荷载作用下粉煤灰混凝土一维、二维碳化研究

对不同粉煤灰掺量(0%,20%,40%,60%)、不同应力比(0.20,0.35,0.50,0.65,0.80)下高性能混凝土一维和二维碳化规律展开研究;建立了荷载作用下二维碳化测试方法;定义了二维碳化交互系数;研究了不同应力比对交互系数的影响规律。试验表明:一维、二维碳化深度随着应力比的提高而增加,碳化28 d时(相当于自然碳化50 a),应力比为0.8时的一维、二维碳化深度分别是应力比为0时的1.61倍、1.39倍;同时,碳化深度服从应力比的指数函数关系;混凝土二维碳化具有显著的交互作用,荷载作用下的二维交互系数明显小于不受力时的交互系数,并且随着应力比的增加,其数值有变小的趋势。混凝土加载状态下的一维和二维碳化研究对混凝土结构耐久性和寿命预测具有现实意义。

RESEARCH ON 1 DIMENSION AND 2 DIMENSION CARBONATION OF FLY ASH CONCRETE UNDER LOADING

The 1D and 2D carbonations of high performance concrete are studied under different fly ash proportion(0%,20%,40%,60%) and different ratio of bending load(0.20,0.35,0.50,0.65,0.80).The test method of 2D carbonation under loading is built;The interaction coefficient of 2D carbonation is defined.The influence of different bending load ratio on interaction coefficient is studied.The experiment indicates that carbonation depth of 1D and 2D are increased with the raising ratio of bending load.During the carbonation of 28 d(corresponding to nature carbonation of 50 years),the 1D and 2D carbonation depth under 0.8 ratio of bending load are 1.61 times and 1.39 times as compared to 0 ratio of bending load.At the same time,the depths of carbonation subject to the exponential function of bending load ratio.The 2D carbonation of concrete has an obvious interaction coefficient.The 2D interaction coefficient with load is much smaller than the interaction coefficient without load.And with the increase of stress ratio,the value of interaction coefficient trends to decrease.The research on the 1D and 2D carbonations of concrete under bending load possesses the real meaning to the structure durability and life prediction of concrete.