掺合料对碱矿渣混凝土氯离子渗透性的影响 总被引:1,自引:0,他引:1
氯离子渗透是造成混凝土中钢筋锈蚀的主要原因之一。本文采用ASTM C1202规定的氯离子渗透试验方法,研究了粉煤灰和硅灰等量取代矿渣对碱矿渣混凝土氯离子渗透性能的影响。研究表明,在其它条件相同时,碱矿渣混凝土氯离子渗透性随粉煤灰掺量增加而提高,随硅灰掺量增加而降低。从控制碱矿渣混凝土抗氯离子渗透性的角度出发,粉煤灰替代矿渣量宜控制在50%以内。 相似文献
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采用ASTM C1202法及NEL法,对单掺矿渣和复掺粉煤灰、矿渣的高性能混凝土进行抗氯离子渗透性能的试验研究,并探讨电通量与氯离子扩散系数之间的相关性。结果表明:矿物掺合料能有效地改善高性能混凝土的抗氯离子渗透性能,复掺粉煤灰和矿渣比单掺矿渣的效果更佳;电通量与氯离子扩散系数之间具有较好的相关性,当水胶比较小时,两指... 相似文献
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采用ASTMC1202试验方法研究了矿物掺合料对蒸养混凝土抗氯离子渗透性能的影响,试验结果表明:单掺粉煤灰可明显降低180d时混凝土6h库仑电量,以10%粉煤灰与20%矿渣组合等量取代水泥时,28d和180d抗氯离子渗透性最佳。 相似文献
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不同干燥条件对混凝土导电量的影响 总被引:1,自引:0,他引:1
采用ASTM C 1202《混凝土抵抗氯离子渗透能力的电量评价方法》,研究了不同干燥条件对混凝土导电量的影响;在电量试验结束后,检测了氯离子的迁移量和氯离子渗透深度.结果表明:60℃,7 d的干燥条件对水胶比小于0.42且不掺矿物掺和料的基准混凝土及水胶比小于0.49但掺加矿物掺和料的混凝土导电量影响很小,该条件可以作为气体渗透试验的干燥条件;105℃的干燥处理需要慎重,因为该条件会导致混凝土导电量及氯离子迁移量明显增加,混凝土抗渗性能变差;对于电量试验后氯离子渗透深度贯穿的试样,导电量评价标准已不适于评价此类试样的渗透性能,可以考虑将氯离子迁移量或试样的饱水量作为评价其渗透性能的一个定量指标. 相似文献
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《Construction and Building Materials》2007,21(2):356-361
In this paper, the resistance to chloride penetration of concrete containing fly ash of various finenesses was examined. Three different fly ash finenesses viz., original fly ash, 45% fine portion and 10% fine portion fly ashes were used for the study. Chloride resistance of concretes was evaluated using the measurement of the Coulomb charge as per ASTM C1202 and by determination of chloride ingress after different periods of exposure to 3% NaCl solution in full immersion and partial immersion modes. From the tests, it is found that the resistance to chloride penetration of concrete depends on the fineness of fly ash. The rapid chloride permeability test (ASTM C1202) clearly indicates that the Coulomb charge of concrete at the age of 28 days is significantly reduced with the incorporation of fly ash. The decrease is promoted with an increase in fly ash fineness. The immersion of cut cylinders in the 3% NaCl solution for 3 and 6 months confirm that the resistance of the chloride penetration of concrete increases with an incorporation with fly ash and with an increase in the fly ash fineness. 相似文献
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橡胶集料混凝土氯离子渗透性试验研究 总被引:11,自引:0,他引:11
将废旧汽车轮胎经过处理后得到的橡胶细颗粒取代部分骨料配制成橡胶集料混凝土。采用ASTMC1202-97法对5组不同橡胶掺量的混凝土进行抗氯离子渗透性研究,结果表明。橡胶集料混凝土具有很低的氨离子渗透性。28d电量值均小于1000C,且导电量随橡胶掺量增加而减少。 相似文献
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为配合中国建筑学会《混凝土抗氯离子渗透性的交流电测量方法》评价标准的建立,采用了交流电测法、电通量法(ASTM C1202)和快速氯离子扩散系数法(RCM)三种试验方法,定量评价了普通、高强和高性能混凝土抗Cl-渗透的能力。结果表明,当水灰比、粉煤灰及矿渣粉掺量变化时,交流电测法在多数情况下具有较好的适应性;交流电测法与ASTM C1202法、RCM法具有良好的相关性,相关系数分别为0.940 86、0.770 89。 相似文献
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影响混凝土Cl-导电量诸因素的分析 总被引:3,自引:0,他引:3
本文利用ASTM Cl202标准,测量了不同水灰比下掺与不掺矿物质混合材的混凝土6小时总导电量,并对影响混凝土导电量的因素进行了具体分析。试验表明:随水灰比的增加,混凝土导电量明显增加;掺加不同种类的矿物质混合材会降低混凝土导电量,其中硅灰(SF)效果优于粉煤灰(FA),粉煤灰的效果又优于沸石(NZ),而矿渣掺量小于30%时导电量不会降低。存在离析和泌水时,表层混凝土导电量明显高于底层,且各向导性使得混凝土在垂直方向上的导电量各不相同;同时,烘干状态混凝土的电导也各不相同,我们称之为干态电导。这说明对掺加矿物质超细粉后混凝土抗Cl^-渗透性的评价不应仅以导电量为标准,应结合混合材的种类和掺量、混凝主干态电导及由于离析和泌水造成的各向异性等情况进行具体分析。 相似文献
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In chloride containing environment, chloride permeability of concrete is an important parameter affecting the service life of concrete structures. The primary objective of this experimental study was to study the effect of cement types on the resistance of concrete against chloride penetration for given compressive strength classes. These cements included two different types of granulated blast-furnace slag cement (CEM III/A 32.5N and CEM III/A 42.5N), a sulfate resisting cement (SRC 32.5), and a Portland cement blended with fly ash; all of which compared to an ordinary Portland cement (CEM I 42.5R). For each binder type, four concretes at different strength classes were produced and as a result 20 mixtures were obtained. Rapid chloride ion penetration tests according to ASTM C 1202 were conducted. In addition, electrical resistivity and capillary water absorption tests were carried out. In order to characterize the concrete quality, compressive strength of the specimens were also obtained. The test results clearly demonstrated that the blast-furnace slag cements have the highest resistance against chloride penetration, while the pure Portland cement and sulfate resisting cement have the lowest resistance. Concretes produced with the sulfate resisting cement had substantially higher capillary sorption compared to other mixtures. Test results confirmed the strong relationship between the chloride permeability and electrical resistivity. 相似文献