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The effect of the methylene blue (MB) - value of manufactured sand on the durability of concretes



Author(s): Jiliang Wang, Dapeng Wang, Ying Liu, Yudong Yuan
Paper category: Conference
Book title: 2nd International conference on Microstructural-related Durability of Cementitious Composites
Editor(s): Guang Ye, K. Van Breugel, Wei Sun, Changwen Miao
Print ISBN: 978-2-35158-129-2
e-ISBN: 978-2-35158-123-0
Publisher: RILEM Publications SARL
Pages: 1511- 1520
Total Pages: 9
Language: English


Abstract: 
The MB-value is one of the most important parameters for evaluating the properties of manufactured sand (MS). 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, and the mechanical properties, the resistance to freezing as well as the resistance to chlorine ion permeation of the hardened concrete were investigated. 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 the MB value, the concrete workability decreased, as did the flexural and 7-day compressive strengths, however the 28-day compressive strength was not affected. Furthermore, the influence of the MB value on concretes of different strength levels was different. For low-strength concretes, an increase of the 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 the MB value remarkably accelerated freeze-thaw damage of the 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.


Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00