Cracks controlling of compressor unit in large volume concrete under cold conditions

During the preliminary three to five days of casting completion of compressor unit in large volume concrete, the temperature difference between inside and outside of concrete excesses its ultimate because of the sudden temperature increase from the hydration heat of cement and the heat-insulating property of concrete together with the striking of the cold wave. In addition, the evaporation of the free and hydration water within the surface and the moisture evaporation on the surface of the concrete leads to the dry shrinkage-deformation. No measures taken, temperature and shrinkage stress can not be alleviated or decreased timely, and there is also a possibility to have hazardous temperature and shrinkage crack.Taking West-East natural gas transmission project as an example, with 5M1E as the analysis method (man, machine, material, method, measurement, environment) and focusing on construction and structure design, the following are discussed in detail: how to enhance the concrete pouring quality, control the concrete temperature rise, delay concrete cooling rate, reduce concrete shrinkage distortion, increase tensile strength of concrete, improve constraint condition of concrete, and strengthen temperature monitoring. And a series of effective techniques are analyzed and concluded, which can bring valid construction experience and economic returns in cold conditions.