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


Paving The Way Forward With Recycled Plastic

From India to Indiana, from Cumbria, England to Corpus Christi, Texas, everyone agrees the amount of free-floating plastic in the environment is an ongoing problem. With an estimated 5 trillion pieces of plastic adrift on the surface of the ocean alone and uncountable more tons of the material in landfills and vacant lots all over the world, plastic both makes our current standard of living possible and poses one of its most dire threats.

At Calvac Paving, we make a point of keeping current on the latest breakthroughs and experiments in building and paving technologies, and new processes for repurposing plastic as a paving material is very much in our wheelhouse. Several different processes are in the testing stage, including using plastic to coat paving aggregates and reduce the amount of bitumen necessary for traditional asphalt; adding pellets of recycled plastic as part or all of the aggregate portion of the asphalt; and a Lego-like process of building roads from paving blocks of recycled plastic.

Apart from the obvious advantages of reducing the environmental impact of discarded free-range plastic, the primary benefit of utilizing plastic-impregnated asphalt is twofold. First, using plastic seems to increase the tensile strength of asphalt significantly, up to 60% in certain mixes.

Second, by reducing the amount of bitumen, or tar, used as the binding agent in most industrial asphalt mixes, it may also cut the cost of paving by up to 15%. The higher tensile strength potentially increases the size and mass of traffic which can use these roadways, meaning it may be possible to move more freight and larger vehicles in areas where existing paving and statutes would simply not permit them. In turn, this could substantially reduce transportation costs and thus the costs of everything from steel to gasoline to milk.

In addition, plastic-impregnated asphalt may lend itself more readily to hybridization with innovations such as the self-charging roads which we’ve discussed recently. As the costs of developing and deploying these technologies shrink, the likelihood of incorporating multiple technologies into a single roadway increase at a similar rate.

Almost as interesting as what plastic asphalt can do is the story of the various ways in which its applications came to be. In India, a chemistry professor, annoyed with the potholes of his city, remembered seeing people in Mumbai patching similar potholes by filling them with empty plastic bottles



and then heating them to a liquid state. In Scotland, an engineer built on the India protocol by using pellets of recycled plastic, aggregate and a very small amount of bituminous binder to create a roadway surface which causes less wear on tires. Meanwhile, a company in the Netherlands backing the block paving strategy was inspired by the idea that using interlocking blocks would allow for easier infrastructure placement and damaged section replacement.

By reducing the amount of “trash” plastic in the open environment and repurposing it in new ways, these innovators are also challenging accepted notions of what is possible in large-scale construction. These changes in turn may serve to make not only the final product of construction initiatives, but the processes and techniques by which they are created, more efficient, effective and environmentally friendly.

Calvac Paving takes our role in environmental sustainability and finding better ways to accomplish the tasks we undertake more effectively and safely very seriously. It is the entire reason we keep such a close eye on how construction technology is changing and evolving. When and where possible, we make it a point to adopt and implement these changes ourselves, because while we know the “tried and true” methods have survived and been used as long as they have for very good reasons, we also understand there’s almost always a better way to do just about anything if you’re willing to look hard enough for it.

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We at Calvac Paving believe we can best serve the communities we live and work in by emphasizing the fastest, safest and most c
ost-effective means available to do our jobs, while striving to reduce the impact our industry can have on the global as well as local environment. It’s all part of Calvac Paving’s commitment to not just doing the job, but doing it right. We do it for our clients/stakeholders, for our community and for a better, cleaner, healthier world. To learn more about Calvac’s commitment to the environment, or to put the four decades of experience we bring to every project to work for your job, please contact us at (408) 225-7700  or https://www.calvacpaving.com/contact-us/


Bay Area Asphalt Contractor Completes Latest Project

IMG_7684At 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.

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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.  

IMG_7708Calvac 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!

 

 

Calvac Paving


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

 


How Many Parking Spots Will I Need For My Strip Mall?

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.

How many parking spots do I need?

 

 

At Calvac Paving, we have CASp (Certified Access Specialists) available. Our CASp specialists serve the San Jose area as well as the greater Bay Area.


Calvac Paving to Exhibit at CACM’s Northern CA Law Seminar & Expo January 24-25

Calvac Paving, a Bay Area asphalt and concrete maintenance company, is attending at CACM’s (California Association of Community Managers) Northern CA Law Seminar & Expo.

This event will be held January 24th and 25th at the  Santa Clara Convention Center. According to a Calvac Paving spokesperson, the event is “California’s premier event for the community management industry!”

The Calvac Paving team will be exhibiting at Booth #1021 in the Paradise Found Exhibit Hall. Also, they are Welcome Reception Drink Ticket Sponsors, to be held on Thursday January 24th from 4:30 pm to 6:30 pm. The reception will include appetizers, a no-host bar and informal networking.

Beyond the exhibit, the event will enable many in California’s management industry to learn and grow professionally. CACM notes, “Let’s face it, the demands and expectations community managers face have never been greater. Do you have the knowledge, expertise and tools you need to meet and exceed those expectations and move your career forward? At this year’s Law Seminar & Expo, we’re bringing California’s best and brightest to help you get there.”

“We hope that all attendees can stop by our booth at the exhibit,” said a Calvac Paving spokesperson. “With over 40 years of experience in the industry, we are looking forward to sharing our expertise and meeting new clients!”

About Calvac Paving:
Calvac Paving is a full-service asphalt and concrete maintenance company that has been serving the greater Bay Area since 1974.

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


Calvac Paving And San Harbour South HOA : A New Parking Lot Case Study

 

Calvac Paving recently undertook a paving rehabilitation project for the San Harbour South HOA  association located at 906 Beach Park Boulevard in Foster City, California. The existing pavement was over 45 years old and was starting to exhibit severe cracking and base failures.

Calvac Paving setting up Primary Client Concerns

The primary client concerns included:

  • Continuous access during the milling, repaving and striping operations

  • Cost

  • Schedule and time management

  • Quality surface at the project’s end

Proposed SolutionIMG_1971

After reviewing the jobsite in person, we came up with a range of possible solutions that would meet the client’s needs.

Calvac PavingDue to sub-grade issues. We proposed milling the existing pavement down 2” from the existing surface and laying approximately 2,500 tons of ½” aggregate hot mix, in addition to the replacement of 1,500 linear feet or 90 cubic yards of concrete valley gutter. Our recommendations and proposed fix were accepted by Calvac’s client and HOA Board. The job was undertaken in phases as to not disrupt the community at one time.

Final ResultsFinished Project Piece

The end result of the San Harbour South HOA project looked fantastic! The project went off without any difficulty and was completed within the stated schedule and budget.

Calvac Paving is proud to have served the Bay Area for over 45 years with a wide range of paving, concrete and ADA access planning and implementation solutions. Why gamble with the outcome of your project? Make sure your contractor can get it done right the first time, every time. To learn more about how Calvac Paving can help service your construction job or to obtain a quote for services, please call us at 408-225-7700.

 

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


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!


Bay Area Asphalt & Concrete

Since 1974, Calvac Paving has taken great pride in serving the Bay Area Asphalt & Concrete construction needs.

Consistently ensuring the highest possible quality and best results for clients means keeping pace with the latest innovations in paving technology and techniques. Calvac Paving’s dedicated and knowledgeable paving professionals have amassed considerable experience in everything from new construction to refurbishment and repair of old, worn paving such as sidewalks, parking lots, roadways and more. While many paving companies focus solely on one kind of paving, Calvac Paving can boast extensive experience with asphalt, concrete and earthwork, from initial  grading to final striping. Among the services Calvac Paving offers to the public are:

Calvac Paving offers the following Services

  • New Construction
  • Grading
  • Concrete Placement
  • Asphalt Placement & Compaction
  • Striping
  • Asphalt Seal Coating
  • Pulverizing In Place
  • ADA upgrades to existing structures
  • Crack Sealing & Repair
  • Petromat Overlays
  • Parking Lots
  • Asphalt Repairs 


In addition to these services, Calvac Paving takes its obligations to the environment we all share very seriously. We use the latest green and eco-friendly policies and practices at every stage of construction from the project’s start to the final cleanup and disposal of waste products at the end.  Most business owners would agree that taking steps to be a greener business is a win-win for everyone.

“Green” Paving?

While this phrase may sound oxymoronic, asphalt pavement has consistently been reported as the most frequently recycled material in the nation since 1993. Continuous improvements in recycling technology and paving practices and techniques that permit for more adaptive uses of existing paving materials have fueled this recycling boom with regards to asphalt and, to a lesser degree, concrete. Purely virgin asphalt, also known as “hot-mix,” is relatively rare today because of the numerous advantages of recycling asphalt in place. However, many old-school pavers often still refer to “warm-mix,” discussed below, as “hot-mix” regardless of this designation’s true accuracy.

Most asphalt you see on the road today consists of rocks, also called aggregates, sand, binder material and additives such as shredded rubber tires, pig manure and metal slag, to name a few. These additives are re-purposed and treated in such a way as to make them a cohesive part of the overall mix and increase the mix’s performance. This transforms relatively useless or even outright hazardous materials into reasonably safe and effective filler materials for asphalt mixes. However, the most common fillers are recycled asphalt paving and asphalt shingles. Using these materials in “warm-mix” asphalt paving sharply decreases the amount of virgin oil binder needed to create a safe driving surface with proper internal cohesion and compactive properties.

According to the National Asphalt Paving Association, in the 2013 construction season alone nearly 68 million tons of recycled asphalt and almost 2 million tons of asphalt shingles were used as recyclables, at a savings to taxpayers of around $2 billion. The use of recyclables has increased 21% since 2009 and represents over 99% of all in situ, or existing, asphalt paving being recycled and re-purposed instead of ending up in landfills.

Calvac Paving is proud to be part of an industry that is able to recycle and reuse apparent waste materials so efficiently and effectively. Calvac Paving takes a deep interest in ongoing advances in procedures and techniques that allow for new ways to re-purpose existing pavement, whether it is asphalt, concrete or something else.

 The Future Of Asphalt & Concrete

The interest in new advances is not limited to asphalt, because Calvac Paving is dedicated to finding more efficient and ecologically sound ways of achieving the same overall goals. One development that Calvac Paving is watching with great interest is so-called “bio-concrete.” In this type of concrete, a regular concrete mix is impregnated with tiny plastic capsules containing a type of bacillus bacterium which feeds on calcium lactate and excretes limestone. The capsules dissolve when exposed to water, activating and freeing the dormant bacteria within to begin the healing process. This landmark technology could result in admixtures for other types of paving, increasing the strength, performance and longevity of all kinds of paving and reducing necessary time-of-life repairs dramatically.

As paving technology and techniques evolve, Calvac Paving intends to retain our leadership position in adopting new practices, prioritizing greater safety, security, durability and environmental awareness in every task we undertake. From new builds to maintenance and repair of existing paving projects, Calvac Paving wants to ensure that its products and services stand the test of time, just as we have since 1974. For your next paving project, whether you’re starting from scratch or trying to determine the most efficient and effective way to repair or replace worn, cracked or improperly placed paving materials, Calvac Paving’s experienced personnel can become stakeholders in your properties. We welcome the opportunity to show you why Calvac Paving has been building the Bay Area for over forty years, giving real results that stand the test of time!

Calvac Paving

 

(408)225-7700

(650)694-7944

 (831)375-7944

 

 

 


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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