Speaking of concrete machinery, I believe that everyone is no stranger, pump car, car pump, mixer, pump, mixing station and so on, well known. With the acquisition of European manufacturers by 31, Xugong and CCP, China has been in the world's leading position in the field of concrete machinery. But have you ever thought about how to carry out concrete construction before these machines are widely used?
Some people may still remember the past, often in the construction site to see the scene with a stirring barrel type mixer drag, there will be workers sifting the sand beside a wheelbarrow, gravel, sand, cement will be poured into the mixer, water for mixing, and then after the completion of the trolley will be concrete and pour away the position then, vibratortamping, finally disappearing, covered with straw water conservation.
The above construction method which lacks quality control has been gradually banned. Now it can be seen only in some unsupervised building occasions, such as building houses in rural areas. Regular buildings in the state of regulation usually have to use commercial concrete, using a mixer and a pump truck to direct the concrete directly into the position. And this method is only about thirty years in China.
However, the above two kinds of construction methods, whether the mic is tall on, there is a problem, unable to cope with the construction of high strength concrete. For example, what should a large hydropower project be done if you have to pour 1~2 ten thousand square meters of concrete every day and continue for a few months? If only for a while, for example, some large buildings need to pour tens of thousands of concrete in dozens of hours, we can mobilize hundreds of equipment for construction, but obviously we can't do this for a long time.
So how did the large hydropower projects work twenty or thirty years ago? There were not so many pumps at that time, but they didn't use the pump before. In the past, there are only two kinds of traditional concrete machinery, one is mixing equipment, the other is vibrating equipment, and the transportation links in the middle are not concrete machinery.
Because the past concrete has no fixed and standardized means of transportation, in order to meet the requirements of large volume concrete placement, the most commonly used means of transportation include two kinds, one is horizontal transportation, the other is vertical transportation. Horizontal transportation can be loaded by trains and cars at large mixing stations, and transported to buildings nearby, and then transported vertically by crane. The concrete will be lifted to the upper part of the warehouse. A concrete container can be a vertical tank, a horizontal tank, or a truck for a dump car. The vertical tank can be used to transport the train, with a crane hanging directly to the position, open the door will be poured, horizontal tank is usually matched with a dump truck, a crane and a horizontal tank is not decoupled, on the ground, the dump truck unloading tank directly expected, lifted into position by crane. Another way of both horizontal and vertical transportation is a cable crane, like a cableway.
Later, with the emergence of roller compacted concrete, because of the poor fluidity of concrete, it could not be reused, so the construction method changed to self unloading vehicle, which was directly opened into the warehouse and discharged. It was closed by bulldozers and rolled by roller. Of course, RCC is used only for specific occasions, and this method can not be used in general construction engineering.
In the Three Gorges project, with a generous amount of conventional concrete, RCC has a generous amount, and construction requirements of high intensity, the traditional methods can not guarantee the construction of long-term high intensity, it was specially introduced the tower belt machine, belt machine to realize the horizontal and vertical transportation. The combination of tower crane and conventional method has finally created the record of the highest concrete pouring intensity of the 22 thousand party, the highest intensity of 550 thousand sides and the annual pouring intensity of 4 million.
Of course, most of the building project is far less than the intensity of this construction, can meet the demand for the concrete pump truck, the characteristics of concrete pump truck is saved by a crane to vertical transportation, crane efficiency is high, so it is widely used in construction, out of the way and concrete crane tank systems.
