Effect of entrained air voids on the microstructure and mass transport properties of concrete
Effect of entrained air voids on the microstructure and mass transport properties of concrete
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DOI：
10.1016/j.cemconres.2011.06.013
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发表时间：
2011-10
影响因子：
11.4
通讯作者：
H. Wong;A. Pappas;R. Zimmerman;N. Buenfeld
中科院分区：
文献类型：
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作者：
H. Wong;A. Pappas;R. Zimmerman;N. Buenfeld
研究了不同水灰比、养护和调质条件下引气对含气量达11.5%的混凝土微观结构和传输性能的影响。结果发现，空气空隙破坏水泥的包装，并增加微观结构的不均匀性。受影响界面的宽度约为30μm。在最高空气含量下，气体扩散率和渗透率增加到2-3倍。这种效果类似于当样品在52% r.h或50°C条件下处理时由于w/c比从0.35增加到0.50而引起的效果。对吸附性的影响不太一致，而对电导率的影响受空气空隙的水分条件的影响。据估计，空气含量每增加1%，传输增加10%或减少4%，这取决于空气空隙是作为导体还是绝缘体。
The effects of entrained air on microstructure and transport properties of concrete with up to 11.5% air at different w/c ratios, curing and conditioning regimes were investigated. It was found that air voids disrupt the packing of cement and increase the heterogeneity of the microstructure. The width of the affected interface is around 30μm. Gaseous diffusivity and permeability are increased by up to a factor of 2–3 at the highest air contents. This effect is similar to that due to increasing w/c ratio from 0.35 to 0.50 when samples are conditioned at 52% r.h or 50°C. The effect on sorptivity is less consistent, while the effect on electrical conductivity is influenced by the moisture condition of the air voids. It is estimated that every 1% increase in air content increases transport by 10% or decreases it by 4%, depending on whether the air voids act as conductors or insulators.