In the process of concrete mixing, the confirmation of concrete mixing mix ratio is a crucial link, which is directly related to the quality, strength and durability of concrete. Mix ratio is to point to the proportion relationship between each component material in concrete (like water, cement, aggregate, admixture and admixture, etc.). The correct mix ratio can ensure that the concrete meets the performance of the design requirements, and the wrong mix ratio may lead to unqualified concrete quality, and even cause engineering accidents.

Procedure for mix ratio confirmation
Theoretical mix ratio design
Before mixing, the theoretical mix ratio of concrete is determined by calculation according to the engineering requirements, material properties and test data. This usually includes the amount of cement, water-cement ratio, aggregate grading and admixture, admixture type and dosage, etc.

Trial mixing and adjustment
Test mixing according to the theoretical mix ratio, observe the compatibility of concrete mixing material (including fluidity, adhesion and water retention), slump and other indicators. If it is found not to meet the requirements, the mix ratio should be adjusted in time and try to mix again until the design requirements are met.

Inspection during stirring

Material measurement: to ensure the accuracy of various raw materials in the mixing process, especially the amount of cement, water and admixture, because these materials have the most significant impact on the properties of concrete.

Mixing time: control the mixing time, to ensure that the concrete mixture is mixed evenly, to avoid the unmixing uniform mass or segregation phenomenon.

Slump detection: regularly test the slump of the concrete mixture, to determine whether its working performance is stable. If the slump is found to change greatly, the reason should be found in time and adjust the mix ratio.

Appearance inspection: observe the appearance of concrete mixing, check whether there is bleeding, segregation and other bad phenomena.

Sampling and testing
In the mixing process of mixing, regular samples should be taken from the mixer for concrete strength, impermeability, durability and other performance tests. These test results will be used as the basis for the rationality of the mix ratio.

Records and feedback
Record the change of mix ratio, inspection results and test results during the mixing process in detail, and timely feedback to relevant departments or personnel. If a problem is found in the mix ratio, it should be adjusted and re-confirmed in time.

matters need attention
The design and adjustment of the mix ratios shall be based on sufficient test data and engineering experience.

The quality and measurement accuracy of raw materials should be strictly controlled during the mixing process.

Maintain and maintain the mixing equipment regularly to ensure that it is in good working condition.

Strengthen the communication and coordination with the construction site, timely understand the use of concrete and feedback opinions.

Through the implementation of the above steps and matters needing attention, we can ensure that the mix ratio of concrete mix is accurately confirmed and effectively controlled, so as to ensure the quality and safety of concrete.