| 摘要 |
Method for manufacturing a protective concrete weight coating for pipelines. The invention relates to materials for application to the outer surfaces of pipes as a protective negative buoyancy coating. It allows achieving accurately a desired density of the concrete protective weight coating of the pipeline in the range of 2600 to 3400 kg/m3 by claimed method of manufacturing a protective concrete weight coating for pipelines which includes mixing cement, aggregate, a plasticizing additive and water, pumping the resultant mixture into an annular space formed by the outer surface of a pipeline and a permanent form mounted With clearance thereon, and setting the resultant coating. In the method, Portland cement is supplied for mixing in an amount such that the mixture contains from 8.8 wt.% to 20.0 wt.% Portland cement, and water is added in an amount such that the ratio of water to cement is from 0.31 to 0.63. The plasticizing additive, in the form of a plasticizer and a defoamer, is supplied for mixing in an amount of from 1.0 kg/m3 to 3.0 kg/m3. The aggregate supplied for mixing is selected from barium ore or an iron-bearing ore, or gabbro-diabase, or granite With particle size not exceeding 10 mm. The resultant concrete mixture has a flow behaviour index, measured by the slump of a cone, which is equal to from 55 cm to 75 cm, and an air content of from 1% to 4% of the volume. |
