NRI Bridge Report

Material Usage and Condition of Existing Bridges in the U.S. reports that 72,749 of the U.S. bridges studied were structurally deficient. More than half of the deficient bridges were constructed with structural steel.
Download the report

 

 Accelerated Bridge Construction:  A workshop was conducted at the 2006 Concrete Bridge Conference in Reno, NV to develop guidance on what is needed to further implement accelerated bridge construction nationwide.
Click here for a summary report (PDF).

  

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Cold Weather Concrete

10 Tips for Pouring Concrete in Cold Weather

2. Use air-entrained concrete.

3. Don’t place concrete on a frozen subbase. Be sure that all ice, snow and frost are removed from surfaces the concrete will touch. Thawing frozen ground is highly recommended. 

4. For max durability & strength, fresh concrete should be kept at 55ºF or higher for thin sections. Consider using high-early strength concrete.

5. Cure concrete to prevent loss of moisture. When heated enclosures are used, provide extra moisture by sprinkling or use steam for heating. Vent salamanders and other fuel-burning heaters. Concrete should be allowed to cool slowly to prevent thermal cracking. Best solution we’ve observed is a wet cure concrete curing blanket with insulated backing. 

6. Do not use “antifreeze” compounds in an attempt to lower the freezing point of concrete.

7. Leave the forms in place as long as the job schedules permit. Reshoring is necessary until concrete reaches required design strength.

8. Keep job condition records. Record, at least twice daily: weather conditions, temperatures of the air and the concrete surface.

9. If the concrete is to cure below 60ºF, water reducers or retarders may prolong the set.

10. The use of calcium chloride or admixtures containing soluble chlorides is not recommended under certain conditions. Concrete curing blankets are always prefered.

Ideally, concrete should cure for 7 days at temperatures between 65-85°F, with humidity levels under 100%. Due to seasonal weather changes, ideal conditions rarely occur naturally.

 Use Powerblanket™ Concrete Curing Blankets

Pouring concrete slabs can be a challenge even in ideal weather conditions. Cold temperatures can increase the risk that your concrete will not cure properly. Proper concrete curing is a key to a strong, long-lasting concrete slab.

Never pour concrete on frozen ground. Use powerblanket™ or other ground thawing electric blankets to bring the temperature up to at least 65°F. Why? Not only can the ground freeze the concrete from the bottom up, cracking can occur when the ground thaws. Hollow spots under the concrete may also be created – and driving over the hollow spots will create tension which in turn creates cracks.

Likewise, never pour concrete over snow – you’ll simply add unnecessary water to the concrete.

If you’re pouring a foundation slab, temperature control is even more critical. A foundation wall is simply a vertical slab – but it’s exposed on three sides once the forms are pulled. Foundation forms should be protected with powerblanket™ or other concrete curing blankets for at least three days, depending on weather conditions.

If you remove forms too quickly, your foundation walls will have less protection, especially if you also remove the concrete curing blankets. Temperatures below 14°F completely stop the hydration (crystal growing) process, demanding the use of curing blankets or other meothods of applying heat.

If the walls are backfilled before proper curing has taken place, the concrete may not be strong enough to withstand the pressure. Once temperatures rise above that point, the chemical reaction resumes, but very slowly. It could take a long time for your foundation walls to gain enough strength to resist the pressure of backfill dirt.

Use Low Slump Concrete

Low slump concrete is hard to work with, but in cold weather it can mean the difference between success and failure. While labor costs can be higher, you’ll have less water bleed problems, and you can place the powerblanket™ concrete curing blankets on the slab more quickly, reducing the effects of cold weather.

 

 

Concrete Blanket Basics

Most concrete curing blankets do a good job of curing concrete, protecting slabs, and curing newly-laid brick or block walls… some however, fall flat on their face.  We review the top 10 curing blankets in our review sections. Curing blankets allow work to proceed on schedule and for concrete and mortar to cure rapidly and efficiently, maximizing finished strength and durability even in extemely cold conditions. Contractors and builders use concrete curing blankets to keep their jobs on schedule and under-cost; highway construction companies use curing blankets to meet state codes and keep their projects moving. 

Because of their simple and economical design, concrete curing blankets are also used in a variety of other applications by small companies and individuals. They are useful in virtually any situation where cold weather causes schedule delays or damage.

Concrete curing blankets are easy to use and maintain and don’t create environmental hazards: no noxious fumes, no open flames, and no toxic emissions.

Shopping results for concrete blankets

Power Blanket Concrete Curing Blanket 25′ x 6′ $745.00 new – Amazon.com Powerblanket Multi-Duty Concrete Curing & Ground Thaw Blanket 23ft … $1,699.99 new – NorthernTool.com Concrete Curing Blanket $39.99 new – eBay

A well constructed concrete curing blanket will eliminate the cold weather variable in a variety of horticultural, agricultural, landscaping, or construction settings: and with an electric curing multi-duty blanket you can quickly and easily thaw frozen ground, protect germinating seeds and bulbs, and minimize the effects of late-season snow or ice. Electric curing blankets can quickly unthaw frozen ground, making it easy to work. Curing blankets can also keep the ground from freezing, protecting from the effects of freezing weather, snow, or ice. Concrete curing blankets can also be used to protect newly-poured concrete, brick, or stone walkways and paths, ensuring optimal curing temperatures and a long-lasting, durable product. 

Always be sure to thaw frozen ground before pouring concrete. Never pour concrete on frozen ground unless you’re looking for a nightmare of a headache.  Plan your work and work your plan.  You can effectively keep your crews working all winter long with a good curing blanket.  Electirc thaw/cure blankets will help kill 2 birds with one stone and allow you to eliminate frost before proceeding with flatwork projects.

Top Rated Concrete Curing Blankets

We have assembled a list of the TOP 10 Concrete Curing Blankets on the market.  Give us your feedback and experience with these brands and we’ll post your comments on the website.

TOP 10 CONCRETE CURING BLANKETS

POWERBLANKET: http://www.powerblanket.com (Editor’s Choice) 5 Star

EAGLE: http://www.eagleind.com/site.php

REEF INDUSTRIES: http://www.reefindustries.com/products.php?id=4&tsid=googleppc

DALCO: http://www.dalcoindustries.com/index.php/pagetype/products/id/1241.html

FLATWORK: http://www.flatwork.com

MIDCO: http://jcsmithinc.net/jcsmith/prod_pgs/concrete_blankets.htm

PREGIS: http://www.pregis.com/ConcreteCuringBlankets/Products/tabid/545/language/en-US/default.aspx

GREENHEAT: http://www.greenheattech.com

COVER-TECH: http://cover-tech.com/curingblankets.htm

TOPPER: http://www.insulationsolutions.com/products/topper/information.html