不同温度下低热混凝土强度及孔结构分形特征研究OA北大核心CSTPCD

[Objective]In order to explore the relationship between microscopic structure evolution law and macroscopic mechani-cal properties of low-heat concrete under real temperature environment,[Methods]the compressive strength and pore structure tests of low-heat concrete under different temperatures(20 ℃,30 ℃,40 ℃)were designed and carried out.Based on the scanning electron microscope(SEM)images,the fractal dimension of low-heat concrete was calculated by the box dimension method.Finally,a compressive strength prediction model considering fractal dimension was established.[Results]The results show that under high temperature curing,the most probable pore diameter and porosity decrease,the fractal dimension increases from 1.796 8 to 1.886 8,and the compressive strength increases significantly.[Conclusion]The microscopic space state corre-sponding to 36％～42％porosity and 10～20 nm pore diameter is most complex,high temperature curing increases the pore size content of 10～20 nm and effectively improves the compressive strength.The prediction model can quantitatively describe the cou-pling relationship between mechanical properties of low-heat concrete and fractal dimension of pore structure,which provide theo-retical support for the durability and safety design of dam concrete under different temperatures.