The Role of Calcium Chloride in Concrete

Strong and durable, concrete is suited for virtually any exterior surface, while being one of the most affordable building materials. It is a mixture of Portland cement, water, and aggregates such as sand, rock, or gravel. It does have limitations, but adding calcium chloride allows the mixture to set more quickly and increases its initial strength. For concrete contractors, it improves performance and reduces costs.

Calcium chloride accelerates cement’s rate of hydration. A reduction in setting time helps protect freshly placed concrete. The effect is most noticeable in cool weather. Ready-mixed concrete sets more slowly at temperatures below 70°F, and even more so between 30°F and 50°F. This means concrete construction can continue in the fall and winter, and that contractors can still ensure quality work.

Here is a more detailed look at how calcium chloride contributes to high-quality concrete:

Effects on Chemical Properties

  • Accelerated Heat of Hydration: When calcium chloride is present, the heat of hydration occurs at a faster rate, so concrete can hydrate in 10 to 12 hours.1 The total increase in hydration rate isn’t always substantial. It is more noticeable in temperatures below freezing, at which the free water content of fresh concrete is lowered faster.
  • Control of Aggregate Swelling: Concrete can deteriorate due to aggregate swelling when high alkali cement is used with certain aggregates. Calcium chloride can further promote this reaction. However, if it must be used, low alkali cement or a non-reactive aggregate is recommended.
  • Reduced Resistance to Sulphate Attack: Sulphates can react with calcium and aluminum ions, resulting in the formation of substances that disrupt the concrete. These include calcium sulfate and calcium sulphoaluminate hydrates. Calcium chloride can reduce resistance to this process.

Effects of Calcium Chloride on Concrete

Men Working on Residential Driveway

The addition of calcium chloride to a concrete mixture in residential and commercial applications has the following effects in its physical properties:

  • Setting Time: Adding calcium chloride to concrete can reduce its setting time by up to two-thirds. With a 2% admixture of chloride at a temperature of 50°F, set times attainable at 70°F without the additive can be achieved.2

Standards differ on the setting times of calcium chloride. Per the requirements of ASTM C494-1971 and CSA A266.2-1973, the initial setting time (when calcium chloride is used), should be accelerated by a minimum of 1 hour (The ASTM standard requires setting to be completed within 3½ hours, while the CSA standard requires it within 3 hours).3

  • Water Cement Ratio: Calcium chloride can induce early stiffening of concrete, thereby reducing bleeding (water content rising to the top), but it does not reduce the quantity of water required to achieve a given slump or consistency. As far as the water to cement ratio, chloride does not have a significant impact on strengthening.
  • Freeze/Thaw Resistance: The rapid hardening of concrete provides early resistance to freeze/thaw damage. However, calcium chloride may leave matured concrete less resistant. Nonetheless, this property is significant during the winter when freshly laid concrete may be exposed to de-icing salts.
  • Air Entrainment: Less air entrainment agent is needed to produce more air content when calcium chloride is introduced. The chloride itself doesn’t cause entrainment of air.

Is Calcium Chloride Bad for Concrete in Any Way?

In addition to reduced sulfate resistance and a boost in aggregate swelling, calcium chloride can increase dry shrinkage. The contraction of hardened concrete with the loss of water can cause cracking and warping. Calcium chloride is known to increase this process. By how much depends on the type of cement, the amount of additive introduced, the curing period, and environmental conditions.

The accelerant can also trigger efflorescence. In some cases, a whitish deposit can form on cured concrete surfaces and this is not water-soluble. The deposit can be removed with diluted hydrochloric acid.

Calcium chloride can also cause corrosion of reinforcement steel. The steel is less protected when moisture penetrates the concrete, as it starts to carbonate and lose its alkalinity with exposure to air. The large surface area of the wires and greater stress differences contribute to corrosion as well.

Effects on the Mechanical Properties of Concrete

Concrete Pouring

The primary mechanical impacts of calcium chloride include a gain in compression strength, especially at lower temperatures. It accelerates the hardening rate of concrete. The strength gain in the first three days may vary from 30% to 100%. However, concrete strength can decline if the amount is higher than accepted standards.

Per ASTM C-494, an increase of at least 125% at three days, over a control concrete sample, is required. This is only 90% at six months to one year after installation.4

Advantages

In summation, the advantages of adding calcium chloride to concrete on, for example, a residential concrete driveway, include:

  • Accelerated rate of set
  • Increased initial strength
  • Prevention of freeze damage
  • Reduced bleeding
  • Faster workaround time
  • Reduced costs
  • Improved workability

When calcium chloride is added, concrete can bear loads much sooner. It is also beneficial when used with fly ash. Replacing up to half of Portland cement with fly ash can increase costs, but adding the accelerator helps. However, it is a concern when calcium chloride accelerators are prohibited under such circumstances.

How Chloride Is Added

Calcium chloride is available in many forms. It can be obtained in the form of pellets and other granules, while its flake form is also common. The flake form must consist of a minimum of 77% calcium chloride; 3¼ pounds of granulated chloride must have at least 94%.5 Solutions are recommended because all forms of calcium chloride are soluble in water.

A solution should not be in direct contact with cement, as it will set more quickly. The recommended process is to dilute the solution in water and then mix it with aggregate.

Cross Construction Services: Concrete Installation and Repair in Houston

Finished Residential Concrete Driveway

We are experienced and trusted commercial and residential concrete contractors near you, providing patio, sidewalk, parking lot, and concrete driveway repair in Houston, TX. Concrete is a versatile material. Our over 30 years of experience, quality of work, and commitment to delivering projects on time and on budget help our clients benefit even more from our concrete service. Minimizing disruption to homes and businesses is also our priority.

Cross Construction Services is a premier concrete construction, inspection, and renewal company in your area. Call 713-254-1703 today to schedule concrete repair in Houston or obtain a free estimate.

Sources:

  1. http://web.mit.edu/parmstr/Public/NRCan/CanBldgDigests/cbd165_e.html
  2. http://www.tetrachemicals.com/Products/Calcium_Chloride/Applications/Ready_Mix_Concrete_Acceleration.aqf
  3. http://web.mit.edu/parmstr/Public/NRCan/CanBldgDigests/cbd165_e.html
  4. http://web.mit.edu/parmstr/Public/NRCan/CanBldgDigests/cbd165_e.html
  5. http://web.mit.edu/parmstr/Public/NRCan/CanBldgDigests/cbd165_e.html

Questions to Ask your Concrete Driveway

Concrete contractors aren’t all one and the same. There’s no one-size-fits-all approach to concrete driveway repair, and any contractor must know providing quality work requires fully understanding your project.

When searching for commercial or residential concrete contractors near you, it’s wise to ensure the company is committed to high-quality customer service. Here are some important questions to ask your concrete service contractor, so you know their experience in residential and commercial work and what to expect before, during, and after the project.

What Kind of Experience Do You Have?

Concrete Driveway

Inquire about their years of experience in the field and the kinds of concrete construction projects they have completed. You can start by narrowing down your selection by reading reviews. Unless you interview a potential contractor, you won’t fully know whether they’re suited for your project. Better yet, seek contractors affiliated with reputable businesses specializing in, for example, commercial and residential concrete driveway repair near Houston, TX.

Can I See Your Portfolio of Past Projects?

Reviewing examples of the contractor’s past work helps you judge their quality and experience. If they refuse to show you a portfolio of concrete driveway resurfacing projects or evade the question, this is reason for suspicion. A reputable professional will refer you to their digital portfolio or, if you meet in person, show a series of photos on their desktop computer, laptop, or phone that exemplifies their body of work.

Do You Have References?

There may be instances when the contractor doesn’t have pictures of their previous work immediately available. Nonetheless, you can continue the conversation. Follow up with a request for references; you can also get more information by contacting previous clients. This not only allows you to get first-hand information from other customers, but it also allows the contractor to share their pride in having a list of satisfied clients.

What Is Your Current Schedule?

Man Getting Facial Treatment

Knowing the contractor’s current schedule enables you to assess whether they can meet your deadline. If a quick turnaround is your priority, then you need this information. Also take into account that, if the company is reputed for quality work, they’ll understandably have a full calendar and need to schedule your project in advance.

What Is the Time Frame for My Project?

This also helps you assess a company’s experience and compare it to others. Your contact should have a good idea as to how long a project like yours will take. For example, a residential concrete driveway shouldn’t take more than two or three days, while commercial sidewalks, concrete walls, and other more extensive projects can take much longer. If one company’s estimates differ greatly from others, it’s probably a good idea to move on.

Will a Permit Be Required for My Project?

A contractor experienced in concrete construction should be familiar with the permitting process. Knowledge of the permits required for your project is necessary to produce the quality of work you’d expect. If residential concrete contractors near you can’t answer your permit-related questions, they likely lack the necessary experience.

Will the Concrete Be Reinforced with Rebar or Other Supports?

Man Working on Rebar Reinforcement

This is a good way to test the contractor’s knowledge of concrete driveway construction. The question shows your level of knowledge and lets you assess what they know. Rebar reinforcement helps support a concrete surface when the expected weight and pressure of objects is high. Plus, the more you know about the company’s process, the better informed you’ll be before signing off on the project.

What Protective Measures Do You Use?

This question provides a glimpse into their training and experience. There are many guidelines and regulations regarding work-site protection. Safe work practices can reduce the potential for delays in your project. Inquire about workman’s compensation and liability insurance, too; these can cover expenses should there be any type of job accident, which you might otherwise have to pay for.

Do You Manage the Entire Project?

Whether you’re looking for residential or commercial contractors near you, it’s important to know who is managing the project. This gives you an idea of how many concrete professionals will be on your property and who is in charge. Any experienced, organized contractor should be able to easily answer this question. If they can’t, then the contractor probably lacks the experience needed to take on your project.

Do You Provide a Written Agreement?

Man Pouring Concrete

The written agreement should outline every detail, from deadlines to concrete driveway thickness, to prices per square foot. The contract should also indicate who is responsible for individual tasks. If you later have questions on the type or quantity of work done or the quality of service, then you’ll have a reference for what was promised to fall back on. A guarantee on the work performed can protect your investment if the work doesn’t meet predefined requirements and expectations.

Call Cross Construction Services for Concrete Repair and Installation

At Cross Construction Services, we can answer all your questions honestly and in detail. Our contractors specialize in concrete driveway repair and install concrete per the latest standards and best practices. You can trust our commercial and residential concrete driveway contractors to prepare your property, stabilize the underlying ground surface, and install quality expansion joints, not to mention fix cracks and uneven slabs and apply durable sealants. We also provide concrete leveling and install concrete for patio rooms and other outdoor living spaces.

If you’re looking for residential or commercial concrete installation or repair in Houston, TX, contact us for a free estimate and to schedule a consultation and start date.

5 Pros to Using Concrete for Your Houston Driveway or Patio

Concrete is a highly versatile and durable solution for driveways and patios. A longer-lasting alternative to gravel driveway repair in Houston, concrete installation is beneficial in many ways. Cross Construction Services is a leader in concrete services, from construction to inspection and renovation. One of the leading concrete companies in Houston, Texas, we are committed to quality work and delivering projects on time and on budget.

When you need a concrete driveway or patio installed, you can count on us for an all-in-one solution that includes planning the project and procuring all the concrete needed. A properly designed concrete surface can improve curb appeal. To boost the value of the results, we also focus on ground stability and leveling, installing expansion joints, and fixing imperfections such as cracks and uneven slabs or drainage issues. We can reliably seal and re-surface concrete as well.

resurface concrete driveway

Why is concrete the best solution for patio or driveway installation? Here are five reasons why you should consider it over other materials, including asphalt.

1. Versatility

Concrete, which is used for residential applications and in business centers, shopping malls, food service establishments, warehouses, and more, is highly versatile. It is extremely resistant to variations in temperature and can withstand high heat compared to asphalt that softens and even melts. Properly sealed and maintained concrete can even hold up in extremely cold temperatures.

A strong material, concrete can withstand high traffic. That’s why it’s often used for shopping center parking lots. It can maintain integrity in heavily trafficked areas, providing safety for drivers and pedestrians. You can be rest assured our durable concrete solutions used for driveways will improve the quality of your screened-in patio or sunroom or outdoor living space.

 2. Suited for Hot Climates

Although untreated concrete can crack in extreme cold and be damaged by salt and deicers, it can tolerate temperature extremes if properly installed and sealed. Asphalt shrinks and expands with fluctuations in temperature and can easily crumble in high heat. The main difference between concrete and asphalt is how the aggregate is bound together. Asphalt is held together by a petroleum-based substance, while concrete is a mixture of crushed stone and sand bound by cement.

A hot climate does not put excessive stress on a concrete surface. If you live in an area that has long, hot summers and mild winters, concrete is the best solution. Asphalt softens up in high temperatures and can even stick to shoes and tires. Heat can degrade it along the edges, and the surface can even become indented from contact with vehicle tires.

3. Long Lifespan

Concrete can last 25 to up to 30 to 40 years.1 Most other surface materials won’t last that long, especially gravel driveways. Extremely durable, concrete can go many years without requiring a major overhaul. Substitute a plastic over a metal snow shovel, and you can avoid unnecessary damage, while acrylic sealers can offer protection against manmade damage and natural elements.

However, sealing is not required. It all depends on where you live and how your property is used. If you don’t need a sealant, some costs can be saved, but it can extend the life of your concrete. Although concrete must be at least four inches thick, adding one inch of thickness increases the load-carrying capacity by about 50%.2 When the material is at the end of its usable life, it can be recycled and installed all over again.

concrete installation

4. Ease of Maintenance

If you’re looking for minimal maintenance, concrete can meet your expectations. As stated earlier, it does not require resealing, but a reseal job every five years can extend its life (by contrast, asphalt must be resealed six months after the initial installation, and then every three to five years).

Driveway sealing is a good way to prevent stains and make a concrete surface resistant to salt and deicing chemicals. The only required practice is regular pressure washing. It can improve the appearance of the surface by removing fluids that have leaked from vehicles, discoloration due to mold and mildew, and leaves that pile up in the fall.

5. Can Be Resurfaced

Over time, cracks, gaps, and uneven segments can degrade a concrete driveway in Houston. Crumbling edges and poor drainage can take a toll as well. Small cracks and holes can be patched up, but it is often hard to hide areas that have been treated. A complete resurfacing can be costly, but, with the entire top layer removed and replaced, any crack or break can be hidden.

At Cross Construction Services, our experienced technicians can restore your concrete driveway or a parking lot by addressing minor issues early. Our team performs a complete assessment before doing any repair work. The latest processes and materials are used, while we can address defects in expansion joints, drainage, plumbing, and retaining walls or hand railings.

concrete driveway

Hire Cross Construction Services

We are experts at installing home concrete driveways and patios to optimize your living space for enjoyment during long, hot Texas summers. The durability of concrete cannot be beat. When cracks develop, we can repair your patio or driveway to ensure it is safe for you and your family.

Whether you require patching, resurfacing, or replacement, our specialized team can do the work and leave behind exceptional results. If you’re looking to benefit from the durability, versatility, and longevity of concrete for your home or business, contact Cross Construction Services today at 713-254-1703 or contact us online for a free estimate.

Sources:

1. https://www.homeadvisor.com/r/asphalt-vs-concrete-driveway/
2. https://www.homeadvisor.com/r/asphalt-vs-concrete-driveway/

5 Tips to Lengthen the Life of Your Concrete Patio

A concrete patio is a luxury that turns your outdoor living space into somewhere to gather, entertain, or enjoy a book or snack in the fresh air. The downside is it’s vulnerable to the elements. Weather extremes such as hot and cold temperatures and rain, snow, and hail can take a toll. General wear and tear can affect concrete over time, as well. Once cracks appear, they can expand and, eventually, cause your concrete to crumble.

When well-cared for, concrete can last for two or three decades and sometimes up to 50 years or longer. However, the long-term durability of your patio is dependent on how well you maintain it. You can add years to the life of concrete surfaces and the functionality of your patio with these tips:

1. Allow Enough Time to Let the Concrete Cure

Concrete dries best in warm temperatures. It helps to schedule your patio project when temperatures are forecast to remain consistently warm. The more optimal the temperature and moisture content of the concrete is during curing; the more desirable its properties will be.

Proper curing enables concrete to harden to its full strength. It involves chemical reactions within the cement that help it bind. A reaction between water and cement, known as hydration, also occurs, which generates heat as the concrete is drying.

So, how long does the process take to complete? If you’re just concerned with walking on the surface, it’s best to wait seven days. Heavy vehicles and equipment should be kept off the surface for at least 30 days.

2. Maintenance

As was stated earlier, maintenance is essential for any concrete patio. This can significantly improve its longevity, so it’s vital not to ignore regular upkeep. The best forms of maintenance include:

  • Cleaning: Not all homeowners know how to clean a concrete patio. Without cleaning, water, soil, and contaminants with a high mineral content can erode the concrete. To prevent this, use a garden hose with a spray attachment, or a pressure washer, to clear away dirt and debris about every week or two. Stubborn spills can be treated with liquid dish soap, then scrub the concrete with a broom before applying a water spray.
  • Inspections: By regularly inspecting concrete, you can find cracks in its early stages and take the appropriate measures. The problem will only get worse over time. The best times to check your concrete include late in the summer season when expansion due to heat may have generated cracks. During the winter, freeze-thaw cycles can put concrete under stress. Ground settling, expanding tree roots, water intrusion, and rust formation can worsen crevices, so take a glance now and then to prevent against future high-cost repairs.
  • Sealing: Whether there are cracks or not, sealing the concrete can help protect it and extend the life of your patio. Sealers can prevent dirt, oil, and grease from causing stains, as well as stop water, snow, and ice from getting below the surface layer where they can cause severe damage during freeze-thaw cycles. The proper sealer can avoid further cracking, flaking, and scaling. All you need is a brush, roller, or household broom to apply it. Your concrete can look like new for much longer.

worker cleaning driveway with gasoline high pressure

3. Repair Any Damage

Damage to concrete leaves it highly vulnerable to additional deterioration. Sometimes minor damage can be repaired with items from home improvement stores. Resurfacing compounds can be used for small cracks, but make sure the surface is thoroughly cleaned first. You’ll need a high-pressure washer and duct tape/weather-stripping to protect the concrete joints.

Larger cracks require additional steps. Widen the break with a chisel and hammer (by at least ¼ inch) and remove deteriorating concrete or fragments. Brush away any loose material. If there are cracks more than ½ inch deep, insert a backer rod, and use a caulking gun to apply a sealant.

However, repairing damaged concrete can be tricky. If you don’t have experience in this area, Cross Construction Services can help with your Houston concrete patio repair. Our experienced technicians apply the most appropriate polyurethane sealants and polymer-based cement resurfacers. In addition to using top-quality compounds, we can address stained, cracked, or crumbled concrete, even if retaining walls, expansion joints, drainage, plumbing, or hand railings seem to be complicating matters.

concrete cracks and gaps

4. Seasonal Preparation

In addition to power washing concrete every couple of months, it’s essential to ensure your concrete patio is ready for the challenges each season brings. Here are some ways to provide seasonal protection:

  • Apply a concrete patio sealer at least once a year (less frequently used surfaces can go two or three years between sealing). Otherwise, the permeability of a concrete surface will leave your patio vulnerable to water entry, ice, and erosion due to salt. Reapply the sealer whenever the sheen starts to disappear, or the surface color starts to fade.
  • Clean the gutters and downspouts to ensure water is properly draining from your roof. Blockages can cause overflows and damage that put your concrete surfaces at risk. Also, point gutters/downspouts away from masonry to prevent water from over-saturating the pavement and causing excess wear. For maximum protection, relocate your downspouts entirely or install underground drainage.
  • Stock up on non-chemical deicers. While ice can do plenty of damage, ice-melting chemicals not only break down the sealer but also the concrete material below. The damage may first appear as small divots on the surface, but it will get worse over time. Aside from safer deicers, you can also use sand. Another added means of protection is to lay rugs (on covered patios), which can protect the concrete from stains and damage from furniture.
Modern Patio Cover Install and Design

5. Install a Patio Covering

Patio covers provide a roof to protect concrete. While some covers have an open lattice design for partial shade, a solid patio covering entirely blocks rain, snow, and other outside elements. At the same time, it can provide full shade. It can be sized to cover every square foot of the patio and the furniture, equipment, or dining space it contains. The cover can also protect televisions, sound systems, and other entertainment-related equipment.

With a patio covering, you can also add extra features such as retractable shades, sliding doors, and, for additional comfort and cooling, ceiling fans. You can even extend the ductwork from your home HVAC system to provide heating and cooling on your patio. At Cross Construction Services, our team can also add sunscreens, gutters, plastic composite/glass enclosures, and other functional elements, along with insulating materials such as aluminum or polycarbonate.

Some patio covers are designed to match the exterior façade of the house, right down to the shingles. The choices enable homeowners to match their patio cover with a larger design scheme. For professional assistance designing and building a concrete patio in Houston, TX, and suitable protection that can extend its life, contact Cross Construction Services at 713-254-1703 for a free estimate today!

Ways to Accessorize a Patio

Many homeowners underutilize their patios. The truth is, even if you have a small patio, you can accessorize it to add comfort and function. From adding patio covers to elements of nature, to cooking areas and places to lounge, you can accessorize your patio to make it your own personal retreat. Enclosing your patio can let you, your family, and guests enjoy outdoor living with all the amenities you enjoy indoors—but, first, here are some great ways to spruce up your outdoor area.

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Seven Benefits of Adding an Enclosed Sunroom onto Your Home

Do you have a patio that is exposed all day long to direct sunlight? Enjoying your patio is then not much fun, especially during the hot Texas summers! Even during the fall, winter, and spring months, the weather can still get rather hot and humid. Not to mention, there are pests of all sorts that can make spending time outdoors even less fun and exciting.

If you have a patio on your home but rarely use it for these or other reasons, you should consider this trendy patio design idea: Convert the patio into an enclosed sunroom! An enclosed patio not only makes it possible for you to fully utilize the entire space of your home by gaining additional living space but also to enjoy the outdoors without worrying about the weather or pests.

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Concrete Driveways: More Durable and Economical Than Asphalt

So, you are in need of a new driveway in Houston because your current one is worn out. One of the most important things you will need to consider is what material you want to use for your new driveway. Most homeowners choose between asphalt and concrete.

While some homeowners do choose asphalt, concrete is becoming a more popular option for several reasons. From being an eco-friendly choice to long-term savings, concrete can be the perfect choice for the new driveway for your Houston home.

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