JPH0623441B2 - Roadbed material - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention is an invention for effectively reclaiming the rest of ready-mixed concrete, which is industrial waste generated from ready-mixed concrete factories, so-called return ready-mixed concrete, as roadbed material for roads. Regarding

[Prior art and problems]

Conventionally, a large amount of raw concrete remaining in civil engineering and construction work is currently used as industrial waste for land reclamation or illegally dumped in vacant land, etc., which is a major company problem due to destruction of nature and living environment. It was.

Therefore, we try to reuse the recycled ready-mixed concrete without discarding it, for example, a large block (weight 500 kg) is manufactured from the returned ready-mixed concrete to process the returned fresh-mixed concrete, but there was a limit.

In other words, even if a large number of large blocks are produced in a large amount, there are few places where they can be used without a yard, and they cannot be sold as secondary products. In addition, the ready-mixed concrete is overmixed and its strength is low, and it is not accepted for block construction in public works.

Further, if the unsolidified returned green concrete is left as it is, it is hard to treat it, and the unsolidified and solidified returned raw concrete is difficult to process.

Although some methods of separating and recovering crushed stones, sand, and cement of such recycled ready-mixed concrete and reusing them as ready-mixed concrete are also used, not only is the recovery cost bulky and uneconomical, but also crushed stone and sand However, even if it can be separated and recovered, the cement content still remains, and it is difficult to completely remove the cement content from sand and crushed stone, and therefore, it has been extremely difficult to dispose of the recycled concrete.

Therefore, the conventional recycled ready-mixed concrete brings problems such as illegal dumping of industrial waste and destruction of natural environment and living environment.

[Object of the Invention]

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a roadbed material in which the recycled green concrete is utilized as a roadbed material and the effective use thereof can be achieved.

[Main points of the invention]

According to the present invention, the above-mentioned object was obtained by mixing the raw material of the cement, the crushed stone, and the sand, which was left after the cement was washed off, and the stone powder of the raised coral reef limestone, in a ratio of 3: 7 to 7: 3. It is achieved by a roadbed material characterized in that

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.

Usually, the ready-mixed concrete shipped from the ready-mixed concrete plant is crushed stone, sand,
The cement is mixed in a ratio of 4: 2: 1. This raw concrete is used in the field, and the cement is washed from the remaining raw concrete that has not been used up, that is, the returned raw concrete or the returned concrete, as described later in Fig. 2, and the crushed powder (stone powder or sink coral) of Ryukyu limestone (raised coral reef limestone) is washed. (Hereinafter referred to as coral), and mixed. The ratio of washed back concrete to coral is 3: 7.

Here, coral is a coral reef rock.
frocks) refers to marine limestone. It is commonly called "Ishigu" and is composed of fine particles (calcium powder) to large-sized lumps. It is called coral because it is a rock made of coral reefs.

Next, the chemical composition of coral is shown, though it differs slightly depending on the collection area, but its typical chemical composition.

When the roadbed material constructed as described above is used for road asphalt pavement as shown in FIG. 1, the soil 4 is cut or filled, and the ground is compacted by a large roller, compacted, and then fixed to a predetermined size. The roadbed material, which will be described later, is laid with a grader to the design thickness, and the work is similarly compacted by roller compaction to finish the lower layer roadbed 3, and then a crusher run with a predetermined design thickness (crushed stones to the required particle size). The surface layer roadbed 1 is formed by laying the ground material) and rolling the rollers to finish the upper layer roadbed 2 and laying asphalt on it to perform the roller compaction.

FIG. 2 shows a step of washing the cement component from the recycled green concrete and adding coral.

The ready-mixed concrete shipped from the ready-mixed concrete factory is transported to the construction site and placed there. The remaining casted material is used as return concrete, and the cement component washed at the return ready-mixed concrete washing place is washed away.

The ready-mixed concrete from which the cement content has been washed away is transported by truck and unloaded in the next step.

On the other hand, coral (stone dust) is mined in a coral mine, transported by a truck, and transported to the unloading site for the above-mentioned return ready-mixed concrete. The coral and ready-mixed concrete carried to each unloading place are carried to each material measuring device by the belt conveyor and mixed by a mixing mixer at a predetermined ratio.
The washed green concrete, that is, the roadbed material in which crushed stone and sand are mixed with coral, is laid so as to form the lower roadbed 3 of the road having the cross-section shown in FIG.

In the embodiment of the present invention described above, the mixing ratio of the return concrete and the coral is shown as 3: 7.
This can be changed according to the difference in composition depending on the coral extraction area used, the water passage rate of the road and other conditions as described above. For example, the mixing ratio of return concrete and coral is 3: 7 to 7: 3. The present invention can be implemented even in such a case.

〔The invention's effect〕

According to the roadbed material of the present invention configured as described above, it is possible to effectively use the return concrete that has been conventionally industrial waste, and the wear resistance and CBR are significantly improved as compared with the conventional roadbed material.

[Brief description of drawings]

 FIG. 1 is a general road sectional view when used as a roadbed material, and FIG. 2 is a manufacturing process drawing. 1 ... Surface roadbed (asphalt), 2 ... Upper roadbed (crusher run), 3 ... Lower roadbed (roadbed material), 4 ... Soil.

Claims (1)

[Claims] 1. A residual material remaining after washing away cement by washing fresh concrete consisting of cement, crushed stone and sand.
Roadbed material characterized by mixing up to coral reef limestone stone powder in a ratio of 3: 7 to 7: 3.