In general, the homogeneity of concrete is improved with the extension of mixing time, but when the mixing time exceeds a certain limit, the homogeneity of concrete is not significantly improved. Therefore, the automatic concrete mixer should have strict requirements on mixing time, which is good for the quality and productivity of concrete. Following years of industry experience, Zhongke summarizes the requirements of concrete mixing time for your reference.

混凝土搅拌时间要求规定：

Concrete mixing time requirements:

一、人工搅拌：

1、 Manual mixing:

搅拌时力求动作敏捷，搅拌时间从加水时算起，应大致符合下列规定：

The stirring time should be calculated from the time of adding water, which should roughly meet the following
requirements:

搅拌物体积为30L以下时4~5min(分钟）

4 ~ 5min (min) when the volume of mixture is less than 30L

搅拌物体积为30L--50L时5~9min

5 ~ 9min when the volume of mixture is 30l-50l

搅拌物体积为51L--75L时9~12min

When the volume of the mixture is 51l-75l, it takes 9-12min

拌好后，根据试验要求，立即做坍落度测定或试件成型。从开始加水时算起，全部操作须在30min内完成。

After mixing, according to the test requirements, slump measurement or specimen molding shall be conducted immediately. From the beginning of adding water, all operations must be completed within 30 minutes.

二、机械搅拌：

2、 Mechanical mixing:

先预拌一次，即先涮膛，以免正式拌和时影响拌合物的配合比。开动搅拌机，向搅拌机内依次加入石子、砂和水泥，干拌均匀，再将水徐徐加入，全部加料时间不超过2min,水全部加入后，继续拌和2min。

Premix first, that is, rinse the chamber first, so as not to affect the mix proportion of the mixture during formal mixing. Start the mixer, add stones, sand and cement to the mixer in turn, dry mix evenly, and then add water slowly. The total feeding time shall not exceed 2 min. after all water is added, continue to mix for 2 min.

将拌合物自搅拌机卸出，倾倒在拌打捞上，再经人工拌和1~2min,即可做坍落度测定或试件成型。从开始加水时算起，全部操作一定在30min内完成。

The mixture is discharged from the mixer, dumped on the mixer, and then mixed by hand for 1 ~ 2min to measure the slump or form the specimen. From the beginning of adding water, all operations must be completed within 30 minutes.

以上分享的混凝土搅拌时间要求规定相信大家都已了解，大家不妨按照以上方法来规定搅拌时间或是用自己实验出来的佳时间来规定即可。

I believe you all know the concrete mixing time requirements shared above. You may as well specify the mixing time according to the above methods or use the good time from your own experiments.