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Things Need To Know When Grinding Hard Concrete

When discussing how hard concrete is to grind, many people confuse hardness and strength. Strength is measured in MPa and is a measure of compressive strength. It is true that high compressive strength can be harder, but not always. This is because the aggregate and sand in high MPa concrete is likely to be the same in low MPa concrete. The difference is in the amount of cement and water.

When we talk about hardness to grind, it really is all about the kind of dust that is produced during the process. Hard concrete tends to produce ultra-fine dust. This dust is very un-abrasive and it does not wear the matrix of the diamond segment sufficiently. The result is that the diamond grit soon becomes hardly exposed so it grinds even finer and powdery dust. The segments stop grinding and the segments will get hot and glaze over.

Grinding hard concrete means that the dust is soft and un-abrasive so the metal matrix that the segment is made of needs to be soft bond and easily eroded to expose the diamonds. Often a coarser grit can be beneficial because it may produce coarser dust to help erode the matrix.

In addition, reducing the contact area with fewer segments makes a difference. This also has the effect of increasing the weight per square inch on the surface so that the diamond grit will occasionally crack a little bit off the peak to create a fresh sharp peak and start grinding again. Diamond grit will gradually round over if it does not crack off a little bit from time to time. Rounded grit won't grind too well. This is why you will find that adding extra weight or ensuring all the weight of the machine possible is on the head. It helps to keep the diamonds working.

Some tips of grinding hard concrete:

● Use diamond tooling with a soft bond or fewer segments for hard concrete and increase the weight on the diamond tooling. Using coarser grit diamond may increase the dust size and keep the diamond tooling working.

● One of the most important things is that do not use diamond tooling for hard concrete on soft concrete; they will almost certainly wear out incredibly fast.

● If you turn down the vacuum so there is plenty of dust under the machine, this will help the diamonds to expose. Careful addition of sand may also help. Don't overdo sand, it could cause premature wear.

● Remember to inspect your concrete floor diamond tooling. If there is hardly any diamond exposed out of the matrix or the tooling is getting hot, stop and change to a softer bond or fewer segments.

● Wetting the concrete before grinding helps to expose the diamonds a little more. Try to scratch open the surface first, then apply water and give it a little time to soak in. This process makes the dust a little heavier which cuts the matrix more to expose more diamonds.

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