Posts By: Calvac Paving
At Calvac Paving, we think the history and evolution of paving and construction materials over time is just as interesting and important as using them properly to deliver great, durable results for the projects we work on. For this week’s Maintenance Monday installment, we’re going to take a look at the surprising and fascinating history of asphalt and answer a few questions we get a lot from clients and the general public. You might even learn new facts to stump your friends or help your trivia team crush the competition, courtesy of your friends at Calvac Paving!
When Was Asphalt Invented?
The “active” ingredient in asphalt is tar, also called pitch and technically known as bitumen. It is a naturally occurring petroleum byproduct that is formed from the decomposition of buried plants that were ancient when the dinosaurs rose to ascendancy on the planet. It is often found in pitch lakes and oil sands. It is also created as a byproduct of petroleum distillation, which today is the most popular source of bitumen due to global fossil fuel consumption.
One of the most famous natural sources of bitumen is California’s very own La Brea Tar Pits, which also happens to be one of the most notorious and productive Ice Age fossil concentrations in America. This is because water accumulating and floating on the surface of the pits attracted prehistoric animals to drink from it—trapping them in the hot tar and preserving their remains!
The earliest known references to the use of bitumen as a building material date all the way back to ancient Mesopotamia. Bitumen was used to waterproof temple roofs, ritual baths, and rainwater collection vessels, basically serving as an ancient precursor to silicone caulking. The Phoenicians used pitch to protect the hulls of their ships from the ravages of saltwater, weather, wind, and waves, which in turn helped rank them among the world’s most skilled and feared navies of the day. There is a school of thought that suggests the formula for the legendary “Greek fire,” which could burn on water and was primarily developed as a counteroffensive measure against the Phoenicians and other seafaring foes, may have incorporated bitumen in some way, though this cannot be factually substantiated since the actual process for producing this fearsome weapon has been lost to the ages. In Egypt, bitumen was employed as an adhesive for the funerary wrappings of royalty to protect both the earthly bodies and the treasures bound within the linen bandages which formed the shroud.
To the best of our knowledge, Ancient Babylon has the best claim to fame for the first use of asphalt as a paving material, somewhere around 625BCE.
From Babylon and Carthage, the idea caught on with both the Greeks and the Romans. In fact, the word “asphalt” derives from a Greek word, “asphaltos,” meaning “secure.” The Romans used this new Babylonian technology to create smoother, more efficient roads to move goods, supplies, and, naturally, military forces throughout the Empire.
The first use of asphalt as pavement in modern history appears to date to the 1700s, when an Englishman named John Metcalf began laying roads using asphalt around England. A Scot, Thomas Telforld, took up the idea and brought it to Scotland, where it was later perfected by one John Loudon Macadam. Macadam used a combination of crushed rock and bitumen to create his asphalt roads, giving rise to the names “tarmacadam,” “macadam” and “tarmac,” all names which are still in common use on the Continent, and to a lesser extent in the United States, today.
Asphalt in America
The first recorded asphalt roads in the United States were laid in Newark, New Jersey and on Pennsylvania Avenue in Washington, DC by a Belgian chemist, Edmund DeSmedt, in 1870. This was also the year the first hot mix production operation in the United States began. Curiously, the first patent for asphaltic concrete was not filed until 1871! Another patent in 1900 referenced “bitulithic” concrete, a portmanteau term of “bitumen” and “lithos,” the Greek word for “stone,” which set the foundational template for nearly all asphalt mix designs used in America up to the present day.
As early as 1907, the rise of automobiles as a primary transportation method and the increasing demand for gasoline to fuel them had made man-derived asphalt the most popular source of bitumen. In a magnificent twist of ingenuity and synchronicity, the very thing that made cars run also provided the materials on which they could drive!
Today, asphalt or asphaltic concrete, as it is technically known, is by far the most popular paving material for everything from parking lots to interstate highways. It is also used in roofing materials such as asphalt shingles. Raw hot mix can also be applied to the surface of a roof, creating a light, strong, waterproof surface.
Natural asphalt is rarely used these days, partially because asphalt derived as a byproduct of petroleum production is so plentiful and relatively cheap compared to the expense and effort required to distill asphalt into a usable purified form.
Another reason natural asphalt sources go largely untapped is because many of them, like the La Brea Tar Pits, are protected by local, state, and federal laws for their paleontological and cultural value.
Fossil plants, animals, insects, and human artifacts from Native American tribes in these areas have all been found, making their ongoing conservation and preservation a major point of interest to nature and environmental groups, Native American tribes, and government agencies alike.
Finally, asphalt is one of the most recycled substances on earth. An estimated 89.2 MILLION tons (178.4 billion pounds/81.09 billion kilograms) of asphalt were reclaimed and recycled into new mixes in 2019 in America alone according to the National Asphalt Paving Association. This means that overall, asphalt is very environmentally friendly and is not considered an air pollutant by the EPA, even though the fumes from fresh asphalt can be a little overwhelming if you’re not used to them.
So the next time you’re driving down the highway or pulling into your own driveway, you might take a moment and spare a thought for the fact you’re driving on the results of an idea older than recorded history!
And of course, for all your concrete and asphalt paving needs, click here to contact Calvac Paving and get the job done right the first time, every time!
One question we hear a lot at Calvac Paving, usually from private homeowners and people who don’t work in construction, is what the difference is between cement and concrete. After all, many people call concrete trucks “cement mixers” and refer to the finished product as “cement.” The problem is, this isn’t just inaccurate, but it can cause a lot of unnecessary confusion between contractors, engineers, and the general public. To explain why this matters, let’s start by taking a closer look at how cement, the key ingredient in concrete, is made.
Everything You Need to Know About Cement
Cement is not the only ingredient in modern concrete, but it is the base agent. The most commonly used type of cement is known as Portland cement, because of the end product’s resemblance to an ancient building material found on the island of Portland, off the British coast. This method of creating concrete was first patented by an English stonemason in 1824, meaning modern cement is two hundred years old!
Portland cement is created by burning and then grinding down a mixture of limestone and either shale or clay. This forms a fine, gray powder with hydrophilic properties, meaning it attracts and binds readily to water. When it is mixed with water and allowed to cure, it creates a stonelike surface, similar to plaster of Paris but far stronger and less brittle.
The problem with hydrophilic cement is that it’s both fairly volatile in terms of how readily it reacts with water and can take a long time to cure. Because of this, it has to be carefully stored in a cool, dry place to keep it in powder form until it’s ready to be made into concrete. Admixtures that help reverse the cement’s hydrophilic properties are often added to the matrix during the mixing stage to reduce the cure time and boost its strength, flexibility, and resilience.
How Concrete is Made
Now that we know how Portland cement is made, it’s time to take a look at how concrete is created, which is really quite simple. By adding water, aggregates from fine sand to large crushed rocks, and in many cases chemicals to the Portland cement, you can create a concrete mix that will meet target strength and flexibility profiles, a specified air content range, and even make concrete in different colors!
The quantity and percentage of cement, water, and aggregates of different sizes to be added will depend largely on what the concrete mix is intended for. On a freeway bridge where asphalt paving is not desirable, you will probably want a fairly lightweight, smooth mix. This typically requires more sand and chemicals with a larger quantity of smaller aggregates than an ornamental walkway, which obviously won’t be expected to stand up to the same stresses as a highway.
The various dry materials are loaded onto the concrete truck at a batch plant. Each truck is supplied with a batch ticket, which shows the percentage and weight in pounds of the various dry ingredients and chemicals. Once the dry materials are loaded, the driver will add a specified amount of water. With the water added, the concrete has to be constantly agitated by rotating the drum to keep it from hardening in transit. If the mix cures on the truck, it’s nearly impossible to remove. If you’re a fan of the show Mythbusters, you may remember they did an episode where they tested a myth about using dynamite to clean out a drum full of concrete that had been set up en route to a job site.
Yes, concrete really does get THAT hard!
Concrete on the Jobsite
Once the mixture reaches the placement location, the tickets are often collected by the technicians who sample and test the concrete to ensure compliance with the project parameters. These technicians may be employed by the company supplying the concrete, a private third-party laboratory, or local, state, and federal authorities. About halfway through the load, if required, they will take a sample from the truck for testing.
Some common concrete tests include:
- Slump Test: Too little or too much water means the concrete may not perform to specifications when it hardens. Many companies send their concrete from the batch plant with the minimum water possible added, because it’s far easier to add water to a drier load than it is to get water out of an overly wet one! A slump test is performed by using a steel cone to form the raw concrete into a 12-inch-high cone and then pulling the steel form away. Upon removing the cone form, the concrete cone should fall. By measuring the amount the cone falls, or “slumps,” when the cone form is removed, the technician can determine whether the concrete’s water concrete is within the proper range for the mix design to perform as expected.
- Unit Weight and Air: These tests allow a laboratory to extrapolate from a given sample about whether the mix design as loaded on an individual truck is within the parameters specified for a given project or application. The air test is particularly important and most commonly done on high-traffic roadways which will receive a lot of exposure to the elements and temperature extremes, because too much air in the mix may allow for air bubbles to form, allowing moisture and frost to infiltrate the matrix and over time, break it up.
- Cylinder Tests: When you hear someone talking about “pulling cylinders” on a concrete pour, it’s almost certain they’re talking about this test. The raw concrete is formed into cylinders of a specific size and depth using plastic molds and allowed to cure onsite in a temperature-controlled environment such as a cooler for at least 24 hours. After this, the cylinders are taken back to the lab, “stripped” out of the molds, and placed in a high-humidity environment to cure until it’s time to break them. Commonly, a set of four cylinders is taken from a given load. This includes one to be broken at 7 days, at which point the concrete mix should meet 70% of the intended break strength; 2 to be broken at 28 days when the concrete should have reached 100% of the specified break strength; and one cylinder to be kept on hold in case one of the 28-day breaks fails to meet the specified strength, in which case it will be broken at 56 days or as directed by an engineer. Note: Your project may have different requirements, so be sure to check with the Engineer of Record for the exact testing protocols!
Once these tests and any others the project specifications require are done, the concrete can be certified as meeting the project parameters and construction can continue.
Putting It All Together
Now that you know how cement and concrete are made, you can see they’re not the same thing. It’s easy to understand why some people persist in calling concrete mixers “cement mixers,” even though this isn’t entirely accurate. It’s also obvious why some people stick with calling concrete “cement,” since it’s the Portland cement that cures and makes concrete a durable building and paving material rather than just a jumble of wet rocks and sand.
However, it’s important to understand that when you ask for “cement” and you mean “4500-PSI blue concrete for an exposed-aggregate walkway,” you’re at the minimum going to cause some confusion and brand yourself as an amateur. At the worst, you’ll wind up with a pile of dry Portland cement, which on its own will certainly do you no good when you’re building a roadway or a sidewalk.
But now that you know and understand the difference, you’re far less likely to have that problem—and you’ll sound just like the experts!
Every year, about 6 trillion cigarette butts are produced worldwide, or about 800 discarded butts for every man, woman and child on the planet. Not only are these butts an unsightly and expensive waste disposal problem, but the toxic chemicals which the filters trap and contain leach out over time to poison soil, groundwater, rivers and oceans. Now, a researcher at RMIT in Melbourne, Australia says he may have found a surprising answer to this problem: incorporate cigarette butts into asphalt aggregate!
According to the researcher, by coating the butts with a combination of paraffin wax and bitumen, the black substance also known as “tar” that gives asphalt its distinctive properties, it is possible to trap toxins which used butts contain while repurposing them as a lightweight, flexible asphalt aggregate component. This reduces the overall weight of an asphalt mix design while removing a potential 1.2 million metric tons of waste from the planet’s biosphere.
Another interesting side effect of adding cigarette butts to asphalt is the reduction of heat. Asphaltic concrete has been directly linked to the so-called “urban heat island” effect, caused by vast amounts of asphalt in a relatively small area. Cigarette filters are mostly made from cellulose acetate, a fibrous material which is spun down to look and feel like cotton. This material serves as an insulator which filters out toxins in cigarette smoke while helping prevent burnt fingers for those who simply must light up. These filters reduce thermal conductivity and reduce the thermal density of the mix. When placed as part of a roadway the asphalt containing the filters absorb and diffuse more heat, resulting in a cooler surface temperature and less radiant heat being redirected into the environment.
The final paper on this study states that butts coated with bitumen satisfied requirements for medium- and heavy-traffic mix designs. This would apply to interstates and surface streets with heavy commercial volume. Streets in residential neighborhoods, parking lots not marked for commercial vehicles and similar applications might use paraffin-coated butts. In the study, the research team used 10kg, 15kg and 25kg (about 22, 33 and 55lbs respectively) of encapsulated cigarette butts per cubic meter (1.30795cu.yd) to determine the ideal asphalt mix.
Since cigarette smoking on a global scale isn’t likely to go away anytime soon, finding new ways to deal with this waste is becoming a more pressing problem every day. Estimates claim that the mass of discarded cigarette butts may increase by as much as 50% by 2025 because of the increase in global population. Knowing this, recycling these butts into asphalt and other lightweight construction materials, as the author of the study proposes, may help us all breathe just a little bit easier.
At Calvac Paving, we know we only have one planet, and it’s up to all of us to care for it the best way we know how. There’s no reason that building a solid product and being ecologically responsible should be mutually exclusive, and we’re always on the lookout for new ways to incorporate green ideas into our building design.. We will keep a close eye on this and other “green” developments in construction materials, so we can continue to deliver the most environmentally sound products and processes possible without compromising on quality or durability. It’s all part of our commitment to make the communities we serve, and the world we all share, a safer and healthier place for everyone.
One question we often hear at Calvac Paving is about asphalt cure times. This is a great question because understanding how the asphalt curing process works helps you understand when you can safely stripe, park, walk, and drive on the new asphalt parking lot and what sort of performance you can expect from your asphalt long-term. Let’s take a closer look at how the asphalt installation process works and how this affects the asphalt curing process!
Asphalt Surface Installation
Most asphalt paving companies prefer not to place a fresh asphalt surface if the ambient temperature is outside the range of 50°F-90°F. If it’s too hot, asphalt will not cure quickly enough. Paving when it’s too cold can cause the asphalt crack as it rapidly cools. Weather conditions can make a difference as well. If you watch carefully, you’ll notice paving companies rarely place asphalt in heavy rain. While it is possible to pave asphalt outside these parameters, it requires special preparation and oversight.
The rules for hot asphalt patch, resurfaced asphalt sealcoating and cold patch asphalt placement are a little different, so for purposes of this discussion, we’re going to focus on a clean installation on grade for commercial or residential paving like parking lots or a driveway.
How Long Does Asphalt Take to Cure?
The curing time for asphalt depends on the asphalt mix design, the oil content, the temperature of the mix, the thickness of the paved asphalt layers after compaction, and the temperature and weather conditions when the mix was placed. Generally, you can open new asphalt to public foot and vehicle traffic 48-72 hours after it is placed because this allows time for the asphalt to harden, but you may need to allow a bit more time during hot weather. Asphalt doesn’t fully cure for 6-12 months, so it’s important to keep a close eye on it during this time because it will be less resistant to damage.
The reason we stress the difference between “curing time” and “asphalt drying time,” even though they’re often used interchangeably is that asphalt is designed to be flexible. For it to remain flexible, it has to retain a certain amount of moisture. Water infiltration in paved asphalt driveways, parking lots, roadways, speed bumps, and other asphalt surfaces is the primary factor leading to a blacktop drying out. The water washes away the oil which keeps the asphalt overlay flexible and resilient. You can tell when asphalt dries because you’ll notice cracking, warping, raveling, and loose aggregate appearing on the surface of the matrix, especially sand and other fine aggregates. Fortunately, it takes months to years of asphalt drying time to start noticing signs other than cracking.
What Can I Do to Not Allow My Asphalt to Dry Out?
Good roadway and parking lot maintenance programs can help prevent a lot of problems. Putting down asphalt seal coating on a regular basis, especially when you freshen up your street or parking lot striping, can help prevent more costly asphalt repairs down the line. This is also a great time to do any basin repairs and crack filling, as catching these problems early, when they’re small, can keep your asphalt fresher and more flexible for a lot longer.
Asphalt sealer drying times vary, but 4-8 hours to dry is usually enough for your sealer to ensure it will keep water out. However, the full drying process for the sealer takes around 24 hours, and it’s important to allow your sealcoating to dry completely before line striping for maximum resiliency and effectiveness. As with any other kind of asphalt sealant, you want to allow crack sealer to cure for at least 24 hours in perfect conditions, and add a day for cool, cloudy, or high-humidity conditions just to be on the safe side.
Final Thoughts About How Long It Takes Asphalt to Dry
Of course, the best mix design in the world won’t do you any good if it’s improperly placed, if your striping doesn’t meet the latest ADA criteria or if you don’t take proper care of it. For the best possible results and the greatest confidence in your paving job from breaking ground to the final walkthrough and for years of use beyond, click here to contact Calvac Paving. We’ve been proudly serving the Bay Area since 1972 on residential, commercial, and government projects of all types. Our track record for consistent quality, service, and excellence in every aspect of our operations speaks for itself. Put our experience to work for your paving refurbishment, repair, or new construction needs and see why Calvac Paving is the contractor you need for paving that works the first time, every time!
Calvac Paving’s commitment to service means that we often have projects that present unique challenges. For a medical center in Menlo Park, there were several problems that had to be overcome. First, the base below the asphalt had become unstable, leading to depressions and potholes in the surface. Due to these conditions the existing asphalt had to be removed, the baserock graded and compacted. Second, the existing asphalt had to be off hauled and new pavement placed over the recompacted baserock. Finally, because it is an active office, we had to complete the removal, replacement and striping in a single Saturday.
When we first arrived, the parking area was riddled with potholes and puddles from the destabilized base. The existing striping and stall design of the parking lot was several years out of step with current ADAS and CBC standards for access. We then scheduled the off haul of recycle and import of hotmix asphalt tonnage and we mobilized the equipment and manpower necessary to complete the job, as well as staging the striping crew. Since we had a very tight window and no margin for error, we knew this had to be done efficiently and correctly the first time, with no delays. After blocking off the area so that we could work safely, we began grinding out the existing asphalt using a specialized milling machine. This pulverized the existing asphalt so that we could haul it to a local recycling plant, while exposing the existing baserock surface. Once that was completed, we graded and compacted the baserock so that Calvac Paving could create a stable, uniform surface that would create the necessary drainage and eliminate the puddles. This process, known as “grading,” is key to establishing a surface safe for vehicles and pedestrians while permitting stormwater drainage, which helps prevent subgrade destabilization by not allowing water to collect and seep through the asphalt.
Once the grade had been established and the baserock compacted to comply with industry standards and project specifications, we placed fresh hotmix asphalt in two 2” layers, or “lifts.” Compacting the asphalt in lifts as it was placed, created an end product that is more durable, less prone to cracking, potholing and other problems seen with asphalt paving. Once the second lift was placed, and we fog sealed the surface, we then had to layout and stripe the parking lot up to current ADAS and California building code requirements for correct access to the building and parking areas.
The result was a very smooth and puddle free, pedestrian, parking and driving surface that is far more stable than the previous paving, as well as meeting the latest standards. At the end of the project, we had removed and replaced more than 150 tons of hotmix asphalt in a single day, which was a quick turnaround for this volume of material and the job specific constraints.
Calvac Paving has been serving the Bay Area for over 45 years, from road rehabilitation projects in Los Altos Hills to this medical center parking lot overhaul in Menlo Park, and we have constructed, repaired or remediated thousands of properties. Each project requires a slightly different approach, due to project requirements, schedules, access concerns and other factors. We pride ourselves as the Bay Area’s solution to those supposedly “challenging” jobs, combining our reputation for safety and efficiency with the attitude that there’s no reason to consider a job “challenging” with the right safety, tools, training and equipment.
We also offer an industry-leading three-year warranty on the finished product to our qualifying clients as proof that we stand behind our product and the workmanship that goes into it. We are committed to providing our clients and stakeholders the best and most efficient results in the business, while making sure that the product that we leave behind is one we can look back at with pride. For more information about how Calvac Paving can help with your job, from a major roadway reconstruction to building an ADA-compliant access point to restriping a parking lot, we invite you to call us at:
(408) 225 – 7700
(650) 694 – 7944
(831) 375 – 7944
Some things in life shouldn’t be left to chance, and the surfaces where you, your family and your clients drive and walk on a daily basis are good examples. When you want the best, done right the first time, every time and on time, you want Calvac Paving, and we want to help!
The last 18 months have been rife with uncertainty and riddled with worry for nearly everyone. With businesses closing temporarily or permanently, the Bay Area’s paving situation has never been as dire as it is now. The fact is, if your parking lot, driveway, and other paving problems aren’t corrected early, they’ll get worse and more expensive to fix later. Here are five reasons the best time to maintain your asphalt is NOW!
1. Fluctuating Oil Prices
The price of oil impacts everything, perhaps especially in the construction industry. Asphalt and concrete batching and production processes are uniquely affected by the cost of oil. In July 2020, the cost of asphalt tumbled to a low not seen since March of 2017. One year later, the price has increased by nearly 50%, spurred on by rising oil prices and a concurrent rise in the cost of refining, processing, and batching. With prices going up, now is the best time to lock in current rates for asphalt and concrete before the cost jumps even higher.
2. Curb Appeal
How can you tell the difference between a closed business and a business that’s open and ready to take care of its customers? The truth is your customers can’t, especially if they’re driving by on the street. Cracked, faded, potholed parking lots with worn-out striping are unattractive to the eye and send an unflattering message to potential clientele. By repairing your parking lot, accessways, and other curb and drive installations, you clearly communicate that you’re open for business, ready to get to work and able to assist your customers with all their needs.
Did you know that cracked or potholed asphalt, offset sidewalk slabs, and other defects and damaged portions can be a safety hazard? It’s true! If a customer trips and falls because of poorly cared-for paving, your business may be liable for any injuries they sustain. Such hazards can also impede disability access to your business and maybe an ADA violation with a fine of up to $75,000 for the first infraction and $150,000 for each subsequent violation. When you add up the stiff financial and reputation costs of noncompliance and the potential for injury to your staff, customers, and the general public, having your parking lot and sidewalks repaired looks like a pretty good bargain.
When cracks form in asphalt paving, it allows water to infiltrate the subbase. A small trickle of water isn’t a big deal, though, right? Unfortunately, no. As water seeps into the pavement, it wears and washes away the surrounding material and pools within the matrix, allowing plant seeds to take root and start to grow. During colder weather, it may freeze and expand. These erosive processes accelerate cracking and pothole formation as well as undermining the structural integrity and flexibility of the overlying surface. At a certain point, the paving will be beyond repair and will have to be completely removed and redone to work properly. A well-maintained parking lot will perform and look better for years to come.
5. Increase and Safeguard Your Property Value
Faded, cracked, or faulty paving can be expensive in more ways than you think. It can also drag down the property value, especially if you’re considering selling in the near future. If your paving looks good, it will also perform well for years to come, making the property a better investment for anyone who might end up buying.
All in all, maintaining your asphalt paving is a smart investment with a lot of benefits and virtually no downside over time. Whether you need a simple sealcoat and restriping, a spot patch and repair on a faulty section, or a complete tear-out and rebuild of your asphalt and concrete paving, Calvac Paving is here to help with proven, durable results that give you, your tenants, and their customers the great performance and appearance they expect and deserve. For all your Bay Area paving needs and a job that’s done right the first time, every time, click here to contact Calvac Paving today!
Happy Monday Everyone! In this edition of Maintenance Monday, one of our social media friends sent us this question. I own a strip mall in San Jose, we have 10 retail stores, with 75 parking spots. How do we figure out the correct amount of handicap parking spots to have? The answer is…
Thank you, In this case, 75 stalls. Three would need to be accessible spaces (not handicap), of which one of those would have to be van accessible. One thing to consider is the current count. If this property has 5 existing accessible spaces, it is best to put back those 5. The reasoning is that the standards are the minimum and it is not usually a good idea to decrease accessibility on a property. This is why it is important to plan these layouts with an ADA specialist, you don’t want to create a problem in the future by guessing or overestimating today.
At Calvac Paving, we have ADA Expert(Certified Access Specialists) available. Our ADA Expertspecialists serve the San Jose area as well as the greater Bay Area.
Modern technology and paving practices have revealed faster, more cost-effective solutions to problems that once would have required expensive tear-out and repaving operations. One of the best examples we at Calvac Paving have ever seen was the rehabilitation of the Redwood Shores parking lot we recently undertook. This project mixed new technology with time-tested techniques to deliver a great result for the client, faster and more efficiently than conventional paving methodology.
The parking lot itself was old, cracked and weathered from years of use, but not so bad as to need a complete removal and replacement. Age and oxidation from poorly placed asphalt atop moisture-sensitive base material had caused the asphalt to crack and dry out, reducing its flexibility and its resilience. The parking lot was in need of a major face-lift, and Calvac Paving had the perfect product and the years of specialized talents to make it happen. This was a very unique project in that it perfectly fit the criteria for a very specific application: a Petromat overlay.
Petromat is a non-woven reinforcing fabric that is applied using a liquid asphalt binder known as RS1, which works as a penetrating adhesive and moisture barrier. The Petromat fabric helps to retard the existing cracks from reflecting through the new asphalt surface and gives the finished surface a higher tensile strength, thereby distributes the weight of heavy truck traffic over a greater area. After that, a full two-inch placement of hot ½”fine asphalt is placed with self-propelled paving machines. Once the asphalt has been placed, the compaction equipment follows immediately behind the paving equipment. These very large and heavy smooth drum rollers compact the hot asphalt to a dense, smooth and uniform finish.
Once the compaction process is completed and the hot asphalt has cooled, we then apply a fog seal mixture of 50% SS1 and 50% water. This is designed to help bond the top layer of new asphalt and give it that black shiny “new pavement” look. After the Petromat overlay is 100% completed to our satisfaction, we can proceed with striping and stenciling operations.
Because of the unique considerations and time constraints of the job, Calvac Paving recommended a 2” Petromat overlay over the entire parking lot, measuring approximately 63,500 square feet. This offered the best results for the budget and gave them similar benefits to getting a brand-new parking lot for years to come, without the hassle, expense and lost time of a complete remove and replace. This project also had some very unique parking design restrictions, offering a perfect opportunity for Calvac Paving to design a new layout for the regular and ADA stalls. This redesign included larger stalls, which helped prevent unnecessary dents in car doors, making both the tenants, and owners happy with their new parking lot investment.
Please feel free to drive by and see what a truly professional paving project should look like, and what your commercial parking lot can look like too! From a private roadway rebuild to a complete parking lot rehabilitation and much more, there are very few jobs Calvac Paving cannot do. We’ve been serving the Bay Area for more than 40 years. Now let us serve you! To find out more about Petromat or how we can help with your next project, contact us by email or by phone at:
(408) 225 – 7700
(650) 694 – 7944
(831) 375 – 7944
When you need the best, don’t leave the results to chance. Contact Calvac and have the job done right the first time, every time!
The saying “They don’t build ‘em like they used to” is literal truth in the concrete industry. For decades, modern science has struggled to work out how ancient societies such as the Romans were able to create buildings, monuments and roadways which are still visible and even in use today, when the average lifespan of modern concrete tends to be far more modest. Now, a team of scientists from the University of Utah believes they may have found the surprising answer to this centuries-old mystery.
Modern concrete uses Portland cement as its base, which is a fine powder created from lime, chalk, sandstone, iron and other materials and then combined with aggregates of varying sizes. However, the Romans used a type of cement created from the ash of certain volcanoes. These volcanoes’ emissions contained a rare combination of mineral elements which only occurs naturally in very specific areas with particular geological profiles. What’s most surprising is that the minerals which make Roman cement different from Portland cement appear to react to seawater, which encourages the crystalline structure of the minerals to continue growing. This actually makes the concrete self-healing and impedes cracking, a feat modern science is still trying to replicate.
This discovery of how Roman concrete was made is important because it could lead to greener and more eco-friendly concrete production and paving technologies, as well as structures with higher strength, structural integrity and longevity under adverse conditions than modern concrete allows for. In addition, Roman concrete did not use reinforcing steel such as a wire mesh mat or rebar, both of which Portland cement will corrode and degrade over time. This may lead to significant cost reductions for new construction on structures like bridges, building footings and other applications.
However, the research team warns it’s too early to get too excited about Roman concrete. First, Roman concrete relies on very specific minerals, namely tobermorite and phillipsite, being present in certain quantities. The researchers say the composition of Roman concrete was largely a matter of luck and being in the right place, at the right time, with access to the right materials. Second, we don’t yet know exactly how the Romans made their cement or what the process was for mixing it with aggregate and placing it. This by itself may leave us several years, or even decades, away from being able to use Roman concrete effectively.
Despite these hurdles, the concepts behind Roman concrete and other green discoveries from the ancient world are constantly being studied, evaluated and applied to our modern understanding of how to build things that last. At Calvac Paving, we’ve been serving the Bay Area for over 45 years in the most environmentally friendly, safe and expedient way possible. We’re always on the lookout for new developments, technologies and ideas which will let us do our jobs more effectively, with less impact on the world we all share. To learn more about our commitment to the environment, or how Calvac Paving can help you with your next project, contact us at:
2645 Pacer Ln
San Jose, CA 95111
Sealcoating is an important process in the maintenance of your all too expensive parking lots. We all know that the costs for paving repairs have increased. This makes it all the more important to protect and preserve your asphalt surface. Calvac Paving has been applying sealcoat for over 45 years, longer than most Bay Area Suppliers have been making asphalt based sealcoats. Each successive generation of sealcoats has provided greater protection from premature wear, moisture intrusion and oxidation. Even with these improvements we strongly recommend the addition of latex and sometimes sand to the existing asphalt sealcoats to extend the life expectancy of these applications. It is also vital for you to have your contractor apply two coats of sealcoat to your property. The first coat, with the added sand and latex, is the filler coat and allows placement of a second coat with added latex only or wear coat.
Preparation of the existing asphalt surface is a very important process in sealcoating your parking lot. Calvac Paving will spend the time necessary to clean and prepare your asphalt to assure a durable and attractive product. We will remove all vegetation, and apply herbicide if appropriate. We will use Power blowers, scrapers, wire brushes and brooms to thoroughly clean the existing asphalt.
This preparation may also include Mobile Sweepers, water trucks or buggies and vacuum trucks. We will burn, scrape and carefully clean the oil spots and apply an oil spot sealer with sand. We will mask utility covers and other structures to protect against coverage. We will apply hot rubberized or coldpour emulsion crackfiller as directed.
The consistency of the asphalt sealer is also very important to the durability of your sealcoat project. Calvac Paving will never exceed the manufacturer’s recommendations for dilution. This addition of water is necessary for the application and actually improves the bonding to the existing asphalt surface. We feel the addition of latex and sand to the asphalt sealer extends the life of the sealer, and we include these admixtures in well over 90% of our sealcoat projects. By extendeding the life of your sealcoat surface with added latex, you reduce the number of times you will need to seal coat and stripe your lot as well as impose upon your tenants over the life of the asphalt.
The combination of effective barricading and traffic control with superior craftsmanship and products will provide you with the best result with the least impact upon you and your tenants.