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Your Position: Home - Construction & Real Estate - Fibre Mesh v Steel Reinforcement in Slabs | Eng-Tips

Fibre Mesh v Steel Reinforcement in Slabs | Eng-Tips

Fibre Mesh v Steel Reinforcement in Slabs | Eng-Tips

The primary methods to prevent early age cracking are concrete quality, finishing, and curing. The primary method to control longer term cracking is subgrade preparation. For heavily loaded slabs, increased thickness and discrete reinforcement are the best controls.

The use of fibers is limited to non-structural purposes, with few exceptions. This is primarily because the distribution and orientation of fibers is not assured. Distributed fibers help reduce crack width by encouraging development of multiple, small cracks, or in some cases, helping to improve the properties of concrete which reduce cracking. Once cracks start to grow, they are controlled by the modulus and area of fibers and reinforcement crossing the cracks. The modulus of plastic fibers is far below that of steel (- ksi for plastic v 29,000 ksi for steel.) The use of discrete (conventional) reinforcement assures that crack width is controlled once they start to grow. In slabs, this is usually relatively less important, but we have been seeing quite a few large companies move back to conventionally reinforced slabs after finding that fiber and unreinforced slabs did not perform well enough. Some slabs where poor performance was seen were well prepared and cracking was the result of loading and/or restraint, and the lack of reinforcement allowed wider crack propagation and/or vertical faulting.

In reinforcing an indoor slab, small, closely-spaced bar or wire will generally control cracks better than larger, widely-spaced reinforcement. Having reinforcement closer to a surface will restrain cracks on that surface better.

State of the practice for design of slabs is provided in ACI 360:

Construction practices are covered by ACI Committee 302:
This is due for an update, and the committee is now doing that. hokie66....
TXstructural....

EXACTLY!!

Fiber is an enhancement to the concrete mix....it is not reinforcement
It increases both the flexural (good) and compressive strength (not so much) (steel fiber only...polypropylene is worthless...as noted by hokie66)

I spent about 10 years on the ACI Committee for fiber concrete. It was a constant effort trying to keep the BS out....fiber provides some help, but it does not replace reinforcement and its crack limiting capabilities are limited as well.

The most significant effect that I've seen with fibers (steel fibers, again), is a reasonable increase in the modulus of rupture. Thanks Folks,

Seems to be a hotly debated topic.

The application I am considering is for a sand & aggregate storage shed (quarry). The floor (on grade) will be subject to loads from plant and materials. My approach is to design a floor slab which is suitable for use and to simplify its construction as much as possible.

Therefore, I am considering a deep slab (200mm / 8") with 1 no. layer A252 mesh (bottom) with fibre mesh reinforcement within the concrete mix. This will allow me to increase control joint spacings and allow for larger pours. The slab will be laid on graded hardcore well compacted in 9" layers. The slab does not need to be a super flat floor nor is the application the interiro of a 5* hotel, with a tiled finish, therefore, it does not need to be over-designed in terms of crack control. Primary objective is functionality & durability.

The viewpoints above are all valid and informative, many thanks.



murdydrum
chartered engineer
Depending on the soil type, an 8" slab for moderate loading should be OK... you can check the design. A good high strength concrete, low slump, sawcut into proper sizes at the right time and curing should all be used. I'd probably use regular reinforcing steel properly chaired and not WWM/WWF. I'd skip the fibres completely, steel and/or polypropylene. The former should be used if there is heavy equipment moving on the slab. In addition to the rust noted by MM, they are really difficult to work with.

Dik I stick by my recommendation to use steel fibers, based on the desire to minimize the need for crack control joints in an industrial slab where they're storing sand and aggregate. The slab will be subject to heavy abuse, both from the product itself, and it's likely that front end loaders will be used... they'll tear up the joints! The use of steel fibers allows larger slab areas to be poured without joints.

For normal industrial floors, I'm all for reinforcing bars (mesh is a joke), but you generally cannot stretch the joint spacing with reinforcing, and it does nothing for durability and abrasion resistance. Steel reinforcing is normally placed in the upper 1/3 of the slab to control cracking, rather than being used for bending strength, so it generally doesn't help you there. Murdy stated his "primary objective is functionality and durability". Steel fibers give you that... improved bending strength, crack control, fewer joints, abrasion resistance, lower maintenance costs, etc., etc..

Msquared... you seem real hung up on the fuzzy/rusty floor thing. Have you ever seen a properly constructed steel fiber floor? The fibers to not stick out. Sure you'll get a little surface rust, but who cares? This is an industrial building that somebody is dumping rock and sand on, and running over with heavy equipment.

Another suggestion to increase strength and limit joints, Is the post-tension the slab. Post-tensioning can also be used to reduce the thickness of the slab. While I agree with spats's basic premise, I do not agree that the use of fiber will allow no joints. It will allow different spacing of the joints (distance between joints can be a bit more), but it will not preclude the use of joints.

An hokie66 noted, the toughness of the slab will be increased by the use of fibers.

As dik alluded, don't let the fiber addition substitute for sound concrete mix design and placement practices.

Do Concrete Slabs Really Need Welded Wire Mesh? - TWP Inc.

Welded wire mesh was once the go-to material for forming concrete slabs and reinforcements, but some builders have recently opted for the fiber variety. Though developers may cut costs by opting for synthetic mesh, there are a few things to consider before making the switch.

Heyou contains other products and information you need, so please check it out.

Read on to learn about the potential drawbacks of fiber cloth and why traditional welded steel mesh may be the best choice.

What to Consider Before Using Fiber Mesh

One of the main reasons mesh is used for concrete slabs is to prevent surface cracking. Though fiber cuts down on the number of breaks, it doesn't eliminate them entirely. Not only that, but when cracks appear, fiber mesh often lacks the strength to stop them from spreading.

So, while synthetic mesh may be more affordable upfront, builders could end up paying more for repairs down the road. Homebuyers and commercial real estate investors are often on the lookout for flaws, and cracks on a new build can stick out like a sore thumb.

Another thing to consider is that fiber mesh doesn't do as good a job preventing differential settlement. Seeing as a level foundation is vital, and fixing it isn't always a simple process, this is a major concern.

Welded Wire Mesh for Concrete Reinforcing

Created by heating intersecting metal wires with an electric current, welded wire mesh boasts impressive rigidity. It's also resistant to abrasion, rust, corrosion, and extreme temperatures.

These characteristics make welded stainless steel cloth ideal for concrete reinforcing, a process that relies on exceptional strength and inflexibility. The durable alloy also helps ensure foundational evenness.

The company is the world’s best Slab Mesh Factory supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Do Concrete Slabs Really Need Welded Wire Mesh?

There's no one-size-fits-all way to construct houses and buildings. The choice of materials often depends on various factors, like availability, budgeting, and whether substantial settling is common in the area.

All that said, welded reinforcement concrete mesh remains the gold standard for construction. The heavy-duty product is incredibly sturdy, resilient, long-lasting, and versatile.

Minor cracks and slight foundational settling are often to be expected, even with new builds. Still, too many imperfections can signify poor workmanship and lead to prospective buyers feeling dubious about the structural integrity.

Ensuring Crack-Free Concrete

Choosing welded metal mesh over fiber is the best defense against cracks in concrete slabs. However, as with all structural projects, the material can't do its job if it's not installed correctly. Proper installation ensures the maximum level of strength is applied, which keeps breaks at a minimum.

For more insight into this topic, see our Guide to Wire Mesh for Construction & Building.

Metal Wire Mesh Products for Construction & Building

As one of the top wire mesh suppliers in the world, TWP Inc. is a premier resource for critical construction and building materials. When you shop our inventory, you'll find T-304 and T-316 welded stainless steel mesh with various gauges, opening sizes, and mesh counts.

We also offer expert in-house services, including laser cutting, disc stamping and sizing, roll slitting, and ultrasonic cleaning. If you don't see the specification you're looking for, we're happy to accommodate custom orders. Request a free quote to get started!

For more Rebar Welded Wire Meshinformation, please contact us. We will provide professional answers.

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