How to handle unqualified bending and compression stiffness of stone?

Bending stiffness and compressive stiffness are both technical indicators that demonstrate the destructive ability of natural stone materials. Failure to meet these two standards can limit the use of the product and affect its lifespan. If the product is used in pressure environments, it may also pose safety hazards. The main reason why the bending stiffness and compression stiffness do not meet the standard requirements is that the enterprise did not control the quality of raw materials when purchasing, received raw materials with many cracks, and did not take effective repair and reinforcement measures when processing the finished product.

Stone companies often encounter some cracked raw materials during the production process. How can we make up for these problems and produce qualified products? There are several main methods:

01. Reinforce the back of the stone slab with “back mesh” reinforcement

The “back mesh” reinforcement of the board is to use epoxy resin to bond the high-strength fiber protective mesh to the back of the board and dry it, so as to enhance the strength of the board. Usually, the “back mesh” reinforcement of stone panels is our first choice for panel reinforcement, as it is the most economical and cost-effective reinforcement method.

The solidification time is an important process parameter for reinforcing the back mesh plate, which depends on factors such as the quantity and output of the plate that needs to be reinforced with the back mesh, the operation method of the back mesh process, and whether to choose a drying furnace or the drying capacity of the drying furnace. If there are a large number of boards that need to be reinforced in the production line and the production requirements are high, mechanized back mesh reinforcement can be used, and the natural full curing method at room temperature or a drying furnace with flat curing heating can be selected.

If the production requirements are high, and even a vertical drying furnace can be chosen, a low viscosity epoxy resin ratio with a shorter solidification time should be selected. For some production lines with low production capacity, manual back mesh operation can be used, and the natural full curing method at room temperature can be used. Low-viscosity epoxy resin with a relatively slow solidification time can be selected to reduce the investment in production line equipment.

02. Surface Penetration Reinforcement of Plates

Stone is made by the aggregation of various minerals, and its microstructure has many voids, as well as many micro-cracks, and even cracks. Some cracks can even penetrate deep into the board, especially for marble.

However, some stones, after being reinforced with a “back mesh”, still cannot meet the strength requirements for grinding and polishing processing or the technical requirements corresponding to qualified finished boards.

So we will carry out surface infiltration reinforcement on these boards, which means that the highly permeable epoxy resin adhesive will penetrate into the interior of the stone through its own gaps and cracks. After drying, the stone will become a cohesive whole, thereby strengthening the stone and improving its strength.

03. High-pressure injection

High-pressure injection is a process of injecting special adhesive into the interior of the waste material using a pressure-boosting device, and reinforcing the waste material after it solidifies.

This process seals the cracks in the waste material, selects suitable glue injection points, and uses specialized equipment with a pressure of up to 30kg to ensure that the entire injection process is controllable and the crack-filling rate is high, thereby ensuring that the waste material can be reinforced and smoothly sawn.

High-pressure grouting reinforcement is suitable for solving the problem of waste material damage caused by general transparent cracks. It has the characteristics of machine automation and constant pressure grouting. This process has low labor intensity, and low cost, and can achieve high efficiency and efficiency.