Progress in stone block reinforcement technology

About 30% of the stone blocks are loose and porous, and the cracks are wide and deep. During the transportation of the blocks, especially in the process of sawing into the board, they are easily broken into waste rocks, causing huge waste of natural resources. Caused major economic losses. As natural marble resources continue to be mined, their resources are decreasing year by year. How to enhance the reinforcement of stone blocks and ensure smooth sawing to avoid waste of resources has become an urgent problem for stone mining and processing enterprises.

All along, the industry has explored and practiced many methods on how to strengthen the blocks to ensure the sawing rate. The author is here to make a sort of reference for the relevant technical colleagues to learn from.

Crack injection reinforcement

For the blockages with large cracks and obvious holes, most manufacturers use simple equipment such as syringes or grease guns to inject the glue into it, and it will play a certain role of bonding reinforcement after curing. Although the process operation is simple, it has the disadvantages of low efficiency and easy leakage of glue. It is more important that the penetration depth of the ordinary glue to the crack is limited, and the internal reinforcement effect of the block is not satisfactory, and the card saw often appears when sawing to the center of the block. Collapse. At the same time, this kind of reinforcement is powerless for narrow cracks or granular types of blocks (such as Altman).

2. External package reinforcement

External wrapping is a commonly used reinforcement method for stone companies. The usual practice is to apply a layer of unsaturated polyester resin (commonly known as resin glue) or epoxy resin (commonly known as AB glue) adhesive to the rinsed and dried blocks, and then attach the fiberglass mesh. Close it and finally apply a layer of adhesive to the surface. It can be placed on the saw after it is completely cured. The following is a comparison of two adhesives:

Comparative project unsaturated polyester resin epoxy resin

The construction method can be painted and sprayed

Larger smell

Low cost and medium

Colloidal strength is lower

As can be seen from the above table, unsaturated polyester resin glue is currently dominant in the block packaging market due to its low cost and flexible construction method, but its strength is low and brittle, although the industry has added nano-filler to improve the strength of the formulation. The modified nano-adhesive appears to increase the certain strength, but because it still contains a large amount of styrene as a diluent, the smell is large, which is not conducive to the health of the construction workers and has a great impact on the environment. In recent years, there has been a tendency to be replaced by epoxy resin. In foreign countries such as Turkey, Egypt and other stone producing countries, unsaturated polyester resin rubber has withdrawn from the parcel rubber market.

Through the surrounding parcel reinforcement, it can basically prevent the corners from falling and falling in the process of transportation, hoisting and sawing, and ensure the integrity of the blocks. However, for the inside of the block, especially the cracks with developed internal cracks have little effect. During the sawing process, due to the strong back and forth vibration of the saw blade, the inner cracks that originally loosely cracked will fall, which will still cause the card saw. Even the collapse phenomenon seriously affects normal production.

3. Vacuum impregnation reinforcement

According to the industry colleagues, domestic companies have introduced a new Italian vacuum impregnation reinforcement block production line. The patent WO2007054995 A1 filed by Roberto PUCCI of Italy reports the process in detail: firstly, the block to be reinforced is washed and dried, and then the reinforced glass fiber and the vacuum bag film are used to cover and seal the block, and the whole block can be fed into the block. In the closed tank, the air inside the vacuum bag film is extracted, and the glue is injected into the bag. After the glue is injected, the inside of the tank is filled with compressed air. The inside of the vacuum bag is also filled with positive pressure, but the pressure inside the tank is always greater than the vacuum bag. The pressure inside the membrane allows the glue to penetrate completely into the cracks inside the block. At the same time, the closed tank heating is accelerated and solidified, so that the block material has an excellent reinforcing effect from the inside to the outside. However, the process operation requires large special equipment to assist, the process is complicated, the efficiency is low, the glue requirement is high, and the cost is difficult to control (the initial cost of reinforcing a block material is about 10,000 yuan), and only a few varieties of blocks are applicable. Therefore, it has not been widely promoted.

4. High pressure infusion reinforcement

In recent years, many companies have done a lot of work in the field of block reinforcement. Among them, Hunan Kesheng New Materials Co., Ltd., a member unit, has continuously explored and innovated, broke the routine, and carried out extensive exploration and research on the reinforcement of blocks, and made breakthrough progress. The following highlights are the two latest block reinforcement methods developed and patented by the company – high pressure infusion and vacuum infusion reinforcement. It is reported that the technology has been used by many stone enterprises at home and abroad, and has won high praise from the stone industry.

High-pressure perfusion is a process in which a special glue is injected into the inside of the block by a pressurizing device, and after it is solidified, it acts as a reinforcing block. The process seals the cracks of the blocks, selects the appropriate glue injection point, and uses special equipment with a pressure of up to 30 kg to ensure that the whole pouring process is controllable and the crack filling rate is high, thereby ensuring smooth cutting of the blocks.

High-pressure infusion reinforcement is suitable for solving the problem of blockage damage caused by general permeability cracks. The process has the characteristics of machine automation, constant pressure and high pressure perfusion, low construction labor intensity, low cost and high efficiency.

5 vacuum perfusion

The vacuum infusion developed by Hunan Kesheng New Materials Co., Ltd. is different from the vacuum impregnation process in foreign countries, and does not require auxiliary equipment such as large tanks. The process uses a special sealing material to completely cover the block material, and then uses vacuum equipment to extract the air inside the bag, so that the pressure inside the bag includes the pressure at the crack of the block material to reach a vacuum state, and then the special low viscosity and high permeability glue is sucked into the bag. Inside, and then post-cure, it is a process of integrating the outer reinforcement of the block material.

Compared with high-pressure perfusion, it only solves the problem of transparent cracks. Vacuum infusion can solve all kinds of blocks with high or no cracks, such as permeability or impermeability, mesh and granular. The damage problem of Man, Magnolia, Lightning, Ou Dian, Sofitel, etc., the process technology has strong versatility. It can realize the integration of the inside and outside of the block. Because the glue is solidified in the vacuum bag, the construction site is odorless and reduces the VOC emissions. The most important thing is that the reinforcement effect is excellent, which greatly improves the sawing rate.

It is reported that the vacuum infusion technology of Hunan Kesheng New Material Co., Ltd. has been listed for only half a year, and has been fully cooperated in hundreds of stone enterprises such as China Global Group, Dongsheng Group, Xinpengfei Stone, Guangming Stone, Lifeng Stone and Xinsanfa Stone. The application, and foreign countries such as Turkey, Egypt, Indonesia, India and other countries have been widely used, and the excellent results have been unanimously recognized and praised by domestic and foreign customers.

6 Conclusion

The natural marble resources are not renewable, and the effective use of existing resources to improve the mining and processing rate is the common pursuit of the stone industry colleagues. As Hunan Kesheng New Materials advocated, “creating 100% new stone generation”, I believe that with the continuous advancement of stone block reinforcement technology, the engineering and technical personnel in the industry will work together to usher in such a “new stone generation”.

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