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真空辅助压浆是在孔道的一端采用真空泵对孔道进行真空处理,使孔道内的真空度达到80%以上,产生-0.06至0.1Mpa的真空度,然后用灌浆泵将优化后的水泥浆从孔道的另一端灌入,并加以≥0.7Mpa的正压力。由于孔道内只有极少的空气,很难形成气泡;由于孔道与压浆机之间的正负压力差,大大提高了孔道压浆的饱满度和密实度;由于减小了水灰比,添加了专用的添加剂,提高了水泥浆的流动度,减小了水泥浆的的收缩,从而保证了浆体的可施工性、充盈孔道的密实性和提高硬化浆体的强度。因此真空压浆工艺是提高后张预应力混凝土结构安全度和耐久性的有效措施。
Vacuum-assisted grouting is the use of a vacuum pump at one end of the tunnel vacuum treatment of the tunnel, the vacuum within the tunnel to reach more than 80%, resulting in a vacuum of -0.06 to 0.1Mpa, and then grouting pump will be optimized slurry from the tunnel The other end of the filling, and to be ≥ 0.7Mpa positive pressure. Because there is very little air in the channel, it is difficult to form bubbles. Due to the positive and negative pressure difference between the channel and the press, it greatly improves the plumpness and compactness of the channel grouting. Due to the reduction of the water-cement ratio, The special additives improve the fluidity of the cement slurry and reduce the shrinkage of the cement slurry so as to ensure the workability of the slurry, the compactness of the filled pores and the strength of the hardened slurry. Therefore vacuum grouting process is to improve post-tensioned prestressed concrete structure safety and durability of effective measures.