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Hot Weather Concreting: How to Avoid the Problems that it Presents

The Perils of Concreting During
Hot Weather And How To Avoid Them

Hot weather concrete pouring can cause a myriad of problems. Many people think it is just about the heat itself but there is more to it than that. Many factors affect the quality and success of concreting during hot weather conditions. Hot weather, as defined by ACI 305R is any combination of the following:

  • High ambient temperature above 90 degrees
  • High concrete temperature
  • Low relative humidity
  • High wind speed
  • Solar radiation

The heat is not the problem as concrete cures through hydration and not temperature. However, when the concrete becomes hotter than 77 degrees, it speeds up the hydration timing. If the concrete isn’t hydrated properly, it will be weak, crack easily and be more susceptible to damage from freezing and thawing. Construction crews must prepare for hot weather concrete placement.

Ways to Prepare for Pouring Concrete in “Hot Weather”

  • Crews should avoid pouring the concrete during the hottest part of the day. Tracking hour by hour temps can assist with this determination. It is also wise to avoid extreme temperature changes. Pouring concrete on a hot day when followed by a cool night can cause thermal cracking to ensue.
  • A team of workers should be available to ensure that the work is finished quickly and efficiently. Truck delivery should occur early in the day and a group of laborers ready to start immediately. Check for any potential delays so that the task will be completed in a timely manner.
  • Sunshades, windbreaks or mist fogging can be used to protect and slow down the process of the concrete curing too quickly.
  • Extended set additive, moderate heat cement and blended cements can provide solutions to pouring concrete in difficult conditions.
  • Keeping concrete in the shade before pouring or using an evaporative retarder may help as well.
  • Once the water is added to the mix, reduce the mixing time.
  • Ice or cold water can be added to the mixture to cool down the concrete. Cold water can reduce the heat of the concrete by about 10 degrees and ice by approximately 20 degrees.
  • If a slab is being poured, putting cool water on the sub-grade is another neat trick.
  • Control-joints can be spaced closer together to aid in strengthening.
  • Steel Fiber Concrete can be used to make slabs to add after walls and roofs are built out. Adding steel fiber to concrete has advantages and disadvantages so do your homework before choosing this method.
  • Extreme weather conditions may require the infusion of liquid nitrogen into the mixers. This solution can be costly as there are concerns about damage to blades and precautions must be taken.
  • There are several curing methods that can be used. Understanding these methods directly impacts how successful your curing process is.  Concrete companies will want to have a plan ahead of time as to the correct method for each individual situation and to follow through with recommended procedures.

Setting concrete in difficult situations is a complicated process. However, with a little research and a lot of preparation, a concrete job can have favorable results.

By admin Asphalt Paving • • • • 0 Comments

7 Advantages of Choosing a Concrete Parking Lot for your Business

Don’t underestimate the value of a great parking lot to your business. From prospective clients to potential employees, your parking lot is a big part of the first impression your building makes. Obviously, you want that impression to be a good one. An adequate number of spaces is just the beginning. The parking lot should also be a safe environment for guests.

Asphalt is a popular car park material. It is inexpensive and quick to install. Smart business owners think long-term, however. More and more companies are choosing a concrete parking lot instead. Here are seven reasons to consider a concrete parking lot, even if the bid is a little higher:

 

1. Stronger

Concrete is far more durable than asphalt. It keeps its form without buckling even under the weight of heavy traffic and heavier vehicles. If you expect high traffic or visits from a lot of trucks, concrete is the material that can take the beating.

 

2. Longer-Lasting

As a business owner, you have a keen eye to “return on investment.” A lower price tag is not a great value if the product has to be replaced in half the time or less than the pricier option. In this case, concrete lasts far longer than asphalt, making it a better investment long-term.

 

3. Better-Looking

Don’t forget that crucial first impression. Even a basic concrete parking lot typically looks better than its asphalt cousins. Better yet, concrete can be textured, colored, and decorated to create a unique, appealing aesthetic customized to your business.

 

4. Better for the Environment

Most of the materials in concrete are natural and chemical-free. “Sustainable concrete,” which contributes to a stable rainwater cycle, is available as well. In the summer heat, asphalt parking lots soften and seep oils and chemicals, becoming unpleasant and unsafe to walk on. A concrete parking lot absorbs less heat, which keeps the office park from turning into a “heat island” that damages the local flora and fauna.

 

5. Low-Maintenance

Asphalt requires annual service and preventative maintenance. Concrete parking lots need service far less frequently. If you have enough to keep you busy at your company without having to schedule service calls every year, a concrete parking lot is the way to go.

 

6. Better Lighting

Asphalt is black or dark gray because it absorbs more light than it reflects. In contrast, concrete reflects three times as much light as asphalt. This reflected light reduces the amount of electric light required to keep the parking lot well-lit. A well-lit parking lot is crucial for safety, as it deters crime. Easy lighting also reduces electric bills.

 

7. Long-Term Cost Savings

Lower utility bills. Less maintenance. Longer lasting. You can probably see a pattern emerging. Yes, the initial installation cost can be higher and more time-consuming. Over the long term, however, the costs associated with a concrete parking lot can actually be a lot lower than an asphalt one, in terms of both cash and time expenditure.

 

 

Installing or replacing a parking lot is a critical investment in the life of a business. Remember, the best solution isn’t always the least pricey solution. From eco-friendliness to cost savings, consider the long-term advantages of a concrete parking lot.

 

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Common Concrete Issues

Concrete is a common material used due to its durability and versatility. Under the right conditions, it is a sustainable material. But, there are numerous common concrete problems, which can prevent concrete from attaining its longevity. Recognizing these problems and understanding the solutions can improve the overall performance of concrete. The common concrete problems include dusting, blistering, plastic shrinkage cracking, discoloration, and scaling.

Dusting

Dusting on concrete occurs when a hardened concrete surface appears as a powdery material. Laitance, which is a layer of cement, water, and fine aggregates is the primary reason why dusting occurs on concrete. The laitance layer is weak, porous, and thin. As a result, the laitance makes the hardened concrete surface vulnerable and weak.

Other reasons why dusting appears include improper cure of the concrete surface, exposing the concrete to carbon dioxide while it is in a plastic state, and conducting finish operation on the concrete surface while it still has bleed water—this is water that separates itself from the concrete.

To avoid these problems, proper concrete curing procedures should always be followed; equipment that produces carbon dioxide should always be vented while the surface is in the plastic state, and the finishing operation should always be conducted on the concrete surface after bleed water has been removed.

Blistering

Blistering appears on a hardened or fresh concrete surface as bumps. These blisters occur when bleeding water or entrapped air rises to the sealed concrete surface. Blistering of concrete surfaces is problematic, as it causes the concrete to break easily under stresses like traffic. Other reasons why blistering occurs include excessive or inadequate use of vibration during concrete compaction, setting concrete surfaces over the vapor barrier, and sealing the concrete surface early.

To prevent blistering from occurring, appropriate concrete compaction procedures have to be followed, if possible, concrete should not be placed over vapor barriers, and trowel blades must be kept flat at all times to avoid sealing the concrete surface early.

Plastic Shrinkage Cracking

Plastic shrinkage cracking occurs when a crack appears on fresh, hardened concrete surfaces. Like the name suggests, these cracks develop while the surface is still in the plastic state. These cracks occur when the concrete surface experiences a rapid loss of water before it sets. Although plastic shrinkage cracking is an aesthetics issue and not a structural issue, these cracks end up allowing chemicals to penetrate the surface, and this can result in structural problems later on.

The loss of water on concrete surfaces can occur due to several reasons like low relative humidity, high winds, and high concrete temperature or ambient air. To avoid these conditions, ensure you use fog spraying equipment, windscreens and windbreaks should be installed, and always avoid placing concrete at midday.

Discoloration

Discoloration of concrete can occur due to various reasons like material exposure, weather conditions, and even the curing time. Although concrete discoloration may look aesthetically unpleasing, there are numerous ways you can repair these issues. The first method is using a concrete cleaner. These will help give the concrete a better and natural look. If that does not work, you consider using a concrete stain.

Scaling

Scaling on concrete surfaces occurs when the surfaces start to chip or flake away. This is usually because of freeze-thaw, water seepage, poor concrete finishing, or weak concrete surfaces. To repair scaling issues, use trowel-grade light coat, as it helps fill the scaled area. Also, ensure that you seal your concrete at all times, as this helps to reduce scaling significantly.

By admin Asphalt Paving • • • • • • • • 0 Comments

How to budget for your parking lot updates in 2019

Parking lot management may not be too involved, but smart owners create a strategic plan for preventative maintenance and upkeep at the start of every year. If you want to take a proactive approach to your parking lot budget, consider these tips when determining your budget for parking lot updates in 2019. Utilizing a trusted partner in this process can cut down the time commitment on your part, and leave you with the bandwidth to concentrate on the immediate needs of your business.

Where is your pavement in the useful life cycle?

Pavement does not last forever and requires regular upkeep and maintenance. Whether your parking lot is need of sealing, patching, or it’s time for replacement, it’s important to approach this upkeep in a proactive manner. In addition to having an adequate amount of funds available, it is also important to remain proactive in order to minimize disruption to your cash flow as repairs and maintenance are conducted. Undergoing an inspection is an effective way to determine the most impactful update projects while scheduling them when the downtime will cause the least possible impact on your cash flow.

Is preventative maintenance and upkeep a part of your 2019 budget? It should be.

The physical condition of your parking lot is the foundation of your business, and including the upkeep of your lot in your 2019 budget is essential. In addition to regular maintenance it is key to have reserves in place should the need for a major refurbishment or repair arise. Without a proper budget, you may be left scrambling in the event of an unseen event or emergency. Don’t let this happen to you! Proper maintenance and regular updates can prevent future issues that grow more expensive with neglect. By adding such line items to your 2019 budget you will be ahead of the curve and in a much stronger position if an unexpected repair need arises at your parking lot.

Determine your top 3 goals or “must-dos” to increase your customers’ parking experience in 2019

The start of 2019 is a perfect time to review your goals for the year and put them into action. Whether it is reconfiguring the lot to maximize space, or updating payment options for your customers, this is the right time to put those plans in place. When you budget and plan for future improvements your parking lot is much less likely to experience downturns and dips in revenue caused by being off-line. Tackling these top 3 goals for 2019 with a schedule that includes a budget for the necessary funds can help you to avoid damage and repair in the future.

Create ongoing relationships with a trusted partner in order to maximize results

The day-to-day running and management of your parking lot holdings can take up a lot of your time, and bringing in a trusted partner can yield positive results. With the right partner, you can focus on the business aspects of your parking lot and leave the budgeting and planning to a specialist. Thinking that you don’t have enough time to properly plan and budget for updates to your lot can lead to a lot of avoidable trouble down the road.

Make 2019 the year that you implement proper budgeting and maintenance plans for your parking lot. Proper maintenance, repair, and updates can help you to maximize profits while minimizing downtime and unexpected expenses!

By admin Paving • • • • • • 0 Comments

What Temperature Should You Pour Concrete?

Concrete can be poured at any time when the temperatures have been above 40 F for over 72 hours. Moderate temperatures make the placement crew’s job easier as it sets up at a good pace, allowing ample time for edging, jointing, troweling and curing. In some instances, it can be placed when temperatures are lower but special additives are used, and heating may also be required. The other factors that can affect concrete pouring include wind speed, humidity levels, and the temperature of the sub-base which is the surface you will be pouring your concrete on.

Pouring your concrete in cold weather

In regards to concrete, cold weather is anything below 40ºF. Here are some tips for pouring concrete in cold weather;
  • Should the sub-base be frozen thaw it with heaters. Alternatively, you could pour the concrete on Styrofoam material as it helps sustain the temperature in the concrete.
  • Order for concrete products that are designed to cure promptly. Cold weather concrete is capable of resisting thawing and freezing effects as they have air entrained voids.
  • Ascertain that the concrete you order for has a low slump also known as a drier mix to minimize bleed water. You can use a vacuum or squeegees to rid the concrete of bleed water. This will help decrease the setting time.
  • You could use hot water to mix the concrete or use extra cement, that is, 100 lbs per cubic yard of concrete to create a heated reaction.
  • Once you have successfully poured your concrete, maintain its temperatures at 50ºF for a minimum of 3 days to a maximum of 7 days. This can be achieved through the use of heated enclosures or an insulating blanket.
  • If you are going to make use of a heated enclosure, ascertain that it is weatherproof and windproof.
  • Once you determine that the concrete is well set, you can remove the insulating blanket or the heated enclosure to allow the concrete to air dry.

Pouring your concrete in hot weather

  • Hot temperature in regards to concrete pouring is anything above 77ºF. Here are some tips for pouring concrete in hot weather;
  • Avoid pouring the concrete when it’s too hot to avoid temperature-related issues. You can do so either early in the morning or late in the evening.
  • You can erect shades along with wind barriers to protect the poured concrete from crusting or stiffening. Crusted concrete is highly susceptible to plastic shrinkage, crazing, and cracking.
  • Have a few people help you with the mixing process. Prolonged mixing only results in increased temperatures. You can add ice to the water mix to cool the temperature of the mixture.
  • You can dampen the sub-base to help minimize its temperature before pouring your concrete.
  • You can control the evaporation after pouring through the use of wet burlap, polyethylene sheets, waterproof paper, and windbreaks.
  • Should the weather be extremely hot, you will need to observe continuous moist curing for the next couple of days until the concrete is dry.

Finally, note that it is not advisable to place concrete when temperatures exceed 100 F, as it can flash set and there won’t be enough time for proper finishing.