Cause analysis and preventive measures on the workability of super high-rise concrete

1 Reason Analysis

The working performance of concrete is stable. The concrete construction period of super high-rise buildings is longer than that of ordinary projects. Concrete needs Keep cycle performance stable. However, the pumping performance of concrete has different requirements with pumping height, seasonal changes, etc. When the concrete slump is too small, the concrete lubricating layer is thinner and the friction resistance increases. When the concrete slump is large and segregates, the concrete will segregate over long distances. Concrete stones in pipes are easy to sink, causing accumulation and blockage; such as segregation and bleeding, the concrete mortar is easy to dig out the bottom, causing pipe blockage.

2 Preventive Measures

Develop strict workability control standards for concrete pumps and resolutely implement them. Under the same construction conditions (double-click high pressure, displacement of 50%), when the C60 concrete pumping height is 300m, the influence of different expansion degrees on the pump pressure is shown in Table 1, which indicates that the concrete is within the pumpability range. , the pumping pressure is inversely proportional to the fluidity, that is, during construction, appropriately increasing the fluidity of concrete will help improve construction efficiency. </p