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When the slab is loaded and force applied to it,
the top of the slab directly under the load will be put in compression.
However at the bottom of the slab. the concrete will pull itself in tension.
Put the ends of your fingers together than flex your wrist up.
You will feel the pressure at the top of your fingertips and
you will see a gap open at the bottom.
That is what is happening in a slab.
Concrete is strong in compression, poor in tension.
Rebar, or steel, is the opposite.
By combining the two, you develop a product that is superior
and complimentary to the strengths and weaknesses of the individual materials.
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What is two way slab?
Two-way slabs are rectangular reinforced-concrete slabs that are supported on all sides. The reinforcement is placed perpendicular to the sides.
What anchor should you use with a concrete block wall?
bent and tied metal rebar for the slab-to-wall connection at all filled cells bent metal straps embedded into the lintel to connect roof to wall
What temperature does concrete need to be to harden?
all things that need to dry are based on 72 degrees concrete needs 30 days to fully cure.
What is bleeding in concrete?
Bleeding in concrete is sometimes referred as water gain. It is a particular form of segregation, in which some of the water from the concrete comes out to the surface of the concrete, being of the lowest specific gravity among all the ingredients of concrete. Bleeding is predominantly observed in a highly wet mix, badly proportioned and insufficiently mixed concrete. In thin members like roof slab or road slabs and when concrete is placed in sunny weather show excessive bleeding.Due to bleeding, water comes up and accumulates at the surface. Sometimes, along with this water, certain quantity of cement also comes to the surface. When the surface is worked up with the trowel, the aggregate goes down and the cement and water come up to the top surface. This formation of cement paste at the surface is known as "Laitance". In such a case, the top surface of slabs and pavements will not have good wearing quality. This laitance formed on roads produces dust in summer and mud in rainy season.
Can you needed to cure a blinding concrete?
All concrete need curing, since blinding is not structural concrete and treated as leveling course only, duration of curing may reduced. There is no specific period mentioned in relevant standard for curing of blinding.
What is two way slab?
Two-way slabs are rectangular reinforced-concrete slabs that are supported on all sides. The reinforcement is placed perpendicular to the sides.
I am building a 2'6 wall for a garden that will be filled with dirt should i re-bar the wall?
Yes, if you are constructing this wall with concrete block you will need #5 rebar dowels stubbed out of the foundation at 32" on center. You will also need one #5 rebar running continues in the top course and fill all cells with dowels and top course with either structural grout or concrete.
What is the meaning of steel re bar?
Rebar is an informal term for steel "reinforcing bar". These are steel bars that are placed within the structure before the wet concrete is placed. Steel reinforcement is necessary for almost all structural concrete because concrete has virtually no tensile or shear strength. The rebar provides almost all of the resistance to tension and shear within the structure.
Do all concrete slabs need rebars?
When the slab is loaded and force applied to it, the top of the slab directly under the load will be put in compression. However at the bottom of the slab. the concrete will pull itself in tension. Put the ends of your fingers together than flex your wrist up. You will feel the pressure at the top of your fingertips and you will see a gap open at the bottom. That is what is happening in a slab. Concrete is strong in compression, poor in tension. Rebar, or steel, is the opposite. By combining the two, you develop a product that is superior and complimentary to the strengths and weaknesses of the individual materials.
How do you paint a rusty concrete?
Rusty concrete is there such a thing? If the concrete is rusty because it was stained by steel laying on it, that will be easy. Clean the concrete with some muratic acid (follow the instructions on the jug), rinse it, then paint it with concrete paint. Your local hardware store can provide different colors and options depending on the product line(s) they carry. If your concrete is rusty because the rebar is rusting and the rust is bleeding through, you have a problem. You need to remove all of the spalling, loose, and unstable material from around the rebar and then patch the spot. You might be able to prep the area with a pressure washer or you might need a cold chisel. Rusting steel rebar destroys concrete because it swells and splits the concrete. The surface needs to be sound before you paint. Painting is easy, surface prep always takes the most time.
How much rebar do you need for 2 cubic yards of cement?
The amount of rebar depends on the thickness of what you are making. All three dimensions.
Why are Jewish graves covered with slabs of concrete in addition to the tombstone?
Although not all Jewish graves are covered by concrete slabs, Judaism has very strict rules regarding grave desecration so at the minimum, a tombstone must be erected. One law is that Jews are not supposed to walk on graves so many Jewish cemeteries use these slabs, or sometimes concrete curbs to clearly delineate the location of the grave.
How much rebar do you need for 10 x 15 slab?
If your peice of concrete does not have beams I consider that flatwork. So in flatwork with 3/8 rebar (#3) on 16" centers, for the 15 foot side you will have 8 pieces x 15' long. On the 10' side you will need 12 pieces x 10'. (6 bars cut in half) In all you will need 14 #3 x 20'
What is the difference beteween Structural slab vs slab on grade?
Structural slabs are typically elevated concrete slabs - 2nd floor, 3rd floor, roof, etc. These slabs will contain steel reinforcing (rebar) or post-tensioning (tendons). The steel provides strength to support loads, ductility to prevent sudden failure, control of movements/cracks (due to temperature changes (thermal expansion/contraction) and shrinkage stresses (which occur as concrete cures)). Slabs on grade are concrete slabs cast on the ground, usually over an aggregate base course. They may or may not contain rebar or tendons (sometimes they contain welded wire fabric) - these are all for movement/crack control, and may also be used where soil problems are anticipated (expansive soils). There is also something called a structural slab on grade (or structural slab over backfill). A common place to see these is on exterior slabs that occur over backfills adjacent to the basement of a building. This artificially compacted backfill will often settle, especially if exposed to water (even if properly compacted). If it is critical to limit settlement of a slab that is over backfill, the slab is usually designed and constructed as a structural concrete slab which spans across the backfill soil (and does not depend on support from the backfill soil). The slab will usually span from the basement wall (which it bears on or is connected to), over the backfill soil, and bear on native soil.
What should you do about rebar that's rusting?
Until all the rebar is gone. Rebar is just low grade steel with next to nothing in it to prevent rust. After a surface coat of rust gets on it (2-3 days) it will slow the process but it will never stop. Rebar is normally set inside concrete which also slows down the rusting but if you break open any concrete slab with rebar in it you will see it has rusted. Better still, avoid the problem in the first place. If you don't want to see rust, don't use steel. use composite (FRP) rebar. this is manufactured from glass-fibre based composites and is used where steel can not or should not be used.
What is mivan construction?
Mivan Technology involves columnless , beamless construction but usually all walls & slabs are of 150mm concrete and slabs as a whole. Pre-planning is required to leave openings for doors,window & services shafts in shuttering itself.
Paving slabs used are all 1 foot square Customers tell Joe the dimensions of the pond and he has to work out how many paving slabs they need How many slabs are needed to surround 115 ft by 115 by ft?
Joe needs 460 paving slabs to surrond the pond.
