The trial production was not running at full capacity. With a mixing capacity of 1.5 cubic meters, each plate only produced one side, so the first plate of concrete was mixed quickly, and the current was stable at about 75 amps.
Naturally, the slump of the concrete at this time cannot be determined yet. It can only be placed in the mixing truck and then sampled for testing.
While loading the materials, the engineer told Li Lei and others about the method of judging the slump of concrete through the magnitude of the current. If they compare it several times in the future, the difference will basically not be too much.
The first tray of concrete began to be unloaded. Li Lei and the other two operators ran to the unloading port to carefully observe the flow of concrete in the feed hopper of the concrete mixer truck to determine the slump of the concrete.
size.
Zhang Jianzhong, the director of the laboratory, also stood aside and asked with a smile: "Li Lei, Luo Lianghua, Huang Shuming, all three of you, please judge the slump of this plate of concrete. Let's see who can judge more accurately!"
Li Lei smiled and said: "Then I'll go first, I think it should be 140 millimeters!"
Luo Lianghua continued: "I don't think it's that much, at most 120 millimeters."
Huang Shuming was the last one to come. He had only been at work for two days. At this time, he could only say in a daze: "Then I will be one hundred and thirty, among you!"
Zhang Jianzhong smiled and said: "Okay, you will know next if your judgment is accurate or not."
Li Lei still stayed on top. Luo Lianghua and Huang Shuming followed Zhang Jianzhong down. Xiaopang had already pushed the bucket truck behind the concrete mixer truck, but he didn't dare to release the material because he had never done it before.
Zhang Jianzhong took it upon himself to quickly rotate the mixing drum for half a minute, and then pushed the handle to the reverse discharging position. At this time, the mixing drum began to reverse.
Zhang Jianzhong stared at the discharge port and said: "Everyone must pay attention to the uniformity of sampling when discharging materials in the future. Before discharging materials, the mixing drum must be quickly reversed to allow the concrete in the car to be mixed evenly and then reversed to discharge.
When discharging the material, you need to pay attention. When the concrete comes out, you must grasp the correct time to avoid discharging too much material and overturning the bucket truck. The concrete spilled on the ground is difficult to dispose of. "
In addition to these, there are also relevant regulations for sampling. For example, the sampling volume must be 1.5 times the test volume. Director Zhang Jianzhong is indeed a veteran and has very good control. A small half-truck truck of concrete has been placed.
Xiao Pang, Luo Lianghua and Huang Shuming worked together to quickly complete the concrete slump test. The result was 150 millimeters. It seemed that Li Lei's judgment was the closest.
Zhang Jianzhong smiled and said: "Luo Lianghua, Huang Shuming, it seems that the two of you are not as good as Li Lei, but it doesn't matter. This is your first time. As long as you watch more and do more, you will soon be able to use your eyes very accurately."
Determine the slump of concrete. There are many skilled operators who can basically judge it by looking at the current and listening to the sound. I believe you will soon master this basic skill!"
Luo Lianghua and Huang Shuming looked at each other and said in unison: "My director!"
Zhang Jianzhong said: "What we are going to pour today is the floor, so the current slump of 150 mm is too high. We want it to be below 100 mm, so that the quality of the floor can be guaranteed. For ground or road concrete
Generally speaking, the slump must not be too large. From a quality point of view, the smaller the better, but if it is too small, workers will be tired to operate it, so about 100 mm is more suitable. You all need to
remember."
Everyone hurried back to the operation room, because the second set of concrete still had to be produced. Whether it needed to be adjusted or not, they had to listen to the instructions of the laboratory.
Zhang Jianzhong came up and said to the factory engineer: "Gong Liu, the slump of the first plate of concrete is a bit too high. The test result is 150 millimeters. We need to control it at around 100 millimeters. The next plate of concrete will have a slump of less than 15 millimeters."
Kilograms of water! Add fifteen kilograms of sand."
Liu Gong smiled and said: "Okay, Director Zhang, let's see the results later!"
Production started on the second set. Zhang Jianzhong said to Li Lei: "Li Lei, your judgment was the most accurate on the first set of concrete just now. Come on. Let's look at the second set. If you encounter slump deviation during operation in the future,
If it is too large, the water consumption must be adjusted in time. Especially when the slump is too large, you must respond quickly and deduct water immediately, because in the future, formal production will be continuous and it is impossible to do it one plate at a time like now.
Adjust the disk!"
Li Lei nodded and said: "Director, I understand. Now that our second plate of concrete has been soaked with water, the slump has become smaller. After putting it in the mixer truck and mixing it with the first plate of concrete, it can be neutralized.
It’s a while, right?”
Zhang Jianzhong smiled and said: "Yes, if the slump of our second plate of concrete is 100 millimeters, then it should be about 120 millimeters after neutralization. We still have five plates of concrete. Theoretically, if the slump of each subsequent plate
The concrete is all 100 millimeters, so after the last truck of concrete is evenly mixed, it will have a slump of 110. Of course, this is theoretically, but in fact there will still be discrepancies. This includes when we do the slump
, there will be experimental errors, for example, if the same person operates, there may be a deviation of more than ten millimeters, and the same is true if another person does it."
The three operators were all new, so when they heard this, they quickly thought about it in their minds and tried to remember it, because they would soon be on duty.
Zhang Jianzhong continued: "In actual production, we will consider the distance of the construction site and set the slump of our out-of-machine concrete. For example, if we are pouring on our own site today, then there will be no problem of concrete slump loss.
.In the future, it will be delivered to the construction site. If the transportation distance is relatively long and the transportation time is long, then there will be a slump loss. Under normal circumstances, the slump loss we allow is a loss of 30 mm per hour. This
It is related to the quality of raw materials and the weather. It is a very complex issue. Generally, we will consider distant construction sites and the slump of the machine will be ten to twenty millimeters greater than the slump required by the customer. Of course,
The actual situation will need to be adjusted based on on-site feedback!”
It’s hard for Zhang Jianzhong to say too much. After all, people’s ability to accept is limited. If he talks too much, new operators will not be able to remember it. They have not yet intuitively understood the performance of concrete, so they can only take their time.
The second plate of concrete was mixed quickly, and the current of the main unit was indeed much greater than that of the first plate, reaching about 85 amps. Li Lei silently wrote all this down in his mind, because he was waiting for him to operate it.