Posts By: Calvac Paving
At Calvac Paving, we love a challenge. When St. Francis Retreat in San Juan Bautista needed an overhaul of their existing roadway, we were pleased to lend our experience and expertise to the task. The retreat is in a secluded rural setting just outside the town proper, which created some specific concerns we needed to be cognizant of during the project.
Working in a rural area, we had to plan our work in such a way as to minimize the impact on the environment and existing flora and fauna, as well as ensure we avoided disruption of the operations and tranquility of the Retreat itself as much as possible. In addition, we had to consider the safety of our personnel and the general public. Finally, the historic nature of the Retreat had to be taken into account and treated with respect.
The roadway is approximately 1 3/4 miles long and required 2,300 tons of hot-mix asphalt. The rehabilitation consisted of pulverizing, regrading and compacting the existing asphalt as additional base material. Then we laid replacement hot-mix in one 3” lift, compacted.
We are pleased to report the renovation operation went very smoothly. The local residents, staff and visitors were very patient with the unavoidable disruption a project of this sort involves. We were able to complete the project ahead of schedule and within budget, without injury or harm to the area or anyone involved in or affected by it. Best of all, the Retreat now has a great-looking, high-performance roadway which can be expected to last for years to come.
Calvac Paving has been serving the Bay Area since 1972. Let us put our craftsmanship and knowledge to work for you on your next project. For quality, safety and efficiency without parallel, we’re proud to be the construction solution for all your paving project needs!
Concrete is not a ductile material-it doesn’t stretch or bend without breaking. That’s both its greatest strength and greatest weakness. Its hardness and high compressive strength is why we use so much of it in construction. But concrete does move-it shrinks, it expands, and different parts of a building move in different ways. This is where joints come into play.
Although many building elements are designed and built with joints, including walls and foundations, we’ll limit this discussion to joints in concrete slabs. Here’s an overview of the types of joints, their function, and tips for locating and installing joints.
Concrete Joint Information
As concrete moves, if it is tied to another structure or even to itself, we get what’s called restraint, which causes tensile forces and invariably leads to cracking. Restraint simply means that the concrete element (whether it’s a slab or a wall or a foundation) is not being allowed to freely shrink as it dries or to expand and contract with temperature changes or to settle a bit into the subgrade. Joints allow one concrete element to move independently of other parts of the building or structure. Joints also let concrete shrink as it dries-preventing what’s called internal restraint. Internal restraint is created when one part of a slab shrinks more than another, or shrinks in a different direction. Think how bad you feel when part of you wants to do one thing and another part wants to do something else! Concrete feels the same way.
If you have a question for Calvac Paving, please contact us at
2645 Pacer Ln
San Jose, CA 95111
Asphalt is a very versatile and durable paving material. Its resilience and flexibility make it an ideal surface for everything from eight-lane superhighways to driveways to parking lots. However, asphalt does require care and maintenance to function at peak performance, and it can fail for a number of reasons. If you see any of these warning signs of failing asphalt, quick action can save you a lot of time, money, and hassle. Here are eight signs your asphalt may be failing—and what you can do to fix them!
Alligatoring is called that because of its appearance: interconnected cracks that look like alligator skin. It is an indication of load-related deterioration which could be caused by a weakened or improperly compacted subbase material, excessive traffic loading, inadequate pavement thickness, or a combination of these factors.
2. Edge Cracks
Edge cracks are found within 1-2 feet of the outer edge of the asphalt surface, running longitudinally, or roughly parallel to the outer edge. These cracks are caused by improper support of the paving surface at the margins.
3. Reflective Cracks
Reflective cracks most typically form in joints or areas of concrete or asphalt paving which have been previously repaired, such as with crack sealing or where a temporary corrective overlay has been placed to relieve stress on deteriorated paving. These cracks form because of continuing movement of the old pavement due to continuing traffic load.
4. Slippage Cracks
Slippage cracks are easily identifiable because of their crescent shape. They occur either due to poorly bonded pavement layers or an asphalt mix design which is insufficient to the demands of the traffic patterns. These cracks appear because of forces applied by turning or braking vehicles, which cause the pavement to move slightly at first but with accelerating damage to the surface the longer the underlying cause goes uncorrected.
5. Rutting and Depressions
Rutting is caused by weakness of the subgrade or base soil layers, instability of an asphalt mix, insufficient pavement thickness, or poor compaction. Rutting is a linear, surface depression of the wheel path caused by deformation or consolidation of any of the pavement layers or subgrade. Depressions, also known as birdbaths, are localized areas of pavement surface failure caused by poor initial construction techniques that undermine the asphalt over time. These may occur on their own or in conjunction with other failure indicators. If left unchecked, depressions can become potholes (see #8).
6. Asphalt Patch Failure
These failures are easy to spot because they’re very localized to the area where a patch was placed, and characterized by unevenness, deflection or stress cracking along the perimeter of the patch. They are caused by either not fully removing the damaged area to be patched, or not allowing a minimum of one extra foot around the perimeter of the patch area to ensure the patch is bonding to an uncompromised surface. The rate of patch deterioration is influenced by materials selection, compaction, and the quality of the surrounding pavement as well as the underlying subbase. While the latter is not typically visible, adding one additional foot around the patch can help patches last longer and function better under load.
Raveling is caused when the aggregate particles in the asphalt cement wear away under traffic forces. This condition suggests either that a poor-quality mixture was used or the asphalt surface has hardened enough to no longer be supple and flexible.
These bowl-shaped holes are caused by localized disintegration of the pavement surface. Potholes are usually the result of another type of distress that has not been properly addressed. Segregation, failed patches and cracks can all lead to a pothole over time. Weak spots and localized areas of improper or insufficient compaction in the subgrade or subbase, or poor asphalt mix designs, can accelerate degradation of the pavement surface and the formation of potholes.
When you notice indications of paving failure, bring in an experienced paving contractor as soon as possible to restore the surface and minimize downtime, expense and the risk of further, more severe failure in the future. Calvac Paving has been proudly serving the Bay Area and beyond for over 45 years, and we’d like to put that experience to work for your next paving repair or new construction project. For more information, or to learn more about how Calvac Paving can deliver the results you need and want, call any of our Bay Area offices or click here to contact us today!
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.
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 40 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
Maintenance Mondays: This project was for a Medical Building. This required the crew from Calvac Paving to work on a Sunday to minimize disruption. The bulk of the drive lanes were damaged to the extent that we had to remove and replace approximately 45% of the drive lanes. The crew completed approximately 260 tons of removal and replaced with 260 tons of hotmix asphalt. All of the removed asphalt was hauled to a recycle plant. Our crews were completed and out of our yard and on their way home by 6:30pm.
Calvac Paving – Top Quality. On Schedule. On Budget.
At Calvac Paving, we know a thing or two about asphalt repair and Golf Courses. So when Poppy Ridge Golf Course called us to bid on a project to rehab an extensive areas of failed asphalt encompassing the road leading to the golf course and the parking area itself, and to reseal and restripe the parking area and drive entrance, we were pleased to submit our expertise and cost for consideration. Soon thereafter, we learned we had been awarded the project at 4280 Greenville Road in Livermore.
To achieve the repair, we provided 4” asphalt repairs and two coats of seal followed by restriping. This required excavating the failed asphalt and recompacting the subgrade beneath the asphalt paving. Then the hot mix asphalt needed to be placed in two 2” layers, or “lifts,” using 3/4” asphalt on the base lift and ½” medium asphalt on the surface lift. Covering 4,000 + square feet of surface area. This ensures strength, flexibility, and density within and between the asphalt layers, while minimizing air voids which can facilitate water infiltration and lead to premature asphalt failure over time.
Once the subgrade and the lifts had been individually compacted, we provided two coats of Reed and Graham’s OverKote, an asphalt emulsion seal for asphalt which incorporates a latex additive. This step gives a smooth, finished appearance to the asphalt, adds surface resiliency and increases water and dust resistance, extending the operational lifespan of the asphalt.
The staff and patrons of the golf course were extremely cooperative and understanding of our schedule and the project went very smoothly. We’re proud to announce that Poppy Ridge Golf Course has already recommended us for similar projects on the strength of our work here, and we’re excited to be able to demonstrate the quality and efficiency of our work once again.
Calvac Paving has been serving the Bay Area since 1972, and we’re proud to bring the same great results to every project we work on. To learn more about how Calvac can help with your project, call us or send us an email and let us put our experience to work for you!
Portland cement is the basic ingredient of concrete. Concrete is formed when portland cement creates a paste with water that binds with sand and rock to harden.
Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients. Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore. These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder that we commonly think of as cement.
The most common way to manufacture portland cement is through a dry method. The first step is to quarry the principal raw materials, mainly limestone, clay, and other materials. After quarrying the rock is crushed. This involves several stages. The first crushing reduces the rock to a maximum size of about 6 inches. The rock then goes to secondary crushers or hammer mills for reduction to about 3 inches or smaller.
The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln. The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as 12 feet in diameter—large enough to accommodate an automobile and longer in many instances than the height of a 40-story building. The large kilns are mounted with the axis inclined slightly from the horizontal.
The finely ground raw material or the slurry is fed into the higher end. At the lower end is a roaring blast of flame, produced by precisely controlled burning of powdered coal, oil, alternative fuels, or gas under forced draft.
As the material moves through the kiln, certain elements are driven off in the form of gases. The remaining elements unite to form a new substance called clinker. Clinker comes out of the kiln as grey balls, about the size of marbles.
Clinker is discharged red-hot from the lower end of the kiln and generally is brought down to handling temperature in various types of coolers. The heated air from the coolers is returned to the kilns, a process that saves fuel and increases burning efficiency.
After the clinker is cooled, cement plants grind it and mix it with small amounts of gypsum and limestone. Cement is so fine that 1 pound of cement contains 150 billion grains. The cement is now ready for transport to ready-mix concrete companies to be used in a variety of construction projects.
Although the dry process is the most modern and popular way to manufacture cement, some kilns in the United States use a wet process. The two processes are essentially alike except in the wet process, the raw materials are ground with water before being fed into the kiln.
Whether it’s a roadway, a driveway or a parking lot, asphalt takes a pounding over the fall and winter months. The cooler temperatures and more frequent rains can take a toll on even the most robust and well-constructed asphalt pavements. To ensure maximum safety and durability for your asphalt and the people who travel and park on it, Calvac Paving presents ten ways to prepare your asphalt for summer!
1. Take a Closer Look.
Asphalt is very durable and resilient, but there are a number of ways it can fail, so it’s a good idea to have a thorough walkthrough at least quarterly. You should check the condition of your asphalt more frequently in cases of unusually heavy or inclement weather, or if you notice indications of a problem like water flowing down the middle of your lot or roadway.
2. Cracked-Up Asphalt isn’t Funny.
Surface cracking often indicates that the subgrade beneath the asphalt is failing, this will also allow water penetration into the subgrade. In these cases, depending upon the severity, the affected problems such as potholes, alligatoring, or area(s) need to be removed and replaced.
3. Paint it Black.
If your asphalt looks gray rather than black, has a pitted look or you notice deep cracks which may allow water to infiltrate to the subbase, it’s time to engage in crack filling and sealcoating, to help preserve and protect the asphalt and retard further damage.
Note: Most unsealed asphalt has a rough and somewhat textured surface, because of the placement methodologies and the type of hot mix used. The larger the aggregate in the mix the stronger the pavement, but you give up the smooth appearance
The solution to this rough surface is twofold. First, an admixture of 2% latex per gallon of raw seal coat is added to both coats of material. secondly, adding one to four pounds of sand to the seal coat on the first coat will add necessary fine aggregate to fill the voids in the asphalt pavement. No sand is added to the second coat. This works to ensure a better looking, longer-wearing surface.
4. Don’t Stand for It!
Standing water can be a symptom of subsurface issues with a section of your asphalt, usually caused by compaction failure in the subbase. Not only can standing water erode the surface as we’ve already discussed, but it can also undermine the integrity of other sections as the water is forced out of the depression and follows the drainage profile of the area in question.
5. Rainbows Belong in the Sky, Not on Your Asphalt!
If you notice iridescent or rainbow-colored patches, these should be cleaned off as soon as possible. Oil and fuel spills can degrade the asphalt’s surface quickly, creating imperfections which over time can become full-fledged failures, reducing your asphalt’s performance and lifespan.
6. Clean it Up.
In addition to the fuel and oil spills mentioned above, it’s always a good idea to keep your asphalt clean and clear of debris such as garbage. Food products, in particular, should be cleaned up quickly, because these tend to have a relatively high acid content, e.g., ketchup, hot sauce, salad dressing, which then lingers on the surface, promoting deterioration of the asphalt. Besides, it just looks nicer!
7. Root it Out.
If you have trip hazards such as uneven areas or raised roots, now is an excellent time to get them corrected. Trip hazards can be an expensive liability and can presage surface failure later depending upon the nature, type, and expression of the hazard. If possible, identifying and removing these hazards early can extend the life of your asphalt and help keep your insurance premiums down as well.
8. Traffic Control is Important.
Older and graying pavements make it significantly more difficult to see the traffic markings. This can lead to potential hazardous situations. Often the markings, arrows, crosswalks, stops and bars can become unrecognizable because of “ghosting”. This is the prior striping bleeding into view and confusing the drivers and pedestrians and leading to potential accidents. This condition is usually timely with the need to seal coat the pavement. Seal coat and restripe will solve this for years to come. This will also allow the property to be brought up to the current Building Code.
9. Time is Not on Your Side.
By the time most people notice a problem with their paving, the damage could be far more extensive than even a detailed site walk can really pinpoint. Frequent examination and correcting areas which show indications of failure as soon as possible after they’re noted can help prevent costly, time-consuming, and unnecessary repairs.
10. Call in the Professionals.
A paving job done poorly can often be worse than no repair at all. That’s why it’s worth your while to bring in pavement professionals with a solid track record of proven results. Calvac Paving has been serving the Bay Area since 1974, and we have the experience, resources and personnel to do the job right the first time, every time. Put our experience and cutting-edge construction technology and methods to work for your project by calling any of our Bay Area locations or clicking here to contact us!
Recycling is important for our ongoing quality of life. It allows us to reclaim and reuse materials which would otherwise go to waste, clogging up landfills and contaminating our oceans. When most people think of recycling, they may think of cans, bottles, paper or even old computers. But surprisingly, the most recycled material in America is literally right under our feet: asphalt!
Unlike many recyclables, which may have limitations on specific types which can be recycled, any asphalt pavement can be 100% recycled. The American Asphalt Association recently released 2016 data which stated about 79 million tons of asphalt was reclaimed and reused in roadway mix designs and other activities, such as reprocessing into a recycled aggregate base course for use beneath the roadways themselves. In addition, nearly 1.8 million tons of waste and byproduct material from other industries were incorporated into asphaltic concrete mix designs during 2016.
We’ve previously discussed the possible use of plastic bottles and even cigarette butts as elements of asphalt designs which are being explored. By reclaiming these materials into asphalt, it increases their recyclability as part of the mix and helps reduce their impact in landfills. The APA says recycling asphalt saves an estimated 14,664 Olympic-sized swimming pools’ worth of landfill space each year. By adding other recyclable and waste materials to asphalt, this impact will only become greater in years to come.
Recycling asphalt isn’t just good for saving landfill space. It also reduces the environmental impact of quarrying and processing the aggregates and bituminous binders used in the asphalt production process.
Asphalt can be recycled in a number of ways. One of the most popular, and the way which reclaims 100% of the asphalt involved, is to pass chunks of asphalt through a special recycling assembly which raises the temperature to 300℉. Once the asphalt has been processed using this method, it can be laid down on roadways using existing paving technologies and techniques. In this form, it is known as Recycled Asphalt Pavement, or RAP.
Another method of asphalt recycling involves crushing asphalt at a hot mix plant and using the resulting RAP as an additive for “virgin” hot mix. This type of recycling allows for over 30% of the final product to consist of recycled asphalt. By comparison, some brands of paper cups may use only 10-25% post-consumer content, highlighting the recyclable nature of asphalt.
A third way which also reclaims 100% asphalt is to crush the asphalt down into gradations suitable for road base. Rutgers University conducted a study in which RAP was compared to conventional aggregate subbase for use in roadways. The study showed the RAP had more elasticity and stiffness (are you sure they said this, seems contradictory) than the aggregate subbase when the two materials were laid using identical placement methodology. This means RAP is actually stronger, more resilient and better for the environment than regular aggregate road base, while delivering comparable performance as a base material.
If the environmental benefits aren’t impressive enough, consider the potential savings for recycling. That’s right, recycling asphalt costs less than new paving! One estimate places potential savings at a national average of around 55%, or between 30-80%, over virgin hot mix.
It’s up to all of us to do our part to make our world a better, cleaner and healthier place, from the global level to our own homes. At Calvac Paving, we are always on the lookout for ways to perform our work more efficiently and cost-effectively while also remaining environmentally responsible. This means keeping a close watch on new technologies, methods and California State standards which would allow us to deliver comparable or superior results with less environmental impact and greater ROI for our clients. To learn more about Calvac Paving’s commitment to the environment, or to put the four decades of experience we’ve accrued to work for you, please contact us at (408) 225-7700 or www.calvacpaving.com