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Avoid Surface Defects on Exterior Slabs | For Construction ...

Surface sealing is more likely to occur when using steel trowels or fresnos to finish air-entrained concrete. A fresno is a long-handled trowel with a 5-in.-wide and 24- …

EZ Trowel™ Concentrate - Specco

EZ Trowel Concentrate forms a lubricating gelled surface film which reduces plastic shrinkage cracking and wind crusting and allows the surface to remain plastic for extended finishing time. EZ Trowel Concentrate can be used effectively on both air-entrained and non-air entrained concrete flatwork, and concrete mixes containing silica fume, fly ...

Floated and trowelled finishes - Concrete

Power trowelling of air-entrained concretes is not recommended due to the risk of surface delamination. Also, trowelling before the bleed water has evaporated can lead to a risk of delamination. It is also difficult to get the power float and trowel up to a fixed edge/wall/cladding or a formed joint, therefore some hand finishing may be ...

Air tests for non-air-entrained concrete

Note that it is recommended to require air content testing for non-air-entrained concrete used for floors and slabs. ACI 301-20 "Specifications for Concrete Construction" require the total air content of hard-troweled interior concrete floors to not exceed 3 percent. According to ACI 302.1R-15 "Guide to Concrete Floor and Slab ...

What is air entrained concrete? - findanyanswer.com

to hard-trowel air-entrained con- crete.The risks associated with this requirement include: ACI 302.1R-96, "Guide for Concrete Floor and Slab Construction," states that entrained air is not recommended for concrete to be given a smooth, dense, hard-troweled finish.

Steel Trowel Finishing and Air Entrained Concrete

entrained concrete). A core sample of air-entrained concrete with a machine trowel finish exhibited the fol-lowing: Percentage of air in the top 4mm of slab surface: 0% Depth at which the air content is incorrect: up to 25 mm Depth at which the air bubble spacing is incorrect: up to 85 mm Considerations: In saturated freeze-thaw conditions, air ...

Avoiding Surface Defects Finishing Interior Concrete ...

ACI 302.1R-04 Guide for Concrete Floor and Slab Construction recommends not specifying or using air-entraining agents for concrete to be …

What is the difference between air entrained and non air ...

The risks associated with this requirement include: ACI 302.1R-96, "Guide for Concrete Floor and Slab Construction," states that entrained air is not recommended for concrete to be given a smooth, dense, hard-troweled finish.

Finishing Air-Entrained Concrete

The air voids again provide relief sites for the buildup of salt concentrations and the pressures that result due to concentration gradients. Other uses of air-entrained concrete include sulfate resistance, resistance to alkali-silica reactivity, and improved …

STATE UNIVERSITY CONSTRUCTION FUND

Air entrainment shall not be used on interior concrete work unless the concrete is to be exposed to freeze/thaw cycles during the construction phase. Do not trowel finish concrete that is air entrained. b. Use the lowest water slump concrete practical for the application. It will reduce shrinkage and provide a more durable concrete surface.

What Is Concrete Delamination & How Can I Prevent It ...

Avoid using dry shakes on air-entrained concrete. Promote even setting throughout the slab by using accelerated or heated concrete. If possible, never place concrete on top of a vapor retarder. If an interior slab requires a trowel finish, don't use air-entrained concrete.

CIP 1 00 - CONCRETE IN PRACTICE

must be air-entrained. Severe exposures require air contents of 6 to 7 percent in freshly mixed concrete made with 3/ 4-inch [19 mm] or 1-inch [25-mm] aggregate. In moderate exposures, where deicing salts will not be used, 4 to 6 percent air will be sufficient. Air-entrained concrete of moderate slump (up to 5 inches [125 mm]) and adequate ...

Finishing air entrained concrete - Structural engineering ...

For a new parking garage floor with specified 5% to 8% air entrained concrete, and a urethane waterproofing membrane 60 mils thick, a wood float finsh is too rough. The concrete requires a steel trowel finish according to the membrane manufacturers. CSA Standard S413 says that a "single pass" of the steel trowl is ok on the air entrained concrete.

Air Entrained Concrete and Trowel Finishing - Structural ...

Excerpt from A23.1 "7.5.4.3.2 Exterior or air-entrained concrete One or more passes of a magnesium float or concrete broom shall be made at suitable time intervals to obtain a level finish free of ridges. A steel trowel finish shall not be applied to air-entrained concrete."

8 Types of Concrete Finishes [PDF] - The Constructor

Types of Concrete Finishes 1. Troweled Finish . Trowel finish is the most common and popular finish of concrete used for major types of applications. After the concrete is laid in the formwork and leveled, the trowel is used to smooth and fine-level the surface of concrete.

Modifications to ACI 301 - American Concrete Institute

ACI 301-10 continues to require that the concrete be air-entrained as the default requirement. Using air- entrained concrete for hard-troweled concrete floors increases the chances of delamination. The optional requirement checklist advises the A/E to specify non-air-entrained concrete when the floor will be hard-troweled. As-cast concrete finishes

Delamination - A State-of-the-art Review

(1) Air Entrainment - Incorporation of entrained air in an indoor concrete slab receiving a dense, hard, machine-troweled finish is known to be a common cause for delamination. The higher the air content, and/or the higher (and longer) the finishing pressures, the

Delamination of Troweled Concrete Surfaces | Sterling ...

Avoid dry shakes on air-entrained concrete. Use heated or accelerated concrete to promote even setting throughout slab depth. Avoid placing concrete directly on vapor retarders, if the application allows. Do not use air-entrained concrete for interior slabs that will receive a trowel finish.

CIP 20 - Delamination of Troweled Concrete Surfaces

4. Avoid placing concrete directly on vapor retarders, if the application allows. 5. Do not use air-entrained concrete for interior slabs that will receive a trowel finish. 6. Avoid placing concrete on substrate with a temperature of less than 40° F (4° C). References 1. Guide for Concrete Floor and Slab Construction, ACI 302.1R

Fallacies and Misconceptions Related to Air Entrained Concrete

In reality, the freeze-thaw durability of concrete is related to (1) the size of the entrained air bubbles, (2) the distance the entrained air bubbles are spaced, and (3) the surface area of the ...

Finishing air-entrained concrete requires a light touch ...

Finishing air-entrained concrete requires a light touch. Rachel Detwiler. July 27, 2021. Durability, Insights, Specifications. When finishing air-entrained concrete, less is more. Hard-troweled surfaces and air-entrained concrete don't mix. If you need to entrain air— that is, if the concrete will experience cycles of freezing and thawing ...

Beware of troweling air-entrained concrete floors

Before requiring air-entrained con-crete for interior slabs with a ma-chine-troweled finish, designers should assess: n The risk of concrete scaling due to cold-weather exposure n The cost of air-entrained concrete vs. non-air-entrained concrete n The cost of repairing scaling or other freeze-thaw damage n The risk of delaminations when

7 Tips And Tricks For Finishing Concrete And The Tools You ...

Bull Float or Darby – To flatten edges that may be left after you initially flatten the concrete with the 2×4. Hand Float or Magnesium Float – To create that perfect, flat surface and smooth finish. The magnesium float is best for air entrained concrete. Edging …

Air-Entrained Concrete Patching Mix AE - TCC Materials

voids left by the screed. Hard steel trowel finish is not recommended for air-entrained concrete. 3. Concrete shall be used and placed in final position within 1 hour after initial mixing or discarded at that time. 4. Allow the concrete to reach initial set, wait for all water to evaporate from the surface before finishing with a trowel or ...

(Delamination due to use of air entrainment in a concrete ...

(Delamination due to use of air entrainment in a concrete slab that has received a machine-trowel finish): Cross section of a concrete core from a delaminated slab showing the near-surface region ...

Broom Finish - When & How to Broom Concrete - Concrete …

For concrete with ¾ or 1-inch aggregate, order the concrete with 6% entrained air (plus or minus 1%)-and make sure you are getting it, otherwise the surface will spall. For smaller aggregate you need more air-7% for ½ inch and 7.5% for 3/8 inch. Trowel There's some disagreement here.

CIP 14 - Finishing Concrete Flatwork

Air entrained concrete should not be troweled. If trowel finishing of air-entrained concrete is required by specifications, extreme caution should be exercised when timing the finishing operation. For a smooth floor make successive passes with a smaller steel trowel and increased pressure. Repeated passes with a steel trowel will produce a ...

Walk-behind Trowels Article | Wacker

A concrete mix that contains more than three percent entrained air should be finished by utilizing hand tools and not be given a hard trowel finish with a power trowel. If the entrained air content is higher than three percent the floor can delaminate and cause problems in the finishing steps.

Troweling Air-Entrained Concrete | JLC Online

When troweling air-entrained concrete, the contractor should do the following: Delay each finishing step as long as possible. Keep the surface as "open" as feasible tand finally close the surface as late as possible. When lightly troweling the surface at the end of finishing, "leave some fuzz on the surface," as the finishers say. 2.

Magnesium Hand Float 18" x 3-1/8 pair up with a 16"x4 ...

It is recommended for use with air entrained concrete. One of the reasons why this tool is so popular it is because it produces a smoother finish than wood. 2) A Concrete Finishing Trowel with measurements 16"x4"" and its main features are: Made of Stainless Steel; Cast Aluminum mounting securely riveted to tempered.

Air-entrained concrete for an indoor slab. : Construction

We have a design that calls for air-entrained concrete for a slab. The contractor would like to use non-air-entrained since it is easier to trowel and finish. The slab is indoors, however there is no heat source for the building (it is used as storage), and the climate will be well below freezing in the winter.

Delamination of Troweled Concrete Surfaces — …

Do not use air-entrained concrete for interior slabs that will receive a trowel finish. Avoid placing concrete on substrate with a temperature of less than 40°F (4°C). References. Guide for Concrete Floor and Slab Construction, ACI 302. 1R American …

Float and Trowel Finishes - Artisticrete

Float and Trowel Finishes. Prior to the introduction of power tools, a floated finish was that produced by a large, generally wooden or sometimes metal, hand float moved over the surface when the concrete was still plastic. This produced a flattish slightly textured surface which often contained float marks. Nowadays, the operation is carried ...

CIP 2 - Scaling Concrete Surfaces - Geiger Ready Mix

4. Use correct timing for all finishing operations and avoid the use of steel trowels for exterior concrete slabs. 5. Specify air-entrained concrete. In cold weather, concrete temperature should be at least 50°F [10°C], contain an accelerating admixture, and be placed at a lower slump.

Only use Walk Behind Power Trowels for Lightweight Concrete

So the adage that you shouldn't use a power trowel on air-entrained. Concrete doesn't apply in the case of lightweight concrete; you can use a power trowel, but only with proper timing. A typical fire-rated lightweight mix calls for compressive strengths between 3500 and 4000 psi. Most lightweight concrete is pumped, with 4000-psi mixes ...

COLD WEATHER CONCRETE GUIDE FOR STRUCTURAL …

• Avoid hard-trowel finishing air-entrained concrete (3% or greater) as this can lead to surface blistering or other surface defects. Therefore, air-entrained concrete should not be specified for hard-trowel slab construction.