JPS62202171A - Novel construction method for spraying mortar or concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Fields of Use The present invention is useful for protecting cut surfaces resulting from civil engineering work, slopes such as bare areas on desolate mountainsides, walls during tunnel excavation, and for protecting pillars and bridges. Regarding the mortar or concrete spraying method, which is often used for placing mortar or concrete in construction projects, we have developed a new method that can efficiently cast mortar or concrete with strength several times higher than the current method. Related to spraying method.

Conventional techniques The conventional methods for spraying mortar or concrete include the wet spraying method, in which sand or a mixture of sand and gravel with cement and water is sprayed onto a predetermined location via a transport hose, and the wet spraying method, in which cement is mixed with sand or sand and gravel. A dry spraying method is used in which a material is sprayed onto a predetermined location via a transportation hose, and water is ejected in the form of a spray from the tip of the spray nozzle to mix with the sprayed material.

Problems to be Solved by the Invention However, especially when trying to transport a mixture of water via a hose as in the wet spraying method, the water ratio in the mixture tends to be too high in order to facilitate transport. ,
As a result, there are drawbacks such as a decrease in the strength of the cast mortar or concrete after hardening, and a tendency to shrink and crack after hardening.

In addition, in the dry spraying method, it is possible to reduce the moisture ratio in mortar or concrete by adjusting the amount of water to be mixed in the form of a spray, but when cement is mixed with sand that is actually used as aggregate, The problem is that the water naturally contained in the sand wets the cement and forms a clay-like plastic substance, which can clog transportation hoses or reduce the inner diameter of the hose, making it difficult to perform smooth spraying operations. There is.

The purpose of the present invention is to solve all of the drawbacks and difficulties in the mortar or concrete spraying work, and to make it possible to efficiently cast mortar or concrete with high quality after hardening. do.

Means and operation for solving the problems The present invention provides a mortar or concrete characterized in that a mixture of cement and sand with frozen water content or aggregate containing the sand is sprayed as mortar or concrete. This is a concrete spraying method.

In general, sand used as aggregate for mortar or concrete, regardless of whether it is mountain sand, river sand, or sea sand, usually contains about 10 to 20 inches of water. Therefore, considering the current mixing ratio of cement and aggregate for ordinary mortar or concrete, if the mixing of cement and sand can be done sufficiently homogeneously and intimately, it will be possible to do so without adding water separately. The water contained in the sand can satisfy the water/cement ratio required for the production of cement paste, and on the other hand, the water/cement ratio in this case is much smaller than that in current ordinary mortar or concrete. Therefore, high quality mortar or concrete with high pressure a strength after curing should be obtained.

The present invention has been made with attention to such circumstances, and as mentioned above, in the present invention, the water contained in the sand used as aggregate is frozen using an appropriate refrigerator or the like, and then the water is frozen. Since the method of mixing sand and cement is adopted, the mixing of sand, water and cement is a process of mixing solid powder and granules with soil without the involvement of liquid water, resulting in homogeneous and intimate mixing. This also eliminates the generation of clay-like plastic substances due to the interaction between liquid water in the sand and cement, allowing for smooth spraying operations without accidents such as clogging transportation hoses and equipment. You will be able to do it.

Furthermore, as the water content in the frozen sand naturally melts in the mortar or concrete that has been poured, it acts on the surrounding cement to produce cement paste, and over time, the mortar or concrete hardens completely. However, since the water content that makes up the cement glue in the mortar or concrete is essentially limited to the water contained in the sand, the mixing ratio of 70%, 70% and aggregate is not the same as the current standard. In the range where the water/cement ratio is much lower than that of current mortar or concrete, mortar or concrete with extremely high compressive strength after hardening can be obtained, and it will not shrink after drying. This makes it possible to obtain mortar or concrete that is less prone to undesirable phenomena such as cracking.

In addition, when the water content in the sand is too low and there is insufficient water for cement paste production, such as in the case of sand that is too dry, water may be sprinkled on the sand to freeze the water content in the sand. Of course, it is also possible to take measures to appropriately increase the moisture content in advance.

Example 1 Mountain sand with a water content of 10 to 20% is frozen to freeze the water content, and then cement is mixed with the sand according to the sand and cement ratio of current normal spray mortar, and mixed homogeneously. By doing so, a free-flowing powder-like mortar is obtained. Then, the mortar is sprayed onto the mountainside cut slope via a transportation hose using pressurized air, deposited on the slope to an appropriate thickness, and allowed to cure, resulting in natural melting of the water content in the frozen sand. A cement paste is formed by the interaction with the surrounding cement, and then, over time, the entire mortar hardens.

Example 2 Concrete A mixture of gravel mixed according to the current normal spray m ratio and sand with a water content of 10 to 20% is frozen to freeze the water content in the sand. During spraying, cement is added to the mixture according to a predetermined mixing ratio and mixed homogeneously to obtain granular concrete. Then, the granular concrete IJ-t is sprayed and poured via a transport hose using pressurized air to form floor slabs for building construction, and is then allowed to cure, thereby reducing the amount of water that freezes in the sand. The entire concrete is hardened through melting and subsequent reaction with the surrounding cement.

Effects of the Invention As is clear from the above description, the mortar or concrete IJ-spraying method of the present invention has the following advantages: (1) Moisture contained in sand in its natural state is used to make cement paste; mixing mortar or concrete;
There is no need to add water during production, making it easy to keep the workplace tidy. Mixing and manufacturing of mortar or concrete does not require the presence of liquid water and the powder and granules are mixed together on the same soil, so there is no need to mix between each component. This makes it easy to homogeneously and intimately mix the cement, making it possible to obtain high-quality mortar or concrete. C. Since there is no liquid water during the production of mortar or concrete, the wetting action of the liquid water in the cement is Therefore, the formation of clay-like plastic substances is eliminated, reducing problems such as clogging in transportation hoses and other equipment, making it easier to transport to distant or high places, and ensuring smooth transportation over long periods of time. 2. Since the water/cement ratio can be kept small, it is possible to obtain mortar or comfleet that has high strength and is less likely to shrink or crack after hardening. It has a significantly useful effect in terms of pouring technology.

Claims (1)

[Claims] 1. A mortar or concrete spraying method characterized by spraying a mixture of cement and sand with frozen water content, or aggregate containing the sand, as mortar or concrete.