孔隙水对湿态混凝土抗压强度的影响

EFFECT OF PORE WATER ON THE COMPRESSIVE STRENGTH OF WET CONCRETE

湿态混凝土受压时会产生孔隙水压力,孔隙水压力的大小与混凝土的变形和裂纹的扩展速度相关。孔隙水压力的产生给混凝土的力学性能带来一些影响,但是目前这方面的理论研究甚微。尝试利用断裂力学的方法,来探讨湿态混凝土在承受单轴压缩荷载时,孔隙水压力对混凝土开裂、扩展和抗压强度的影响。研究结果表明:混凝土中的孔隙水压力减小了阻碍混凝土开裂的摩阻力,相当于楔体的“楔入”作用,加速了混凝土的损伤和微裂纹的扩展,与干燥态的混凝土相比,湿态混凝土的开裂应力和抗压强度都有所降低。

The compressive strength of wet concrete influenced by pore water is investigated in this paper. Pore water pressure induced by compression in the wet concrete affects the mechanical properties of concrete, but the related research is little. The magnitude of pore pressure relates with the volumetric deformation of concrete and the developing velocity of cracks. Based on fracture mechanics, the effects of pore water on the initiation of crack, the development of crack and the strength of wet concrete are analyzed. The results of this investigation indicate that the pore water decreases the friction force which baffles the development of crack and accelerates the damage of concrete, and the pore pressure acts as a wedge to the crack of concrete. The initiation stress of crack and the compressive strength of wet concrete are decreased comparing with the dry sample.