The relation between the methylene blue （MB） value of MS and its limestone powder content and clay content was investigated. The effects of MB values ranging from 0.35 to 2.5 on the workability of fresh concrete, th...The relation between the methylene blue （MB） value of MS and its limestone powder content and clay content was investigated. The effects of MB values ranging from 0.35 to 2.5 on the workability of fresh concrete, the mechanical properties, the resistance to freezing as well as the resistance to chlorine ion permeation of the hardened concrete were all investigated. The experimental results showed that the MB value had no correlation with the limestone powder content of MS, while it was directly related to the clay content. With an increase of MB value, concrete workability decreased, as did the flexural and 7-day compressive strengths, however, the 28-day compressive strength was not affected. Furthermore, influence of MB value on concretes of different strength levels was different. For low-strength concretes, an increase of MB value could improve its impermeability, but this was not the case for high-strength concretes. Instead, their resistance to chloride ion permeability decreased slightly. However, even a slight increase in MB value remarkably accelerated freeze-thaw damage of MS concrete. It was thus concluded that the critical MB value of 1.4 would not cause significant deterioration in the performance of MS concretes.展开更多
The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack ...The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack propagation characteristics at the age of 24 hours, and effects on the mechanical properties, dry shrinkage of the harden concrete were tested. The experimental results show that the MB value is not related with the limestone dust content of MS, but in direct proportion to clay content. With the increase of MB value, the concrete workability decreases, and the flexural strength and 7 d compressive strength reduce markedly, whearas the 28 d compressive strength is not affected. When the MB-value is less than or equal to 1.35, the change of the MB-value has a little influence on early plastic cracking and dry shrinkage property of concrete, but when the MB-value is more than 1.35, the tendency of plastic cracking and dry shrinkage is remarkable.展开更多
人工砂中的泥粉对混凝土的力学、干燥收缩和耐久性能会产生不利影响。为了给人工砂生产和使用提供合理建议,梳理了已有文献中使用固定配合比配制不同含泥量或亚甲基蓝值(Methylene Blue Value,简称MB值)的人工砂混凝土,从混凝土强度、...人工砂中的泥粉对混凝土的力学、干燥收缩和耐久性能会产生不利影响。为了给人工砂生产和使用提供合理建议,梳理了已有文献中使用固定配合比配制不同含泥量或亚甲基蓝值(Methylene Blue Value,简称MB值)的人工砂混凝土,从混凝土强度、弹性模量、干燥收缩性能、耐久性4方面分析总结了混凝土性能受人工砂泥粉的影响规律。研究结果表明:随着人工砂MB值的增加,混凝土各项性能皆有劣化的趋势,且强度等级越高的混凝土受到的影响越大;人工砂MB值对混凝土抗压强度、干燥收缩性能、弹性模量有显著影响的临界值分别为1.2,1.45,2.1左右。展开更多
基金Funded by the National West Communication Construction Technology Project(No.200731822301-6)
文摘The relation between the methylene blue （MB） value of MS and its limestone powder content and clay content was investigated. The effects of MB values ranging from 0.35 to 2.5 on the workability of fresh concrete, the mechanical properties, the resistance to freezing as well as the resistance to chlorine ion permeation of the hardened concrete were all investigated. The experimental results showed that the MB value had no correlation with the limestone powder content of MS, while it was directly related to the clay content. With an increase of MB value, concrete workability decreased, as did the flexural and 7-day compressive strengths, however, the 28-day compressive strength was not affected. Furthermore, influence of MB value on concretes of different strength levels was different. For low-strength concretes, an increase of MB value could improve its impermeability, but this was not the case for high-strength concretes. Instead, their resistance to chloride ion permeability decreased slightly. However, even a slight increase in MB value remarkably accelerated freeze-thaw damage of MS concrete. It was thus concluded that the critical MB value of 1.4 would not cause significant deterioration in the performance of MS concretes.
基金Funded by the Nationd West Communication Construction Technology Project(No.200331881106)
文摘The relation between methylene blue （MB） value of MS and its limestone dust content and clay content was investigated. The effects of MB value ranging from 0.35 to 2.5 on the workability of fresh concrete and crack propagation characteristics at the age of 24 hours, and effects on the mechanical properties, dry shrinkage of the harden concrete were tested. The experimental results show that the MB value is not related with the limestone dust content of MS, but in direct proportion to clay content. With the increase of MB value, the concrete workability decreases, and the flexural strength and 7 d compressive strength reduce markedly, whearas the 28 d compressive strength is not affected. When the MB-value is less than or equal to 1.35, the change of the MB-value has a little influence on early plastic cracking and dry shrinkage property of concrete, but when the MB-value is more than 1.35, the tendency of plastic cracking and dry shrinkage is remarkable.
文摘人工砂中的泥粉对混凝土的力学、干燥收缩和耐久性能会产生不利影响。为了给人工砂生产和使用提供合理建议,梳理了已有文献中使用固定配合比配制不同含泥量或亚甲基蓝值(Methylene Blue Value,简称MB值)的人工砂混凝土,从混凝土强度、弹性模量、干燥收缩性能、耐久性4方面分析总结了混凝土性能受人工砂泥粉的影响规律。研究结果表明:随着人工砂MB值的增加,混凝土各项性能皆有劣化的趋势,且强度等级越高的混凝土受到的影响越大;人工砂MB值对混凝土抗压强度、干燥收缩性能、弹性模量有显著影响的临界值分别为1.2,1.45,2.1左右。
