Topic: Blog

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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Bay Area Golf Course Asphalt Repair

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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!


Calvac Paving Continues To Maintain A High Safety Work Record

Calvac Paving

In 2015, we reported Calvac Paving has maintained a high degree of safety, as measured by reduction adjustment to our worker’s compensation insurance premiums. These numbers are released annually, which means we just received the latest figures on our performance. The 2018 California Experience Modification ratings for workers’ compensation insurance have now been released, and once again Calvac Paving is proud to be an industry leader in workplace safety! 

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Calvac Paving’s rating of 76 is well below the industry standard and means that we pay nearly 25% less than what many of our competitors pay for identical workers’ compensation coverage. This means we have had more than 25% fewer incidents and lost working hours than industry actuaries would anticipate for our line of work. Obviously, this is better for our employees and the company as a whole, because it means our training programs and safety protocols are working, and of course, the financial benefits are welcome as well. However, this means a lot more than just a bump in the bottom line to us at Calvac Paving. 

 

An Ex-Mod score of 100 is considered “average,” while an Ex-Mod of 125 would be “high-risk.” Employers with an Ex-Mod of 100 pay the full premium for their worker’s compensation insurance, while a high-risk employer would pay the full premium plus 25%. This metric means our employees are more likely to practice sound safety on the jobsite, while in transit and at the yard, increasing the odds they will all get home to their loved ones in the same condition they left for work. This, in turn, allows clients to accept our job bids with confidence that they will receive consistently excellent work, produced with safety uppermost in mind at all times.

 

 

Calvac’s safety program includes:

  • Up-to-date training on the latest OSHA and DOSH policies, procedures and protocols
  • First aid training including CPR
  • Hazard identification and mitigation
  • Workplace and job site safety and loss prevention
  • IIPP and Early Return to Work programs which allow injured employees to return to work on modified duty while remaining in compliance with healthcare provider recommendations and directives

Our insurance brokers have stated in the past that Calvac’s safety initiatives have been so successful, we are setting the standard for how safety training and associated loss prevention ought to be carried out. As we take a great deal of pride in being the benchmark for excellence in every facet of our operations, this is always welcome feedback.

The principals and management of Calvac Paving are very proud to once more be able to prove we are among the best in the construction industry at what we do. Our emphasis on proactive safety training and implementation means our employees have more productive days with a lower risk of injury, allowing them to perform at their best at work and in their personal lives. We are also pleased that our clients get to reap the benefits of our training in terms of increased production and reasonable budgets, with less potential for damaging incidents.

Construction is not an easy field in which to balance safety with productivity. However, we at Calvac are proud to show it’s not just possible; for us, it’s just the way we do our jobs, every time, every day. We look forward to continuing to prove our commitment to safety and a task done well for many years to come, working to keep our employees, clients and the general public safe as we go.

 

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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

 


Los Altos New Private Road Project

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Calvac Paving was proud to be able to serve the city of Los Altos, California by replacing a  common private road within the community. The roadway needed repair for durability, safety and aesthetic reasons, giving Calvac Paving the opportunity to once again demonstrate the quality and attention to detail of our work.

This project required some delicate handling because, as a private road in a residential area, Calvac Paving had to be mindful of residents’ access needs as well as the possibility of fires or other emergencies. It also necessitated using a special process that allowed for minimum road closure time and maximum performance. We created a short video to show the highlights of the paving process, from top to bottom.

The process Calvac Paving decided to use was a “petromat” overlay on top of the existing roadway. To do this, the failed areas were prepatched using full depth hot mix asphalt. Once this was done, the existing utility boxes in the roadway were raised up, so as to secure them against further failures in the subgrade or roadway itself. An asphalt binder and paving fabric were installed next, allowing the existing road surface to bond properly to the hotmix upon placement. A 2” lift of hotmix was placed using a self-propelled paver, and then the lift was compacted to produce a smooth, level road surface.

The finished product is much nicer-looking, offers more flexibility and durability, and didn’t require as much disruption of local traffic patterns as more traditional repair and rehabilitation projects. Calvac Paving specializes in these kinds of jobs, where tight traffic constraints and the need for access make conventional processes difficult or impossible. In this particular case, we left the property owners with a smoother, more aesthetically pleasing, better-driving roadway.

Calvac Paving has been serving the Bay Area since 1974, providing the highest-quality paving, concrete and earthwork solutions for residential, commercial, transportation and public applications. From annual budgeted concrete repairs, asphalt paving and seal coat to a complete new roadway build and striping services, Calvac Paving has the equipment, knowledge and experience to deliver excellent quality at competitive prices. We approach every job with a can-do attitude and consider carefully how to proceed to obtain the best balance of cost effectiveness, performance and safety.

 

Because our President, Jim Adam, carries CASp certification, Calvac Paving is also an ADA-certified company. This means we are continuously keeping abreast of new developments and adaptations to ADA regulatory requirements and standards. Carrying this prestigious and important certification allows us to ensure every project we undertake is in full compliance with ADA Standards as well as the California Building Code, which in some cases are even more stringent.

In addition to our certifications and awards, Calvac Paving offers a three-year warranty to qualifying customers, three times the industry standard. We stand behind every job we do with strict quality and performance standards, because we want our clients to have peace of mind that the work they get from Calvac Paving will be the best anyone, anywhere can deliver. We hold our work to the highest possible standards for materials, workmanship and durability, Calvac Paving can take pride in giving our clients/Stakeholders a finished product they can trust.

Calvac Paving is proud to have served the Bay Area as long as we have, and we will continue to do so in 2016 and beyond. Whether we’re fixing a private roadway in Los Altos or working on a major airport runway renovation, striping a parking lot or building an access ramp to the exacting tolerances of ADAS and CBC requirements, we are passionate about our work and proud of the final result. To learn more about how Calvac Paving can help you with your next construction project, we invite you to call our offices at the following numbers:

(408) 225 – 7700

(650) 694 – 7944

(831) 375 – 7944

 

You can also contact us by clicking here if you’d prefer to email. For top quality, on-schedule and on-budget, don’t gamble with the results. Call Calvac Paving and get the best right from the start.


Asphalt Crack Repair

Asphalt Repair

One of the processes that paving contractors can perform in these conditions of rain and clear skies is crackfilling. It takes just a day of good weather to allow us to come in and prepare the cracks with the installation of the crackfiller the following day if necessary. Here is some information concerning this service.

CONDITION:

Linear cracking in your asphalt surface. Aged and oxidized asphalt that has intermittent cracking. These cracks are typically wide spread throughout the property and not concentrated in one area nor interlocking.
If there are alligatored areas (interconnecting cracks) then these areas should be repaired rather than crackfilled. These problems are exacerbated by the intrusion of water which will penetrate to the subgrade and accelerate cracking and base failure caused by shrink/swell of the subgrade.

Latest Paving Job Calvac Paving

CAUSE:

Causes of this linear cracking could be a less than satisfactory base course on top of a moisture sensitive subgrade causing swell and shrinkage in that subgrade. This movement reflects through the base course and the up through asphalt surface. The infiltration of moisture through this cracked and oxidized (dried out) asphalt accelerates the damage.
Additional causes would be ground slippage, expansion and contraction due to heat and cold cycles, shrink/swell of the subgrade, the advanced age and oxidization of the asphalt surface.

CORRECTION:

Cracks that are 1/4” -3/8” can be filled with a cold pour asphalt emulsion crackfiller. Cracks that are 3/8” – 3/4” will require the use of a hot rubberized crackfiller. Cracks larger than 3/4” should be corrected with hotmix asphalt, by filling the cracks with hotmix asphalt and covering with hot pour crackfiller and better yet is to follow up with a Petromat overlay of the area.
With either application the cracks will have the existing vegetation removed and then the crack will be blown out with high pressure air and high heat. If necessary we can apply a spray sterilant to the existing vegetation prior to removal.
If we apply cold pour crackfiller, then that material is poured into the crack to bridge the opening and create a flexible filler that is then struck with a specialized squeegee to force the material deeper into the crack and to localize the coverage of the material into a thin strip at each side of the crack.
If the cracks require hot rubberized crackfiller, then that material is heated to 350°+ and the material is forced into the crack and struck flush with the surface.

If your property is in need of a asphalt/concrete repair, Calvac Paving is standing by to assist!

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


The Greenest Mile: How Charging Roads May Make Electric Cars More Efficient Than Ever

Electric Car in Charging Station.

At Calvac Paving, we support technologies and construction methodologies that offer a more environmentally sound and sustainable way of creating the things we as human beings have come to rely on. From asphaltic concrete recycling to innovations such as self-healing concrete, we are always on the lookout for trends and techniques that change how we operate for a greener, healthier planet. This is why we are so excited about the possibility of roads that actually recharge electric cars as they drive! These specially designed roadways will reduce pollution, increase the performance and range of electric cars to unheard-of levels, and reduce or entirely eliminate the need for charging stations.

electric charging road ways

In the UK, this seeming science fiction is becoming science fact, as the government moves to experiment with charging roads. Operating on the same principle as a wireless phone charger, the roads will charge cars through magnetic induction resonance. Cables implanted in the material of the roadway generate a specialized electromagnetic field that the car can convert into usable energy. The roads will also include communications equipment attuned to the unique energy signature of an electric car, alerting the road that an electric vehicle is present and to initiate the power generation process. This will allow properly equipped electric vehicles to recharge on the go, without needing to stop for extended periods to recharge, one of the biggest stumbling blocks cited in the adoption of electric vehicles thus far.

The roads the UK are experimenting with will be restricted for the time being, ensuring that regular vehicles do not impede the testing process. The government is committing 500 million pounds, or roughly $779 million, to these experimental roads over a five-year span. This technology is already in use in South Korea, powering rail systems with ranges of up to 15 miles, and will be combined with an added initiative to provide charging stations every 20 miles in the UK. The combination of options for drivers will help eliminate so-called “range anxiety,” which one advocate described as a combination of running low on gas and having one’s cell phone be low on battery simultaneously.

Recent Calvac Paving Project

Magnetic induction resonance works in much the same way as a powerful operatic voice can shatter crystal. When the voice and the crystal reach a similar resonance, the molecules in the crystal begin to vibrate rapidly and cause it finally to break. Instead of shattering or rupturing the battery, however, the cables the charging roads utilize will create a harmonic resonance within the battery that allows it to transform the signal from the roadway into usable power.

Because many roadways contain metal in addition to the native subgrade, road base and asphalt in the form of rebar, wire-mesh matting and metallic joints between road sections, the cables can use this metal as a part of the transmission system for the power. The metal components of the electric car can be employed as a receiver, directing the transmitted energy to the battery without the driver needing to stop, handle any charging devices or worry about whether or not the car will make it to the next charging station.

Major car production companies such as Audi are leading the research into this technology, which they believe will relegate internal-combustion vehicles to the status of horse and buggy. By working together to create a standardized plug-in system for use in garages, parking structures and ultimately at-home use, these car manufacturers believe they can make charging stations easier to find and thus make electric cars more attractive. The idea of “switching stations,” where a person can simply replace a drained battery with a fresh one and continue on, and the increased range of electric cars to around 250-300 miles per full charge depending on the type of car and battery size, will help expedite this process.

While paved roads are still very much a part of the future landscape, what drives over those roads and what lies beneath them may soon play a more crucial role than ever in our environmental integrity and ability to move people and cargo. Calvac Paving will be watching the trials in the UK with a great deal of interest, because we want to see if this technology truly is feasible and what the implications will be for the paving industry. If everything pans out as the equations and scientists claim, this could be a major breakthrough and a huge tectonic shift in how things are designed in both construction and automotive industries, as well as manufacturing and transportation as a whole. We think that’s a pretty big win, and look forward to this technology here at home!


Maintenance Mondays – Drive Lanes Removed & Replaced

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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.


Calvac Paving Is Hiring!

Calvac Paving

Calvac Paving, a San Jose based Asphalt and Concrete maintenance and construction Contractor is looking for Equipment Operators, Laborers and Skilled Workers. We are looking for full time workers and experience in Asphalt and Concrete construction is a plus.

 

Applications must be completed at 2645 Pacer Lane, San Jose, CA 95111

 

About Calvac Paving

Over the past 40-plus years, Calvac Paving has become one of the most experienced and reliable Asphalt and Concrete contractors in Central California. Our focus on individual project attention and meeting our STAKEHOLDER’S expectations has helped us to add scores of Property Managers/Owners, HOAs, Corporate buildings and campuses, Retail as well as Multifamily properties to our list of appreciative clients/stakeholders.

 

Calvac Paving Is Hiring


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

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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!