Li Liangfeng's hands and feet are quite sharp, and he quickly sifted out the gradation of sand and gravel samples sent by Manager Wu, and after calculation, the results met the requirements, after all, the sand and gravel resources are sufficient now, so there are still relatively few unqualified sand and gravel, not to mention the samples.

Qin Haijuan looked at the grading situation, nodded and smiled: "Manager Wu, your samples are okay, but we will organize personnel from relevant departments to inspect your company's sand mining site and gravel production base at that time, on the one hand, to see the actual quality of your materials, and on the other hand, to see whether your supply capacity meets our needs." ”

Manager Wu laughed and said: "Welcome, we raise our hands to welcome you experts to visit us to inspect and guide the work, to be honest, we feel that if the two sides can reach cooperation, it is not a problem, and we can also produce according to your requirements." ”

Qin Haijuan said with a smile: "Manager Wu said very well, our concrete production enterprises are to link up with raw material enterprises in order to make concrete better." As far as the aggregate composite structure is concerned, there are three types: suspension dense structure, skeleton dense structure and skeleton void structure, which correspond to substrate cementation, pore cementation and contact cementation in rocks. Different concrete has different structural requirements for the skeleton. For pumped concrete, a relatively dense and easy-to-flow aggregate combination of suspended dense structure is required, for dry hard and plastic concrete, a combination of dense aggregates is required, and for permeable concrete, a skeleton void structure is required. ”

Manager Wu was stunned when he heard this, and couldn't help but sigh that he had read too little, and he didn't understand anything in front of such an expert.

Qin Haijuan smiled again: "Actually, aggregates are also adjustable and controllable in your raw material manufacturers, and the gradation of a certain aggregate is a definite continuous particle size or a single grain size. The aggregates needed for production are to synthesize an aggregate combination with a new gradation from the existing aggregates. There are several ways to do this. ”

Manager Wu took out his notebook and said, "Ah, Director Qin, wait for me to remember it, I will definitely talk to the boss about this when I go back, and we must also improve our technical level." ”

Li Liangfeng also took advantage of his free time to do experiments and listened to Qin Haijuan.

Qin Haijuan said: "The first method is to combine aggregates in different proportions, measure their bulk density separately, and take the denser ones. Generally, the proportion of various sand and stone is determined separately, and then the sand rate is determined according to experience or other methods. That is, the result is compact, but it is uncertain whether it is suitable for the formulation of pumped concrete. It is convenient to synthesize 2 types of sand or stone, but if there are more than 3 types, the test will be more complicated. Then you need to synthesize two of them first, and then use them as particles and the third type to synthesize them. ”

"The second method is to solve the problem directly from the sieving results according to the continuous gradation curve. Aggregates are combined according to different proportions, and the sieving residue of each grade is calculated separately to meet the continuous gradation. As with method 1, the stone and sand are first matched according to the grading range in the specification, and then the sand rate is selected. ”

"The third method determines the dosage of the next gear according to the porosity of the previous gear, which is the one with a larger particle size. It is also necessary to determine the proportion of various stones first, and then determine the sand rate. For example, the volume of "dry mortar" is used to fill the stone void and other positive filling methods and reverse filling methods. There is also a unified curve of sand and gravel based on continuous gradation, based on the fact that sand and stone are aggregates, but the difference between coarse and fine particles and the particle size junction of stone and sand respectively will have a great possibility of collision, and the sand and stone should be considered in a unified manner to simplify and optimize the method of synthetic aggregate gradation. ”

After Qin Haijuan finished speaking, Li Liangfeng couldn't help but begin to admire this female boss, she was indeed very knowledgeable.

Li Liangfeng began to do the mud content index again, at this time Manager Wu also wrote down what Qin Haijuan said, this guy was full of smiles, he was completely a sycophant, but he needed this kind of person to do sales, even Qin Haijuan was unconsciously praised by him a little fluttering, and his favorability towards this guy also increased.

At this time, Manager Wu said: "Director Qin, don't worry, our company's materials ensure the quality, especially the mud content, we will also strictly control the materials, and we will resolutely not send you the mixing plant for bad materials." ”

Qin Haijuan nodded and said: "That's good, if that's the case, the probability of your company winning the bid is still very high, and in several companies, you are not bad." Because the sand and gravel are mostly natural local materials, the material often changes with the different conditions, such as the cause, origin, collection, and storage, and often encounters poor grading, excessive mud content, and more crushed stone needles. Mud content is an important indicator of sand and gravel materials, tiny particles greatly increase the specific surface area of powder, unilateral water consumption is greatly improved, strength can not meet the requirements, it is necessary to increase the amount of admixtures, thereby increasing the cost of concrete. Excessive mud content will reduce the bond strength of the concrete aggregate interface and reduce the tensile strength of the concrete, which will affect the strength and durability of the concrete, and will also cause the peeling and cracking of the concrete itself, which will bring immeasurable losses to the quality of the project. In addition, the mud content in the sand and gravel is too much, and the slump of the fresh concrete is reduced accordingly, if the slump of the concrete is required to be the same, the water consumption will inevitably increase, so that the amount of cement will be increased or the amount of admixture will be increased accordingly, and the cost of concrete will be increased in a large way. Therefore, we will strictly control the sand and gravel materials entering the site, and we will resolutely return those that are unqualified, which you must be mentally prepared for. ”

Manager Wu said with a smile on his face: "Director Qin, I completely agree with your opinion!" We will also strengthen the control, if you find substandard materials, whether it is sand or stones, you call me, I promise to severely punish the irresponsible. Hehe, the customer is our God, and we are absolutely honest. ”

Qin Haijuan nodded and said: "That's good, we are afraid of meeting that kind of supplier, the material is not qualified, he also went to the general manager of the concrete batching plant or a higher floor, saying that our technical quality department wants to eat and take cards, so it is very bad, we are completely in accordance with the company's regulations and the principle of the quality management system to accept the material, to detect the number of jù to speak, is absolutely not nonsense to say that the material is unqualified, to return the like." ”

Manager Wu said with a smile: "That's, that's, I fully believe in Director Qin, and experts like Li Gong, in front of experts, I absolutely believe it." You call me directly if you have a problem, okay? (To be continued.) )