1. Basic principles: 

1. Keep the origin, variety and performance of various raw materials stable; 

2. Adopting sand with less mud content, reasonable thickness and reasonable classification will not increase the cost per cubic meter of concrete, but can reduce the cost; 

3. The cost can be reduced by adding fly ash, slag and other additives. Mixing concrete has better performance and lower cost, and the mixing ratio is determined by experiments; 

4. For medium and low quality concrete, the cost of ordinary water-reducing agent (DK-7) is lower than that of high-efficiency water-reducing agent (DK-4). 

2. Determine the experimental scheme: 

Take a cement mixed with fly ash and slag as an example 

1. Make reasonable mix ratio on the basis of preliminary test. Under other conditions unchanged, change the ratio of fly ash and slag, check the mechanical consistency and strength, and choose the appropriate ratio. In this way, the properties of fly ash and slag can be fully utilized. Through our experiments, it is proved that the optimal water consumption is the smallest and the intensity is the highest under the condition of constant export consistency. Of course, other ratios can be used if necessary. 

2.  Make a curve with cement consumption as the horizontal axis and strength as the vertical axis. 

3. Choose the blending ratio of the corresponding brand according to the table 

4. Select materials for retest and verification. 

5. In actual production, sample and count concrete strength to guide experiment and production. 

The department regulation is not favorable or the raw material performance is stable, but there are problems in the production link and production operation. 

If this happens, the reasons should be analyzed in time. If it cannot be changed in a short time, increase the insurance factor. 

6. When raw materials change, the concrete mixing ratio must be timely.