Topic: Blog

The Lost Art Of Concrete

Cement Contractors

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:

Calvac Paving
2645 Pacer Ln
San Jose, CA 95111
(408) 837-9021


Maintenance Mondays – Drive Lanes Removed & Replaced

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.

 


Bay Area Golf Course Asphalt Repair

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!


Maintenance Monday – How Portland Cement is Made

Cement Plant For Calvac Pavings Blog

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.

Old cement dispenser company

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.

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Maintenance Monday: 10 Ways to Prepare Your Asphalt for Summer

Calvac Paving Bay Area Asphalt and Concrete Contractor

 

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!


Asphalt: The Most Recycled Material In America!

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

 


Maintenance Monday: Don’t Let Poor Drainage Take Your Parking Lot Down The Drain!

 

With the wetter, cooler conditions of fall upon us and winter in full swing, it’s a good time to check your parking lot and other asphalt applications for signs of poor drainage and damage. It’s much easier and less expensive to catch a problem early and correct it than it is to wait until that small cracked area spreads to half the lot. With this in mind, here are four signs you should look for to check if your parking lot drainage is working as it should.

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  1. Rocks or sand in unusual places

If, after a heavy rain, you notice rocks or sand in low-lying areas, this may be an early warning sign that something’s wrong with your drainage. The water from the rain may actually be eating away at the asphalt and flushing away the solid particles of sand and rock aggregate that make up asphalt. To make sure it’s not runoff from the street or areas higher up, look for consistent ripples or waves in the deposits which are larger at the higher end and taper off toward the lower side of your lot. If you see this, your lot is probably okay, unless you see large areas where the sediment and rocks have gathered. This indicates possible low spots which could cause problems later.

 

  1. Pools of water or flow down the middle of the lot

Most asphalt parking lots today are designed along a slight but apparent slope to facilitate runoff. Likewise, they are usually built with an engineered high point called a “crown,” which is intended to direct water away from the middle of the lot and down toward the drain points. Pooling and water flowing directly down the middle of the lot suggests the crown has been compromised or a possible issue with the subgrade, which will need to be addressed before the asphalt begins to buckle.

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  1. Cracking

If you start to see cracks developing, especially in areas where you also see heavy water flow and/or residue such as described above, this is a sign the asphalt is beginning to fail because the water is breaking down the bitumen binder. This may also be a sign of traffic outside the asphalt’s design tolerances being present, such as large amounts of heavy trucks or construction equipment. In either case, once cracking begins, water can infiltrate the asphalt surface and accelerate the rate of failure, making repairing it a priority before it gets out of control.

 

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  1. Are your drain inlets working as they should?

Periodically, it’s a good idea to check your streetside and in-lot drainage inlets to ensure they’re clear of obstructions and debris which may prevent them from working as expected. In many cases, asphalt failure can be traced back to a blocked drain inlet which hasn’t been corrected. Regular property walkthroughs can help you spot problems like this before they become severe enough to warrant repair or rehab of your parking lot, and keep it working the way you expect it to for years to come.

For more information about drainage or to speak with Calvac Paving about your parking lot or other asphalt and concrete construction needs, click here to contact us!


Calvac Paving Celebrates Over 45 Years in Business

Calvac Paving, a Bay Area paving and concrete company, is pleased to announce that they are celebrating over four decades in business. Since the day they first opened for business in 1974, Calvac Paving has strived to offer a wide variety of services, including concrete hardscapes, asphalt repair, interlocking pavers, crack filling, seal coating, and many others.

Over the past 45-plus years, Calvac Paving has grown to become one of the largest Bay Area paving and asphalt contractors. From business owners that need new concrete sidewalks and ADA ramps to schools that have old and cracked asphalt parking lots that are in desperate need of repair, the friendly and experienced team at Calvac Paving is ready and able to help.

In addition to offering top-notch service, Calvac Paving’s website is exceptionally user-friendly, providing visitors with in-depth explanations of the various services they offer. The educational articles not only describe what each service entails, but when it is typically needed. This can help business owners, commercial property managers, homeowners association managers and many other clients to educate themselves and their clients about what work is needed at their properties.

For example, the article about asphalt repair explains that interconnecting cracks called “alligatoring” are typically found in high traffic areas or near dumpster enclosures.

“In the areas of the pavement surface where failure is showing (areas of ‘alligatoring’) we may propose removal of the failed asphalt and replacement with a thicker cross-section of newly placed and compacted asphalt,” the article noted, adding that Calvac Paving will mill, saw cut or jackhammer the perimeter of the failed areas.

“It is recommended that the new ‘patch’ be placed at a minimum thickness of 1-1/2 times the original asphalt depth to bridge any inherent weakness in the base material in that area.”

Anybody who would like to learn more about Calvac Paving is welcome to visit the user-friendly website or Facebook Page at any time; there, they can read more about the high quality services they offer.

About Calvac Paving:

Calvac Paving Inc. is a full service asphalt and concrete maintenance company that has been serving the greater Bay Area since 1974. For more information, please visit http://www.calvacpaving.com


Maintenance Monday – Joints In Concrete Slabs

calvac paving discusses joints in concrete slabs

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

Calvac Paving discusses Concrete Joint Information

Different joints in concrete slabs all have the same bottom-line purpose of preventing cracks

 

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

Calvac Paving
2645 Pacer Ln
San Jose, CA 95111
408-225-7700

sales@calvacpaving.com

 


Calvac Paving To Exhibit At The Northern California Law Seminar & Expo – 2020

CACM IS A Trade Show Calvac Paving Attending

Calvac Paving, a Bay Area Asphalt and Concrete Maintenance company is proud to announce that they will be exhibitors and a sponsor at the California Association of Community Manager’s (CACM) Northern California Law Seminar and Expo which will be held at the Santa Clara Convention Center on February 6th and 7th.

To learn more about CACM’s Northern CA Law Seminar & Expo, please visit :https://cacm.org/events/northern-california-law-seminar-2/

The Calvac Paving team will be exhibiting at Booth #1014 on both Thursday and Friday and will also be a Bar Sponsor for the Vision Awards Banquet taking place on Thursday evening. The Vision Awards will include both a Nominee VIP reception and a Champagne reception.

Representatives from Calvac Paving are really looking forward to participating in the event as well as networking during the Vision Awards banquet. A Calvac company spokesperson added, “We have been in the Asphalt and Concrete maintenance business for over four decades, and we thoroughly enjoy having the opportunity to spend time with many of our current clients as well as meet new clients. We hope that everyone will take the time to visit our booth at the Expo as this is also a great opportunity to share knowledge and answer questions in a casual setting.”

About Calvac Paving:
Calvac Paving is a full-service asphalt and concrete maintenance company that has been serving the greater Bay Area since 1974. For more information, please visit https://www.calvacpaving.com/

Calvac Paving
2645 Pacer Lane
San Jose, Ca 95111
408-225-7700

 

Event Information

Northern California Law Seminar & Expo

February 6-7, 2020

Santa Clara Convention Center Hyatt Regency

5101 Great America Parkway Santa Clara, CA 95054

This two-day seminar offers up-to-the-minute legislative information from California legal experts.