You can pour slabs in sections, you just need to pin them together with rebar so that they stay in alignment. This is how concrete road surfaces are done.
A two-stage pour foundation is essentially just that; where there are two different types of concrete poured into the foundations and different stages. This type of foundation solution might be used where we have variable soils with a clay content, which means foundations span between different bearing strata.
A Monolithic Slab Foundation
The entire surface of the building site has to be tamped down and fully prepared, all at once. This is because a monolithic foundation is all one piece; the concrete footing and floor are poured together.
Yes, you can.
Since cement lacks any natural bonding agents, newly-poured concrete won't naturally bond to the existing slab. You'll need to either use a bonding agent to adhere the two layers together or use an unbonded overlay method. Condition-affected life span: Properly installed concrete can last for over 50 years.
When you're joining two concrete slabs, connect the two with rebar to keep them at the same height. Drill the holes as deep as you can (the entire length of the bit) so the rebar fits snugly into the holes. Insert chunks of rebar and tie them into the grid.
An expansion joint is a material placed in the cracks (or joints) between concrete slabs to protect the slabs from cracking when they contract and expand as the temperature changes. This material acts as a shock absorber, absorbing the stress from the slab's movement.
Because concrete is a very porous material, it will absorb any moisture that it contacts. This can cause pooling. Without crushed stone, pooling water will settle under it and erode your slab. Adding a layer of crushed stone will add proper drainage, as well as create a barrier between your slab and the ground.
Foundation Definition: The footing is generally supporting columns and may be round, square, or rectangular at a plan and in section. They may be of the slab — stepped or sloping type. This stepped footing results at a better distribution of load than a slab footing.
Concrete that is not moist-cured at all dries too rapidly, and reaches less than half its potential design strength. It will also have a greater number of shrinkage cracks.
Working With Ready-Mix Concrete
And, if you mix it yourself, it's the cheapest way to make your slab. For most do-it-yourselfers, the best material for building a concrete slab is a ready-mix, crack-resistant concrete product. The wet mix is poured into a prepared wood form, then left to cure.
Rebar is not necessary for every concrete project. The general rule of thumb is that if you are pouring concrete that is more than 5 inches in depth, you are probably going to want to add in some rebar to help reinforce the entire structure.
Fresh concrete shall not be placed against in situ concrete that has been in position for more than 30 minutes unless a construction joint is formed.....
Does concrete stick to concrete? If you pour a new layer over concrete right on top of the old one, you won't get proper adhesion. You must properly prepare your concrete slab and then apply a chemical bonding agent on top of it so your new concrete adheres properly.
Yes, you can pour fresh concrete over existing concrete. As long as your concrete is in mint condition, this task is doable. If you decide to pour a new mixture over an old slab, be sure it is at least 2 inches thick.
If the weight of the concrete deforms the dirt base in any way, the entire concrete structure will be flawed. All of that is not to say that it is impossible to pour concrete over dirt. You can absolutely do it successfully, but you need to follow a specific process.
As a general rule, stay away from using sand as a subbase. You're better off using gravel; your concrete will last longer and have less of a chance of cracking over time.
Most concrete contractors want a mix of coarse and fine aggregate to create a compactable base that is going to be safe for settlement and drainage. Crusher run (a mix of crushed stone and stone dust) and #57 coarse aggregate are two of the best base materials for concrete slabs.
Larger, deeper slabs that are designed to bear some weight of a structure will require steel rebar mesh to reinforce the slab and spread the load.
Expansion joints are full-depth gaps between individual poured-concrete slabs and are sometimes called isolation joints. The gaps allow the slabs to move with normal expansion, contraction or settling that occurs due to temperature changes or moisture conditions.
Cutting freshly poured concrete too late can lead to unwanted cracks in the concrete, rendering the joints ineffective. Too early and the concrete will not have cured enough to support the saw and operator.
You can put new concrete over old concrete. However, unresolved issues with your old concrete, such as cracks or frost heaves, will carry over to your new concrete if not taken care of. In addition, you must pour it at least 2 inches thick.
Contraction/control joints are placed in concrete slabs to control random cracking. A fresh concrete mixture is a fluid, plastic mass that can be molded into virtually any shape, but as the material hardens there is a reduction in volume or shrinkage.
In case of one-way slab, if we increase the beams width to depth ratio, and increase the percentage of steel, perpendicular to the direction of bending, then one-way slab will be more economical and will be stronger than two way slab.