Can I cut horizontally with my excavator rocksaw?

With diamond cutting, the water that you use to cool the blade, also helps to lubricate the blade.

when cutting in rock or concrete, the water is contained by the cut, however, when cutting in loose material such as the base under asphalt or concrete surfaces, the water drains away. This base material can be highly abrasive, and there is very little water providing the needed lubrication and cooling.

The result is rapid undercutting of the steel centre of the blade.

This of particular concern for larger blades as the cost of the steel centre is high, and wear reduces the possibilities for retipping. Which of course means that you need to replace the entire blade.

You can tell when you have cut through into the base material. There will be less water coming out of the cut, and colour of the water is likely to change.

The remedy is to take notice of the change in the water and to reduce the depth of the cut until you are out of the base material.