2. Coal-fired steam curing will produce a lot of harmful gases (carbon dioxide, sulfur dioxide, nitrogen oxides) and PM2.5 in the process of generating steam. Some large prefabricated beam yards need to invest a lot of money to build steam boiler rooms and arrange steam transportation pipes along the pedestal of the beam yard. The long transportation distance of steam pipeline also directly leads to large heat loss along the way, and the steam maintenance process needs 24-hour uninterrupted shifts.
3. Honeycomb coal stove is used for heat storage and maintenance. In this way, a number of small honeycomb briquette stoves are generally placed in the covered concrete, and the heat generated by burning coal stoves is used for heat storage and insulation, which has no effect on moisture retention, and more carbon monoxide gas is produced during combustion. The contact of carbon monoxide with the concrete surface will aggravate the carbonation of concrete, and the existence of carbon monoxide in the maintenance shed cover has great security risks for the construction workers entering the interior.
4. Hot water maintenance in winter. This method generally burns water to a certain temperature and then sprays it on the concrete surface through electric heating, which has a certain effect of heat preservation and moisture retention. However, with the loss of water, heat will be quickly dissipated, and some areas on the concrete surface may be stored and heated in time, and may freeze when the temperature drops.
5. Electric steam curing produces steam through electric heating, which is pollution-free. However, in the construction process, it is still necessary to manually control the start and stop, and judge whether to supply steam by manually measuring the temperature and humidity of maintenance. Therefore, the quality of maintenance has a great relationship with the sense of responsibility of operators, especially temperature measurement at night, which is difficult to implement, so it has great limitations.