Welded Wire Mesh & Fiber Mesh

Jim Anton

Besides the cost of Wire Mesh and installation of the wire mesh. Are there any advantage of using both Welded wire mesh and fiber mixed in with the concrete using both materials together?. I am replacing existing concrete driveway and putting in proper drainage ect. I do not want to do this again.

House Engineer

If you ask 10 people this question, you will probably get 10 answers. Here is one of them. You are asking a controversial question because of the intensive marketing efforts for both materials.

The mesh, which is now called welded wire reinforcement (WWR), and the polypropylene fibers are secondary issues in the creation of a strong, quality driveway. The steel area of the mesh is less than what is needed to provide much strength or crack control; and the mesh is usually too improperly placed in the slab to be effective in strength or crack control. The polypropylene fibers do not add significant strength, but do reduce cracks from plastic drying shrinkage.

The best things to do are: have a well compacted sub-grade, use a thick, well compacted rock sub-base, use a good quality concrete mix, with a low water/cement ratio (by adding superplasticizers, water reducers, etc). Add a corrosion inhibitor to the mix if you live in a northern climate where road salts are used, Use properly spaced and installed construction joints and control joints, and cure the slab properly. Provide good drainage off the slab and avoid water flow under the slab. Don't over-trowel the mix. Properly cure the slab with a sealer and a wet cover.

If you do everything mentioned in paragraph number 2, what you do in paragraph number one is not as critical.

House Engineer

And if you live in a cold climate, add air entrainment to the concrete mix to add to the freeze/thaw durability of the concrete.

concretemasonry

Use 4000 psi minimum and 5% air with 3" maximum slump if you are in cold climate. Some intermediate areas have more durability problems than the far north because of the number of annual freeze-that cycles and type of deicers used and pretreatment with vegetable based materials makes snow removal much easier. The pretreatment is not practical in the warmer cold areas because it washes off if there is rain or melting.


I had a driveway put in in northern MI. - 4" thick on a well compacted base with 4500 psi air entrained concrete with fiber mesh. It also had WWR supported to make it easier to pull up as placement proceeded. The contractor marked the forms to avoid the mesh from spanning the palnned joints. Concrete poured in the am and joints sawed that afternoon. The strange thing was that the city would not allow mesh or reinforcement on a portion on the boulevard (city property) since the frost level was about 4' and depth to rock was also about 4', so there were many maintenance situations on the boulevards.

The cost of the fiber mesh and WWR was minimal in the big picture. I saw the driveway last year and it looked as good as new except for a few very small widely spaced small minor pop-outs (1 that was less than 1/4" per 4 square feet) of the local aggregate, but the state approved aggregate was in short supply at the time. Still, it was good (almost perfect) after 10 years.

Dick

davido

Yeah I agree, that's what I would do.
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