高温作用下活性粉末混凝土(RPC)孔隙结构的分形特征

为能定量表征温度作用下RPC内部孔隙结构的变化特征，采用压汞测孔法对高温后活性粉末混凝土(RPC)内部的孔隙结构和孔隙的分形特征进行了实验研究。分析了孔隙体积、阈值孔径、最可几孔径等孔隙特征参数随温度变化的规律；计算分析了毛细孔和过渡孔等有效孔径区间内RPC的体积分形维数及其随温度的变化规律。研究表明：温度影响下，RPC内部孔隙结构表现出劣化特征，孔隙率、孔隙体积等特征参数明显增大；RPC内部的损伤过程可以采用分形方法去描述，150 ℃时，RPC初步呈现分形效应，在毛细孔和过渡孔的孔径范围内RPC的体积分形维数整体表现出增大趋势。

Investigation on fractal characteristic of Reactive Powder Concrete pore structure subject to high temperature

To quantitalively prove the effect of temperature on RPC internal pore structure changes，the characteristics of pore structure and the fractality of RPC after high temperatures were tested by mercury intrusion porosimetry(MIP).The development of the characteristics of pore parameters，such as the pore volume，the threshold pore size，the most probable pore size，etc.，with increasing temperature was analyzed.The volume fractal dimension of RPC in the effective region of capillary pores and transition pores were calculated.The results indicate that the pore structure degrades at high temperature，which lead to the porosity and pore volume increase with the temperature rising.The damage process of RPC can be described by means of the fractal method，at the temperature 150 ℃，RPC starts to show fractal effect，the volume fractal dimension of RPC in the range of capillary pores and transition pores increase with the rising temperature.