The maintenance of cement concrete floor is the last process in the construction workflow, which is often neglected or overlooked, and the quality of cement concrete floor maintenance determines whether the construction purpose can be achieved. Therefore, enough attention must be paid to ensure that the compressive strength, impact vibration, fatigue resistance, abrasion resistance, resistance to (salt) frost and durability of the cement concrete floor performance.
- The choice of curing method
Curing should begin immediately after the completion of the concrete floor. Mechanical paving of all kinds of concrete floors should be sprayed with curing agent and at the same time moisturizing cover way of maintenance. In rainy days or when there is sufficient water for curing, the wet curing method of sprinkling with water, such as covering with moisturizing film, geomat, geotextile, sack, straw bag, straw curtain, etc., can also be used. Should not be used to enclose water conservation methods.
- Requirements for spraying of conservation agents
When the concrete floor is cured by spraying curing agent, spraying should be uniform, film thickness should be sufficient to form a film that completely seals the water, and there should be no colour difference on the surface after spraying. The spraying time should be carried out after the concrete surface has finished secretion of water. The spraying height should be controlled at 0.5-1m. The minimum spraying dose should not be less than 0.3kg/m2 for Class I curing agent and 0.35kg/m2 for Qualified product. Do not use curing agent that can be easily washed away by rainwater, or have an impact on the strength and wear resistance of the concrete floor. When spraying a curing agent does not reach more than 90% of the effective rate of water retention, can be used to spray each of the two curing agent or spray a layer of curing agent and then cover the method.
- covering plastic film
The initial time of maintenance shall be determined by not crushing the fine anti-slip structure. The thickness of the film should be suitable, the width should be more than 600mm, when two films are connected, the width of the lap should not be less than 400mm, and the film should be kept complete and full during the maintenance period.
- Covering and maintenance
It is advisable to use moisturizing membrane, geotextile felt, geotextile cloth, sacks, straw bags, grass curtains and other coverings moisturizing maintenance and timely sprinkling of water, to keep the concrete surface always in a wet state, and thus determine the number of times a day sprinkling of water. Moisturizing membrane is a new type of curing material and way developed in 200 years in China, the bottom is water absorbing and moisturizing membrane, the top is black heat absorbing and water-insulating plastic film, the effect of heat preservation and moisturizing is very good. In the area where the temperature difference between day and night is more than 10 degrees or the average daily temperature is not more than 5 degrees, the maintenance measures of heat preservation and moisture preservation should be taken for the construction ground.
- The maintenance time
Maintenance time should be based on the growth of the compressive strength of the concrete ground, should not be less than 80% of the design compressive strength, should pay special attention to the first 7 days of moisture insulation maintenance. General maintenance days appropriate for 14-21 days, hot weather should not be less than 14 days, low humidity should not be less than 21 days. Mixing fly ash concrete ground more to strengthen the maintenance, the shortest time should not be less than 28 days, low temperature days should be extended. The maintenance requirements are for fly ash cement ground, only long-term maintenance of humidity to obtain a higher compressive strength later.
- maintenance of initial protection
At the initial stage of concrete ground maintenance, it is forbidden for people and vehicles to pass, and pedestrians can pass after reaching 40% of the design strength. During the period of ground maintenance, temporary bridges should be erected if passage is necessary.
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