CGM grout material plastic shrinkage crack of preventive measures

How to prevent grouting material plastic shrinkage crack grouting material plastic shrinkage crack grouting material plastic shrinkage crack is refers to the grouting material during condensation sclerosis, caused by surface evaporation drying shrinkage crack; When grouting inside surface moisture evaporating speed higher than that of grouting material from inside to outside 'bleeding' speed, the surface will generate shrinkage crack, such cracks usually occur before the initial vibrating grouting material to the final set. Main measures as follows: 1, controlling water cement ( Glue) Ratio. Common grouting material water-cement ratio should be controlled in 0. Within 6, waterproof grouting material of water cement ratio should be controlled in 0. 55 or less. High strength grouting material of water-binder ratio shoulds not be too small, otherwise the grouting material of autogenous shrinkage is too big, also prone to cracking. 2, control slump. Pumping grouting material goods vertical component should be controlled in 180 mm to 200 mm, horizontal component should be controlled in 160 mm to 180 mm. 3, timely and effective maintenance, within 12 hours after grouting material casting must be maintained. For horizontal component should be used outside covering plastic film and hydrating the way of combining protection against external filling water evaporation. Column, wall type vertical component should be taken to plastic film or careless packages and a combination of the water.