Will concrete bond to day old concrete?

Author: Joelle Mann  |  Last update: Monday, September 22, 2025

Fact: Fresh wet concrete does not normally bond well to existing dry concrete. Do you remember elementary school where one of the subjects on which you were graded was “plays well with others”? Concrete would have gotten an F. There is nothing in basic portland cement that will act as a bonding agent.

Will new concrete stick to old concrete?

The cement in your concrete mix doesn't contain any bonding mix, meaning that when you attempt to lay fresh concrete over a layer of old concrete, the two will not stick. You'll end up with two separate layers of concrete that won't adhere to each other or create the desired effect.

Can I put another layer of concrete over 1 day old concrete?

You can pour concrete on top of an existing slab as long as it's still in reasonably good condition and structurally sound. This means the concrete should be free of cracks, buckling, and breaks. If you notice any small cracks or minor issues, it's in your best interest to repair them before you pour the new concrete.

How to make new concrete match old concrete?

  • Clean and roughen the existing concrete surface to be bonded to by the new concrete.
  • Either you make a slurry of cement, water and fine sand and paint the existing concrete or you use a commercial bonding agent and paint the surface to be bonded immediately prior to placing the new concrete.

Will Quikrete stick to old concrete?

QUIKRETE® Concrete Bonding Adhesive (No. 9902) permanently bonds new concrete, plaster, and stucco to existing concrete, plaster, and stucco. Eliminates the need for roughing the surface before the application. Exceeds the performance requirements of ASTM C 1059 Type I and II.

How to bond new concrete to old concrete

Can I use old concrete as fill for new concrete?

Old, unneeded concrete can be recycled and used to create recycled aggregate. In most cases, recycled aggregate will be used as a subbase material, but it can also be paired with virgin materials and reused as an aggregate in new concrete.

What is best to glue concrete to concrete?

Most epoxy glues for concrete come as two-part systems consisting of an epoxy resin and a hardener. When equal volumes of the resin and hardener are mixed, they react to produce a tough, rigid, high-strength bond. You can use epoxy resin for concrete to repair, fill, bond, and rebuild concrete surfaces.

Should you pin new concrete to old concrete?

Any time one is to attach new concrete to old concrete, it is likely for cracks to form and the sections will begin to separate. One way to help prevent that when attaching them is to use rebar to pin them together.

Can crushed concrete be used to make new concrete?

Yes, concrete can be crushed down, separated and reused.

What are the methods of joining old and new concrete?

Final Answer: The procedure to join old concrete and new concrete involves cleaning the surface, applying a bonding agent, pouring new concrete, and finishing it. Common materials for filling joints include silicone sealant and polyurethane sealant.

How to put new concrete on top of old concrete?

Apply the bonding adhesive or interlay layer: Spray the existing concrete with water to dampen the surface. For a bonded overlay, apply a bonding agent. For an unbonded overlay, add your interlay layer so the top surface is level. Pour the concrete and apply the curing compound: Pour your concrete.

What happens if you put too much cement in concrete mix?

To summarize, adding too much cement to a concrete mix can result in decreased workability, poor bonding between the cement and aggregates, and the formation of honeycombing. These consequences can have a detrimental impact on the strength and durability of the final concrete product.

How long to wait before pouring the second layer of concrete?

In order for the first layer of concrete to fully cure, you need to wait one month.

What epoxy is used to bond concrete to concrete?

REZI-WELD GEL PASTE is a two-component, moisture-insensitive construction epoxy, which can be troweled, brushed, injected, or pumped. REZI-WELD GEL PASTE is used to bond hardened concrete to fresh or hardened concrete. It can also be used to bond metals and other materials to hardened concrete.

Can you overlay old concrete?

Fortunately, it is possible to place stamped concrete over existing concrete. Stamped concrete overlays are durable options for upgrading, repairing, and enhancing existing concrete.

Do I need an expansion joint between old and new concrete?

Guidance from the American Concrete Institute (ACI PRC-224.3-95: Joints in Concrete Construction) says that “the expansion of concrete slabs on grade is generally less than the initial shrinkage, and provision for expansion is seldom required.” Regarding the regular use of expansion joints, the guide also states “ ...

How do you make new concrete adhere to old concrete?

Chemical bonding involves using a liquid bonding agent to stick new concrete to the surface of old concrete. Apply the bonding agent to existing concrete and let it dry before applying the repair material.

Will crushed concrete harden?

Although crushed concrete will compact and harden over time, it may not be as strong as the original concrete structure or stone. Some studies show that the strength of recycled concrete is between 90% and 70% compared to freshly poured concrete.

Can you grind up concrete and reuse it?

It's recycling! Recycling crushed concrete to be reused helps reduce landfill crowding AND saves more resources from being used to create new concrete.

Will wet concrete stick to old concrete?

Fact: Fresh wet concrete does not normally bond well to existing dry concrete. Do you remember elementary school where one of the subjects on which you were graded was “plays well with others”? Concrete would have gotten an F. There is nothing in basic portland cement that will act as a bonding agent.

Can I put Quikrete over existing concrete?

QUIKRETE® Re-Cap® Concrete Resurfacer is designed to provide a new, durable, and wear-resistant surface over worn or scaled concrete. Use For: Sidewalks. Pool Decks.

Should you hose down new concrete?

Spray: To maintain the proper moisture levels, concrete should be sprayed with water frequently. This is known as moist-curing. Most specialists recommend watering the slab 5 to 10 times per day for the first seven days. Moist-cured concrete can be up to 50% stronger than dry-cured concrete.

What can I use to stick concrete to concrete?

Bonding Agent® is a multipurpose product formulated for use as a bonding agent when pouring new concrete over existing and also as an admixture for all types of cementitious structural repairs and resurfacing projects.

What is the strongest concrete bond?

MPC (Magnesium-Phosphate-Cement) is a unique form of concrete developed by Phoscrete and others and researched and reported by the US Army Corps of Engineers. The magnesium phosphate cement binder forms a much stronger bond to concrete (and to itself) than traditional OPC (ordinary Portland Cement) concretes.

Does Gorilla glue work on concrete to concrete?

Gorilla Max Strength Clear Construction Adhesive will work on concrete, however the glue is not recommended for rubber. If we can be of any further assistance, please contact our Support Team at 800-966-3458 or visit our Contact Us page at www.gorilltough.com/contact.

Previous article
Do microwave sensors interfere with WiFi?
Next article
Can you install a dryer by yourself?