带裂缝混凝土的吸水性能及防水处理的影响

A series of small size RC beams were introduced with different crack widths and then treated with silane-based water repellent on the surface and inside the concrete. Their water absorption properties were then evaluated. The results indicate that a linear function of square root of time could describe well the water absorption for cracked concrete within 4 h of the test, the coefficient of water absorption increases with the increase of crack width following an ″S″ shape. For the cracked concrete with surface water repellent treatment, water vapor diffuses into concrete along the crack depth and then devaporates behind the hydrophobic layer, and finally a water absorption pathway with the outside is established. The efficiency of water repellent treatment depends on the thickness of hydrophobic layer and the crack width. While the internal water repellent concrete is integrally hydrophobic, the efficiency of treatment is well-maintained even the crack width is increased up to 0.4 mm.