When Li Ruoyu said this, Li Liangfeng calculated the amount of trial materials just right, and handed a stack of materials to Li Ruoyu.

Li Ruoyu took the calculation data, looked at it twice, and handed it to Xie Zili.

Xie Zili looked at it and said, "Okay, basically there is no problem, then let's start the trial!" Li Liangfeng, you are responsible for weighing sand and gravel, and Director Qin, you are responsible for weighing cementitious materials and admixtures, as well as water. ”

Li Liangfeng and Qin Haijuan began to start when they heard the words, trial matching is a physical work, fortunately, Li Liangfeng was originally a farmer's child, Qin Haijuan also did a lot of trial matching in the concrete technology research and development center, so the two of them cooperated, but there was still some tacit understanding, and soon the first concrete trial materials were weighed.

This plate of concrete is 25 liters, the weight of all materials adds up to about 60 kilograms, sand and gravel accounts for about 70 percent, weighing 40 kilograms, plus the iron bucket containing sand and gravel is afraid of no less than 50 kilograms.

Of course, a delicate girl like Qin Haijuan can't do it, so this kind of work can only be done by Li Liangfeng.

Li Liangfeng poured the sand and rubber into the single-shaft compulsory mixer used for the test, and then Qin Haijuan picked up the water and admixture and started the mixer, and then poured water and admixture into it.

Li Ruoyu said on the side: "Pay attention to the admixture, don't finish adding, leave a little to see if the dosage is appropriate." Of course, we don't want the first tray of concrete. In the future, you should also pay attention to the trial matching, because there will be a lot of mortar stuck to the inner wall of the mixer, the mixing shaft and the blades of the first tray of concrete, so the test results of the first tray of concrete must have a big error. This is equivalent to moistening the pot with the first plate of concrete, and of course it is also possible to use the same mix mortar. ”

Qin Haijuan nodded and said, "Okay, Mr. Li." ”

As the sand, gravel cement and fly ash are mixed evenly in the concrete mixer, the water and admixtures also go down, and you can see that the material in the mixer slowly turns into flowing concrete.

After the failure last time, the adjusted mix ratio this time is basically more accurate, Qin Haijuan has added water and admixtures, and the working performance of the concrete looks good.

Stir for two minutes. Qin Haijuan looked at it, so she pressed the stop button, the mixer stopped rotating, and at this time Li Liangfeng stepped forward. Step on the circlip with your foot, then turn the mixing pot over one by one, then release the circlip again to fix the mixing pot.

When it is clicked again, the concrete in the pot is turned out. Well, it doesn't look good, because there is more mortar stuck in the mixer in the first plate, if you use this concrete for testing, the error will definitely be relatively large, and the concrete strength will be much lower than the normal value.

Li Liangfeng shoveled the first pot of concrete aside, and then continued to weigh the materials of the C15 concrete mix test.

Sure enough, the remixed C15 concrete looks much better than it did before, although the C15 concrete itself has less cementitious material. It doesn't look like the slurry is too rich, but it's okay to meet the pumping.

The next step is to test the working properties of the concrete mixture.

Li Ruoyu asked: "Li Liangfeng, you have also learned the relevant specifications, now you can talk about the purpose and scope of application of our concrete mixture test." ”

Li Liangfeng had already memorized the standards well, and he replied without thinking about it: "In order to control the quality of concrete engineering and test the various properties and quality and rheological characteristics of concrete mixtures, it is required to uniformly follow the performance test methods of concrete mixtures, so as to test the basic properties of concrete mixtures used in industrial and civil buildings and general structures." For the performance test of concrete mixture, we mainly do several items in the trial, first of all, the workability of concrete! ”

Li Ruoyu smiled and said, "That's a good answer." Then I'll ask again. What is the workability of concrete? ”

Li Liangfeng nodded and said: "The property that indicates the difficulty of construction and operation of the concrete mixture and the resistance to segregation is called workability. Workability is a general concept composed of properties such as fluidity, cohesion, and water retention. Fluidity, also known as consistency, refers to the performance of the concrete mixture in all corners under its own weight or the vibration of construction machinery, which can produce flow and uniform and dense filling formwork. If the liquidity is good, it is easy to operate. It is easy to vibrate and form. Cohesiveness means that the concrete mixture has a certain degree of cohesion between each other during the construction process, does not stratify, and can maintain the overall uniform performance. Water retention refers to the ability of concrete mixture to retain water that is not easy to precipitate. ”

Li Ruoyu smiled: "Okay, the answer is correct." It is also stated in the specification that the test of concrete mixture should be carried out as much as possible. Before the test. The sample should be slightly stirred manually to ensure its uniform quality. It should not take more than 5 minutes from the completion of sample preparation to the start of various performance tests, so now you and Director Qin should cooperate to do the slump test. ”

Li Liangfeng nodded when he heard this, then picked up the shovel and mixed the concrete back and forth more than a dozen times according to the standard, so that the concrete on the ground became relatively uniform.

Qin Haijuan moistened the steel plate ground with a towchief on the side, and then moistened the slump bucket with wet hair, in front of Li Ruoyu, their movements were all cautious, for fear of making a mistake.

At this time, Xie Zili smiled and said: "Director Qin, let's come, a beautiful girl like you comes to make concrete, but I'm afraid that my hands will become thick." ”

After speaking, Xie Zili didn't care about Qin Haijuan's insistence, so he snatched the slump bucket, and then stepped on the two ears of the slump bucket with his feet.

With a funnel on top of the slump bucket, Xie Zili said, "Li Liangfeng, let's start loading concrete." ”

Li Liangfeng began to evenly load the concrete samples into the cylinder in three layers with a small shovel according to the method specified in the standard, and the height of the first layer was about one-third of the height of the cylinder.

After installing the first layer, Xie Zili picked up the tamper and began to insert the rod, the rod was inserted along the spiral direction from the outside to the center, Xie Zili's insertion action was very standard, just twenty-five times, and the distribution was also very uniform in the entire section. When inserting the concrete on the edge of the barrel, the tamper in his hand was slightly tilted; When inserting the bottom layer, the tamper also runs through the entire depth.

Li Liangfeng then installed the second layer of concrete, Xie Zili inserted the second layer according to the method just now, and then the third layer, after the top layer was inserted, Li Liangfeng scraped off the excess concrete with a spatula, and then smoothed it, and scraped the concrete around the slump barrel to the side; Xie Zili also pressed the handle of the slump bucket with his hand, then removed his feet and slowly lifted the slump bucket. (To be continued.) )