Concrete should be maintained in time after pouring to avoid quality problems such as dry crack and insufficient strength. What basic requirements should be met for concrete maintenance?

1.混凝土的养护时间应符合下列规定：

1. The curing time of concrete shall meet the following requirements:

1）采用硅酸盐水泥、普通硅酸盐水泥或矿渣硅酸盐水泥配制的混凝土，不应少于7d；采用其他品种水泥时，养护时间应根据水泥性能确定；

1) When Portland cement, ordinary portland cement or slag Portland cement is used, the curing time shall not be less than 7 days;

2）采用缓凝型外加剂、大掺量矿物掺合料配制的混凝土，不应少于14d；

2) The concrete prepared with retarding admixture and large amount of mineral admixture shall not be less than 14 days;

3）抗渗混凝土、强度等级C60及以上的混凝土，不应少于14d；

3) Impermeable concrete and concrete with strength grade C60 or above shall not be less than 14d;

4）后浇带混凝土的养护时间不应少于14d；

4) The curing time of post cast concrete should not be less than 14 days;

5）地下室底层墙、柱和上部结构首层墙、柱宜适当增加养护时间；

5) The maintenance time of basement bottom wall and column and the first floor wall and column of superstructure should be increased appropriately;

6）基础大体积混凝土养护时间应根据施工方案确定。

6) The curing time of foundation mass concrete should be determined according to the construction scheme.

2.洒水养护应符合下列规定：

2. Watering maintenance shall meet the following requirements:

1）洒水养护宜在混凝土裸露表面覆盖麻袋或草帘后进行，也可采用直接洒水、蓄水等养护方式；洒水养护应保证商品混凝土处于湿润状态；

1) Watering curing should be carried out after covering the exposed surface of concrete with gunny bags or straw curtains, or direct watering, water storage and other curing methods can be adopted;

2）当日低温度低于5℃时，不应采用洒水养护。

2) When the low temperature is lower than 5 ℃ on that day, watering maintenance shall not be adopted.

3.覆盖养护应符合下列规定：

3. Covering maintenance shall meet the following requirements:

1）覆盖养护宜在混凝土裸露表面覆盖塑料薄膜、塑料薄膜加麻袋、塑料薄膜加草帘进行；

1) It is better to cover the exposed surface of concrete with plastic film, plastic film with sack and plastic film with straw curtain;

2）塑料薄膜应紧贴混凝土裸露表面，塑料薄膜内应保持有凝结水；

2) The plastic film should be close to the exposed surface of concrete, and there should be condensation water in the plastic film;

3）覆盖物应严密，覆盖物的层数应按施工方案确定。

3) The covering shall be tight, and the number of layers of the covering shall be determined according to the construction scheme.

4.喷涂养护剂养护应符合下列规定：

4. Spraying curing agent curing shall meet the following requirements:

1）应在混凝土裸露表面喷涂覆盖致密的养护剂进行养护；

1) The exposed surface of concrete shall be sprayed with dense curing agent for curing;

2）养护剂应均匀喷涂在结构构件表面，不得漏喷；养护剂应具有可靠的保湿效果，保湿效果可通过试验检验；

2) The curing agent shall be evenly sprayed on the surface of structural members without leakage; the curing agent shall have reliable moisturizing effect, which can pass the test;

3）养护剂使用方法应符合产品说明书的有关要求。

3) The application method of curing agent shall meet the relevant requirements of the product manual.

5.基础大体积混凝土裸露表面应采用覆盖养护方式

5. The exposed surface of foundation mass concrete should be covered and cured

当混凝土表面以内40mm～80mm位置的温度与环境温度的差值小于25℃时，可结束覆盖养护。覆盖养护结束但尚未到达养护时间要求时，可采用洒水养护方式直养护结束。

When the difference between the temperature of 40mm ~ 80mm within the concrete surface and the ambient temperature is less than 25 ℃, the covering curing can be ended. When the covering curing is over but the curing time is not up to the requirement, the watering curing method can be used until the curing is over.

6.柱、墙混凝土养护方法应符合下列规定：

6. The curing method of column and wall concrete shall meet the following requirements:

1）地下室底层和上部结构首层柱、墙混凝土带模养护时间，不宜少于3d；带模养护结束后可采用洒水养护方式继续养护，必要时也可采用覆盖养护或喷涂养护剂养护方式继续养护；

1) The curing time of concrete with formwork for the first floor column and wall of basement and superstructure should not be less than 3 days; after the curing with formwork, the watering curing method can be used to continue the curing, and if necessary, the covering curing or spraying curing agent curing method can also be used to continue the curing;

2）其他部位柱、墙混凝土可采用洒水养护；必要时，也可采用覆盖养护或喷涂养护剂养护。

2) Other parts of column and wall concrete can be cured by sprinkling; if necessary, it can also be cured by covering or spraying curing agent.

7.混凝土强度达到1.2N/mm2前，不得在其上踩踏、堆放荷载、安装模板及支架。

7. Before the concrete strength reaches 1.2n/mm2, it is not allowed to step on it, stack load, install formwork and support.

8.同条件养护试件的养护条件应与实体结构部位养护条件相同，并应采取措施妥善保管。

8. The curing conditions of specimens under the same condition should be the same as that of the solid structure, and measures should be taken to keep them properly.

9.施工现场应具备混凝土标准试件制作条件，并应设置标准试件养护室或养护箱。标准试件养护应符合现行有关标准的规定。

9. The construction site should have the conditions for making standard concrete specimens, and the standard specimen curing room or curing box should be set up. The curing of standard specimens shall comply with the current relevant national standards.