The MK Diamond 150227 MK-615W 12 in. x .375 x 1 in. is a wet-cutting segmented rim diamond blade built for one job in particular: cutting straight down through an asphalt overlay and into the concrete slab underneath it. That is the situation road crews, utility contractors and municipal maintenance departments run into constantly on streets and lots that have been resurfaced over an original concrete base, and it is the situation where a general-purpose blade tends to disappoint.
Built for asphalt over concrete - not for plain asphalt
This distinction matters more than the spec sheet suggests. MK Diamond publishes an application chart for its wet-cutting asphalt line, and on that chart the MK-615W is rated its best option for asphalt over concrete while being listed as not recommended for straight asphalt. The reason is bond hardness. Soft, abrasive asphalt wants a hard bond that holds its diamonds; hard, dense concrete wants a softer bond that keeps exposing fresh ones. An overlay cut demands both in the same pass, and the MK-615W is formulated for that compromise. Buying the right blade for the layer you are actually cutting is the cheapest blade-life decision available.
Use cases
- Full-depth cuts through an asphalt overlay and into the concrete base underneath, without swapping blades at the interface
- Squaring up patch boundaries and utility-cut outlines on overlaid roads, parking lots and aprons
- Trenching and pavement removal layouts where the slab under the blacktop has to be cut cleanly rather than broken out
- Municipal and DOT maintenance work on streets that have been resurfaced one or more times
Choosing the right diameter and kerf
The 12 in. diameter sets how deep you can reach; the .375 in. kerf sets how wide the slot comes out and how hard the saw has to work. This blade carries a wide kerf that opens a substantially broader slot in a single pass. A wide kerf is not about cutting faster - it is about the width of the slot you end up with. Crews reach for it when the opening itself has to be wide enough to take a sealant reservoir, backer rod, conduit or a patch key, and it asks for more horsepower and more water than a thin blade doing the same depth.
At 12 in. this is a mid-range diameter and the most widely stocked size on small and mid-size walk-behind saws. Twelve inches is the workhorse diameter for utility cuts, patch outlines and control joints on lighter machines. It reaches through most residential and light-commercial overlay sections while staying well inside the power band of a smaller saw, which is why it is usually the first blade on the trailer.
Specifications
- Model: MK Diamond MK-615W, Premium Grade for Asphalt Over Concrete
- Part number: 150227
- Diameter: 12 in. (305 mm)
- Width (kerf): .375 in.
- Arbor: 1 in.
- Segment height: 10 mm
- Rim type: Segmented, laser welded
- Cutting method: Wet only
- Saw horsepower range: 8 - 20 hp
Getting the most life out of the blade
Four habits account for most of the difference between a blade that lasts a season and one that is scrap by Thursday. Keep the water on, every cut. Step-cut rather than forcing full depth in one pass, which spikes the amperage the saw draws and glazes the rim. Check the directional arrow before mounting - a blade spinning backwards still cuts, briefly, while it chews through its own diamonds. And on a walk-behind, use the drive pin hole as well as the arbor so the blade is not free to wobble in the cut. If you need to change direction, lift the blade clear and shut the machine down first rather than twisting it in the kerf.
Frequently asked questions
Is the MK-615W the right blade for plain asphalt?
No. MK Diamond rates the MK-615W as its best choice for asphalt over concrete and does not recommend it for straight asphalt or for asphalt with soft aggregate. For those materials MK points to its asphalt-specific lines instead. Matching the bond to the material is the single biggest factor in how long a blade lasts.
Can this blade be run dry?
No. The MK-615W is a wet-cutting blade and has to be run with water. Running a wet blade dry is one of the most common ways crews ruin a blade - friction builds heat faster than the steel core can shed it, and the damage is usually permanent within a single cut.
What size saw does it fit?
The MK-615W family is built for saws in the 8 to 20 horsepower range and uses a 1 in. arbor. This 12 in. blade carries a .375 in. kerf and a 10 mm segment height.
Why cut asphalt over concrete with one blade instead of two?
An overlay section is two materials with opposite demands - soft, abrasive blacktop on top of hard, dense concrete. A blade bonded for one tends to fail on the other. The MK-615W is bonded to handle the transition, so a full-depth cut can be made in one setup rather than stopping to change blades partway down.
How deep should the blade be run in one pass?
Less than you might expect. Burying a blade to the flange raises the load on the saw, overheats the rim and shortens blade life. Step-cutting in several shallower passes is the standard recommendation, and experienced operators generally stay well short of using half the blade diameter on any single pass.
Discount Cleaning Products is an authorized MK Diamond dealer, and we support what we sell from here in the United States. MK Diamond has been building cutting, coring and polishing equipment for the masonry and concrete trades for generations, and its blades are manufactured to published, verifiable specifications - which is why the dimensions above come straight from the manufacturer rather than from a catalog listing. If you are not certain which diameter or kerf suits your saw and your pavement section, get in touch before you order.
