What are the factors affecting the setting time of

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Workability refers to the performance that the concrete grouting mixture is easy to operate and can obtain uniform quality. It is a comprehensive technical index, including fluidity, cohesion and water retention. The rheology of concrete grouting material is related to the rheological parameters of cement paste. At the same time, the pouring conditions also have an impact on the workability of concrete grouting materials. The concrete grouting material with good workability should be neither bleeding nor segregation. The greater the unit water consumption of concrete grouting material, the greater its slump

mixing water reducing agent and air entraining agent can greatly improve the workability of concrete grouting materials, and can realize large fluidity concrete grouting materials, pumping concrete grouting materials and self compacting concrete grouting materials. Generally speaking, the factors that affect the workability of concrete grouting materials include the plasticity of cement slurry, coarse aggregate, maximum particle size and gradation, aggregate morphology and surface characteristics. Sometimes, the concrete grouting material mixing plant or the construction unit uses coarse aggregate with high water absorption, which leads to the slump loss of concrete grouting material over time. When the situation is unknown, it is often considered that the chemical admixture of concrete grouting material used is not suitable for cement. In fact, if the water absorbed by the coarse aggregate is supplemented within 1~2h, the workability of the concrete grouting material will remain normal

the setting of concrete grouting material is related to the properties of mortar contained in concrete grouting material. Grouting agent usually uses penetration resistance method to measure the initial and final setting time of cement mortar in concrete grouting material to characterize the setting time of concrete grouting material

when the concrete grouting material has flash setting, the original workability will disappear after re mixing. False setting will also occur when chemical admixtures are not suitable for the varieties of cement or admixture. Adding molasses water reducer, lignin sulfate, citric acid, phosphate, sucrose and other substances can delay the hydration of cement, thus delaying the setting time of concrete grouting materials. When sodium sulfate, triethanolamine and other substances are mixed, the setting time of concrete grouting material will be shortened. The setting time of concrete grouting material is delayed compared with that of cement

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