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Concrete Casting News from the Hill and Griffith Company

Article review: "U.S. Skills Gap is Hurting Manufacturing"

Posted by Carlos Gonzalez on Sep 13, 2018 12:51:47 PM

With a growing concern around the nations skills gap, companies look for a root cause. Guest post by Carlos Gonzalez with New Equipment Digest Magazine.

In 2017, the Committee for Economic Development (CED) embarked upon a “listening tour” of business leaders and parents to discuss firsthand information about workplace demands and aspirations for high school graduates. The listening tour made stops in five communities over the course of a year: Oakland, Calif.; Westfield, Mass.; Tupelo, Miss.; Marysville, Ohio; and Norfolk, Va.

Manufacturing is one of the main industries represented in the communities selected for the study and is a field that employs high school graduates without a higher-education degree. CED brought business leaders and parents together to figure out how they could make students ready to enter in-demand fields such as manufacturing, directly out of high school.

Cindy Cisneros, vice president of education programs at CED, explains the methodology of the study and how both parents and business leaders can contribute to career readiness for high school students.

U.S.-Skills-Gap-Hurting-Manufacturing-4

A builder on site discusses work with an apprentice. By 2020, 65% of all jobs in the economy are projected to require postsecondary education and training beyond high school.

How did CED choose the communities for the listening tour?

The five cities were chosen on the basis of achieving a diversity of geography, community demographics, and industry in which to conduct the focus group discussions. CED also drew from its broad network of member partners across the country to help identify sites. Invitations were extended to 10 business leaders who are representative of the regional economy, as well as 10 parents with children of varied age ranges from middle and high school. 

U.S.-Skills-Gap-Hurting-Manufacturing-2

An engineer teaches his student how to use a TIG welding machine. The skills gap can cost employers up to $23,000 a year per unfilled position.

Why does career readiness matter?

Career readiness has a long and somewhat complicated history in the United States. Following generations of pendulum swings from vocational tracking to college-for-all, recent years have seen an attempt to shift toward a more nuanced approach of preparing students for both college and a career.

Why this shift toward a middle ground? Despite some indications that our education system is improving following decades of standards-based reform, data show that too many young people in America are floundering. In the K-12 system, high school graduation rates are on the rise overall, yet attainment gaps persist: 88% of White students graduate within four years. However, their Black peers graduate at a rate of just 75%, and their Hispanic peers at a rate of 78%.

U.S.-Skills-Gap-Hurting-Manufacturing-3

A construction trainee learns technical skills on the job with her tutor. One report examining middle market companies found that 44% of executives report lacking candidates with the right skills.

Why do these figures matter?

By 2020, 65% of all jobs in the economy are projected to require postsecondary education and training beyond high school (35% at least a Bachelor’s degree, 30% some college or an Associate’s degree). Yet, if the attainment rates mentioned above hold steady, the supply of qualified candidates will fall short. Reports from employers already point to a skills gap, meaning a mismatch between the knowledge and skills of prospective employees and the competencies needed for available jobs.

U.S.-Skills-Gap-Hurting-Manufacturing-1

Two students work together on an engine in mechanical school. A national study found that 77% of employers believe that soft skills are just as important as technical, or hard, skills.

How can parents and business leaders help students develop these soft skills before they enter the workforce?

Both groups brainstormed a number of strategies to help students refine their soft skills while simultaneously strengthening their technical skills. All five communities supported the notion of work-based learning as a key to success. Discussions focused on providing students with opportunities to experience the full continuum, beginning as early as elementary school: awareness, exploration, preparation, and training. For example, the Marysville, Ohio community agreed that they could help school adapt goals to provide exposure to a future work life by allowing businesses to host career fairs and provide internships to high school students.

Implementing these ideas must begin with coordination and communication between parents and the business community, as well as collaboration with schools, in order to give students what they need to find and keep good jobs once they cross the graduation stage and enter the workforce.

(Click here to read the entire article.)

About CED

The Committee for Economic Development of The Conference Board (CED) is a nonprofit, nonpartisan, business-led public policy organization that delivers well-researched analysis and reasoned solutions to our nation’s most critical issues.

Since its inception in 1942, CED has addressed national priorities to promote sustained economic growth and development to benefit all Americans. CED’s work in those first few years led to great policy accomplishments, including the Marshall Plan, the economic development program that helped rebuild Europe and maintain the peace; and the Bretton Woods Agreement that established the new global financial system, and both the World Bank and International Monetary Fund.


Precast Concrete In Google News:

Precast concrete could mean better local roads in the future

PCI Mid-Atlantic Producer Awarded Contract with James Madison University

Louisiana DOT testing precast concrete ramp


 Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors, NSF potable water concrete release agents and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Casting Supplies, U.S. Skills Gap, Concrete Form Release

Review of AWWA Standard for Concrete Potable Water Prestressed Concrete Pressure Pipe & Concrete Steel Pressure Pipe

Posted by Hill and Griffith Company on Sep 6, 2018 11:04:40 PM

"The forms shall be cleaned thoroughly and coated with a form-release agent before each use."

Concrete Pressure Pipr 101

(Image from PUBLIC WORKS Magazine.)

I. Introduction

I.A. Background

There are two types of prestressed concrete steel-cylinder pipe:

(1) the lined-cylinder type, with a core composed of a steel cylinder lined with concrete and subsequently wire-wrapped directly on the steel cylinder and coated with mortar; and

(2) the embedded-cylinder type, with a core composed of a steel cylinder encased in concrete and subsequently wire-wrapped on the exterior concrete surface and coated with cement mortar.

The lined-cylinder type, which was first used in the United States in 1942, is furnished in sizes from 16 in. (410 mm) to 60 in. (1,520 mm). The embedded-cylinder type, which was developed later and first installed in 1953, is most commonly manufactured in sizes 48 in. (1,220 mm) and larger. Both types are designed for the specific combination of internal pressure and external load required for the project in accordance with the procedures outlined in ANSI/AWWA C304, Standard for Design of Prestressed Concrete Cylinder Pipe. Prestressed concrete steel-cylinder pipe is used for transmission mains, distribution feeder mains, pressure siphons (including river crossings), penstocks, industrial pressure lines, water intake lines, and other applications. In the manufacture of lined-cylinder pipe, the first step is to fabricate and hydrostatically test the steel cylinder with joint rings attached. The cylinder is then lined with concrete to form the core. The concrete is placed either centrifugally, by vertical casting, or by a radial compaction method. The concrete lining is cured and high-tensile wire is wrapped around the core directly on the steel cylinder. For a selected wire size, the tension and spacing of the wire are controlled to produce a predetermined residual compression in the core to meet design requirements. The wrapped core is then covered with a dense premixed mortar coating applied by a mechanical impact method. In the manufacture of embedded-cylinder pipe, the cylinder and joint rings are constructed and tested in the same manner as lined-cylinder pipe. The cylinder is encased in concrete by vertical casting and mechanical vibration to constitute the core. After curing, the wire reinforcement is wound under tension in one or more layers around the outside of the concrete core containing the cylinder, instead of directly on the cylinder. The exterior coating of premixed mortar is placed by impaction. 

Concrete Pressure Pipe Basics

(Image from PUBLIC WORKS Magazine.)

4.6.5 Concrete for pipe core.

4.6.5.1 General. The concrete in the cores may be placed by the centrifugal method, by the vertical casting method, or by other approved methods.

4.6.5.10 Placing concrete by vertical casting method. The concrete lining or core shall be cast on-end on a cast-iron or steel base ring with rigid steel collapsible forms for the concrete surfaces. The forms shall be designed to ensure that they will have smooth contact surfaces, tight joints, and that they will be firmly and accurately held in proper position without distortion during the placing of the concrete. The forms shall be designed to allow the pipe core to be removed without damaging the surfaces of the concrete. The forms shall be cleaned thoroughly and coated with a form-release agent before each use.

(Remember that any concrete form release used for potable water needs to be NSF approved, like Grifcote LV-50 Plus.)

The transporting and placing of concrete shall be carried out by methods that will not cause the separation of concrete materials or the displacement of the steel cylinder or forms from their proper positions. Adequate methods of mechanical vibration shall be used to compact the concrete in the forms and to ensure satisfactory surfaces. 


Precast Concrete In The Google and NPCA News:

Retaining Walls: Designing Better Solutions

Precast Concrete Pavement Slabs: Design and Construction Considerations

Annual NPCA Convention - Oct. 4 – Oct. 6, 2018 – Providence, R.I.


 

Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors, NSF potable water concrete release agents and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Casting Supplies, NSF Potable Water Concrete Release Agents, Prestressed Concrete Pressure Pipe, Concrete Steel Pressure Pipe, Grifcote LV-50 Plus, Concrete Form Release

Prestressed Concrete Cylinder Water Pipe Comparison to Bar Wrapped Water Pipe with Steve Smith

Posted by Hill and Griffith Company on Aug 30, 2018 11:59:55 PM

This video was produced to show how to select a large diameter water transmission main product, by Steve Smith (Pipe Industry Icon)  

Prestressed Concrete Cylinder Pipe Comparison to Bar Wrapped Pipe 1

Hello, my name is Steve Smith and I'm with Forterra Pressure Pipe. What I want to talk to you about today is two pipe products. Prestressed concrete cylinder pipe, which is we're looking at right here. Prestressed concrete cylinder pipe, what you see here is you can see the prestressing wire. This is six gauge wire, class three. It's got a tensile range of 252,000 to 282,000. You'll notice that the spacing between the wires, that term today is called the pitch, the pitch of the wire, means the space in between rod wrap to rod wrap. For instance, this looks like it could be a one inch pitch. You'll notice the mortar coating. The mortar coating is one inch over top of the cylinder. Okay. What we're gonna transition to now, I want to show you the difference between the prestressed pipe and what known as the bar wrap pipe.

 

 

This is bar wrap pipe. To the naked eye, one might say they look exactly the same. But you're gonna notice this is rod. It's not prestressing wire, it's rod. Wrapped at about 500 psi, and which it's got a heavy steel cylinder, which differs from the prestressed concrete cylinder pipe, which only has a 16 gauge cylinder.

Bar wrap pipe is rated typically zero all the way up to 250 psi.

The key difference is bar wrap pipe is a semi-rigid design. Semi-flexible if you will, versus prestress, which is a rigid design. So bar wrap pipe does rely on soil side support, much more important than say prestress. What this demonstrates here is the ability to be able to chip out the mortar coating.

Take the rod wraps and basically cut them and bend them out of your way, and this shows the application where we can actually weld a flange in the field.

Prestressed Concrete Cylinder Pipe Comparison to Bar Wrapped Pipe 3

What makes bar wrap unique, unlike prestress, is prestress, because of the wire wraps, you basically can't cut this pipe and make any modifications, because the wire is under tension. Where versus this pipe, because the rod is not under tension, this is a steel pipe design, it gives you the ability to cut section, this type of bar wrap pipe. If we go to the other side, I'll show you some other examples.

Prestressed Concrete Cylinder Pipe Comparison to Bar Wrapped Pipe 2

What you're looking at here is bar wrap pipe. Notice the rod. What this demonstrates is the ability to take say a 20 foot section of bar wrap pipe, you can literally cut the pipe in half. What you see here, we take the rod wraps and just peel a couple rods back, and what this shows the ability to weld a flange in the field, with the butt strap. That's something, quite frankly, that you could not do with the prestress concrete sonar pipe.

So when it comes to adaptability and repair ability in the field, bar wrap has become a favorite choice here in these. This just demonstrates a harness clamp joint. This is a harness style joint that's been around for many, many years. This is one form of restraint joint.

If we go back over here to the left, obviously this demonstrates our snap ring joint. This is snap ring joint. It's a joint, it was a Price Brothers design joint back in the early '70s, 1973. And it's joint ring we still use today.

We jump to the other side, you can see this is the insert. It basically allows the contractor to push the spigot into the bell. You simply tighten down, loosen a nut and tighten down this bolt. And the term we use, now the snap ring is engaged, means it's locked down. That you can see in this cut out section, because it's smaller diameter, how it locks in the spigot ring and keep it from backing out under thrust conditions.

(Thanks to Steve for the great video. Another thing to remember is that any concrete form release used for potable water needs to be NSF approved, like Grifcote LV-50 Plus.)


Precast Concrete In The Google and NPCA News:

Get Certified - NPCA’s Plant Certification Program assures a uniformly high degree of excellence

Take Your Career to a New Level With Precast University ® and the Master Precaster Program

Annual NPCA Convention - Oct. 4 – Oct. 6, 2018 – Providence, R.I.


 

Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors, NSF potable water concrete release agents and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Casting Supplies, NSF Potable Water Concrete Release Agents, Prestressed concrete water pipe, Bar wrapped concrete water pipr, Concrete Form Release

2017 NSF/ANSI Water Treatment and Component Standards

Posted by Hill and Griffith Company on Aug 26, 2018 11:02:29 AM

A new informative Annex H: Water quality criteria considerations for piping materials in contact with drinking water has been added.

Water is, of course, the liquid molecule that we need to sustain life. Any kind of contaminant in water can be detrimental not only to granting this basic need, but it can wickedly and unnecessarily introduce new health problems and even deter individuals from consuming it. Therefore, it is crucial that public water supplies remain clean while supporting a system by which most people in modern society live. (From the American National Standards institute site.)

Drinking Water System Components



NSF/ANSI 61-2017: Drinking Water System Components – Health Effects

This American National Standard sets health effects criteria for water system components, specifically the materials or products that come into contact with drinking water, drinking water treatment chemical, or both and can potentially impart chemical contaminants and impurities. System components covered include protective barrier materials (cements, paints, coatings), joining and sealing materials (gaskets, adhesives, lubricants), mechanical devices (water meters, valves), pipes, plumbing devices, and process media. Most governmental agencies in North America require compliance with NSF/ANSI 61 for water treatment and distribution products.

NSF/ANSI 61-2017 contains the following revisions: exposure and normalization criteria specific to concrete aggregate have been added, a new informative Annex H: Water quality criteria considerations for piping materials in contact with drinking water has been added, language regarding tank covers has been incorporated, allowable volumes of test assemblies have been updated, updated terminology on control samples has been included, lead content requirements have been updated, and updates have been made to several pass/fail values in Annex D on Drinking Water Criteria.


(Warning from  to manufacturers that don't comply with the standard when required. Their blog page.)

The SCAM

ENGINEERS, CONTRACTORS and OWNERS, BEWARE! There are manufacturers out there who continue to try to game the system, but their irresponsibility can easily become YOUR LOSS! Here is an excerpt from the EPA in a summary statement made about the SDWA Section 1417.

Since 1986, the Safe Drinking Water Act (“SDWA” or “the Act”) has prohibited the use of certain items that are not lead free and since 1996 the Act has made it unlawful for anyone to introduce into commerce items that are not lead free.

ANY MANUFACTURER WHO IS MISLEADING THEIR CUSTOMERS INTO BELIEVING THAT THEIR SYSTEM IS CERTIFIED TO THE STANDARD IS VIOLATING FEDERAL LAW AS OF JANUARY 4, 2014! There is no nice way to say this! Unfortunately, this irresponsible behavior has become commonplace within the industry as there have been many manufacturers who have put off certification believing the enforcement would be low.

I spoke with our third party lab regarding the testing of components and systems and this is what they said:

Manufacturers can request the testing and certification of either a component or system. If a client chooses to only certify a component, then only the component can be labeled and advertised as certified.

To clarify, standard NSF/ANSI 61 addresses several different types of potential contaminants, but not specifically lead content. Low lead requirements are defined separately in three different requirements:

• Federal lead law: “Reduction of Lead in Drinking Water Act” – Effective January 4, 2014
• California lead law: “The California health & Safety Code 116875”
• NSF/ANSI 372: Standard, not a law, providing test methods.
It is important to note that having compliance to NSF/ANSI 372 does not substitute certification to either the Federal or CA State lead laws.

If a manufacturer has a SYSTEM certification, this will be obvious to the user if they look at the certification document provided by the test laboratory. The QuantumFlo Certification is, without question, perfectly clear.


72-inch diameter Bar-Wrapped Concrete Cylinder Pipe.

Ameron supplied this 72-inch diameter Bar-Wrapped Concrete Cylinder Pipe. Bar-Wrapped Concrete Cylinder Pipe (CCP) consists of a steel cylinder lined with concrete or cement mortar, then helically wrapped with a mild steel bar and coated with dense cement mortar. CCP is designed and manufactured in accordance with the American Water Works Association (AWWA) Standard C303 and AWWA Manual M9, and is normally supplied in standard diameters of 18 to 72 inches for operating pressures up to 400 psi. Pipe has been manufactured in larger sizes and for higher pressures based on the concepts of this standard.


Precast Concrete In The Google and NPCA News:

Louisiana DOT testing precast concrete ramp

New Precast Concrete Educational Courses Highlight Innovative Technologies

Precast concrete barn has all the bells and whistles for 280 Alberta dairy cattle


 

Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors, NSF potable water concrete release agents and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Casting Supplies, NSF Potable Water Concrete Release Agents, Concrete Form Release

Protect Your Precast Forms with Reactive Release Agents and Rust Preventatives

Posted by Hill and Griffith Company on Aug 18, 2018 8:17:40 PM

Taking care of your precast concrete forms extends their life and protects a valuable investment.

Precast-Concrete-Careers-6

It starts with day-to-day mainentance. Steel form problems can happen with poor cleaning or excessive use of wire brushes or sandblasting. They can also be damaged by vibrators.

The selection of a good concrete release agent is another important aspect of form care. There are two main types of concrete releases.



Diesel fuel, greases, used motor oil, etc. barrier type products provide a barrier between the form and the concree allowing it to strip. These provided a good release, but cause surface voids, staining, and over all poor finished appearance. They are harder to apply due to their higher viscosity.

precast-concrete-form-maintenance-1

Reactive type are chemically active and contain compounds that react with the free lime in the concrete to produce a soap-like film between the form and the concrete. This type of release agent is the most widely used. They are only require a thin film to produce a stain-free, void-free concrete surfaces. Reactive type release allow the form to strip cleaner.

Proper application of release agents is necessary for economy and for producing the best product possible and for minimizing form clean up.

Another aspect of concrete form care is protection in storage when they are out of service between jobs. The forms need to be protected from rust and corrosion. Some use grease, diesel fuel, or release agent but a rust preventative is a beter choice. For your rust preentative know the quality of protection, length of protection, ease of application, and ease to remove.

Formwork is a big investment for producers. Proper care insures product quality and extends their life. It will make your concrete business more profitable.


Precast Concrete In The Google and NPCA News:

Precast concrete could mean better local roads in the future

Precast concrete barn has all the bells and whistles for 280 Alberta dairy cattle

Senior Living Community Selects Precast Concrete for New Construction


 

Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Form Seasoning, Concrete Casting Supplies, Rust Inhibitors, Concrete Form Release

Precast Wall Concrete Form Release Application Video

Posted by Hill and Griffith Company on Aug 25, 2016 10:33:02 AM

(We love "How It's Made" and this episode shows how precast concrete walls are made and includes video of the application of release agent.)

Concrete-Form-Release-Application-Video.jpgPublished on May 14, 2015 by the Science Channel.

"A mix of limestone gravel, minerals and additives are mixed into a slurry. After a test sample is hardened and tested, workers pour it into pre-made molds."

 Here's a list of the sections of the video:

  • Concrete mixing

  • Form set up

  • Foam letter placement for imprint on wall

  • Form release application

  • Steel cable placement and pre-tensioning

  • Rebar placement

  • Wire mesh placement

  • Pour first layer of concrete

  • Place second set of rebar and mesh

  • Place insulating foam

  • Pour second layer of concrete

  • Curing for three days
  • Sand blast decorative parts of the wall

  • Wall placement

 


Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Form Seasoning, Biodegradable Concrete Form Release, Concrete Casting Supplies, Concrete Voids, Concrete Form Release

"Precast 101," illustrating concrete form release agent application

Posted by Hill and Griffith Company on Aug 18, 2016 5:10:40 PM

(This week's post is a video share from Oldcastle Precast, view the YouTube Channel here. Published on June 19, 2015, it's the complete story of design, engineering, construction, production / pouring of concrete, form release, storage and delivery of the final product to the customer. Very nicely done! Thank you, Oldcastle Precast.)

Concrete-Form-Release-Agent-Application.jpg

Precast concrete is a construction product produced by casting concrete in a reusable mold or "form" which is then cured in a controlled environment. This allow maximum quality control over the process and results in a consistently durable, high quality product. From here it is transported to the construction site and lifted into place.


Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Form Seasoning, Biodegradable Concrete Form Release, Concrete Casting Supplies, Concrete Voids, Concrete Form Release

Care of Forms and Use of Concrete Form Release Agents

Posted by Hill and Griffith Company on Aug 11, 2016 11:41:40 AM

 

(This week's post is an educational article by Bill Rostine from "Pre-Cast Concrete News." )

Concrete-Form-Release-Agent-Application-1.jpgConcrete formwork is one of the biggest investments a precast or prestress plant has. Therefore, taking care of the forms extends form life and protects a valuable investment. This makes economic sense and contributes to a healthy bottom line.

Care of concrete forms starts with the day-to-day use. Problems on steel forms can occur with inadequate cleaning or with excessive use of wire brushes or sandblasting. Form surfaces can also be damaged by internal vibrators.

Another important aspect of form care is the selection and proper application of a good release agent. Proper application of release agents is necessary for economy and for producing the best product possible and for minimizing form clean up. 

There are three main types of release agents.

The first is the barrier type. These products, as the name implies, provide a barrier between the concrete and the form allowing it to strip. The original, modern-day, form oils were barrier types-diesel fuel, greases, used motor oil, etc. These allowed for a good release, but negatively affected product quality by causing surface voids, staining, and over all poor product appearance. They are heavier in nature and are harder to apply due to their higher viscosity.

The second type of release agent is the reactive type. These are chemically active and contain compounds that react with the free lime in the concrete to produce a soap-like film between the form and the concrete. This type of release agency is the most widely used. They are easily applied in a thin film. Because they can be applied in a thin film by spraying, wiping, or brushing, you can produce stain-free, void-free concrete surfaces. Reactive type release agents applied in a thin film allow the form to strip cleaner which saves on labor costs related to form cleaning and extends the life of the form.

The third type of form release agent is a combination of the other two types.

Grifcote-Concrete-Form-Release-Agent-Sizes.jpgCoating manufacturers and coating formulations, including those of release agents, were affected by the Clean Air Act of 1990 passed by Congress. This law allowed the Environmental Protection Agency to set into motion a process to limit nationwide the amount of Volatile Organic Compound (VOC) that a coating should contain. VOC’s are thought to react with sunlight and cause ground level ozone or smog. The original law called for testing or different VOC’s to see how much, if any, reactive capability a given VOC had with sunlight and the formation of smog. When this testing wasn’t done properly many coating manufacturers (mainly California paint companies and other concerned parties) took the EPA to court to fight the law. After several court fights, lawsuits and rulings during the1990’s, the EPA prevailed and the law limiting VOC’s was allowed to take effect. In September of 1999 release agent manufactures and concrete producers were required to make and use limited VOC products. Some companies, including Hill and Griffith, saw this coming years in advance and were already producing VOC compliant products. All new products were formulated based on the new EPA law. Some states, such as California have stricter rules than that passed nationally.

There are four main application methods-spraying, wiping, mopping  or brushing and dipping. Spraying is probably the most common and efficient method of application. Care should be taken to avoid over application for the reason mentioned earlier. An extremely thin film of release agent can be applied with proper equipment and technique. Working application pressures of 35 to 50 psi are best. Pump unit sprayers or centralized systems with air pressure regulators give a good consistent pressure and work well. Higher pressures put more airborne particles in the air throughout the plant and can be harmful to personnel in the plant. Lower pressures allow for over application, puddling in the form, and waste. A flat fan spray nozzle of .5 gpm maximum size will work with many release agents. Better yet is a flat fan spay nozzle of .1 or .2 gmp spraying a good thin release agent. Many of these thin, chemically active release agents are more expensive per gallon, but with coverage rates at 2000-2500 sq. ft. per gallon the applied cost is much less than a cheaper, less effective release agent. A second type of application is wiping on the release agent. This can be done with a rag or sponge with excellent results. Architectural precasters like this method because over application is eliminated. Some burial vault manufactures use a sponge for application because they clean the form with every application of release agent. A third type of application is by mopping or brushing. When using this method over application can be a problem. As with wiping, the application device must be wrung out in order to achieve the desired results. If puddles occur, they should be wiped up. A fourth method of application is dipping. Dipping systems are fast, labor efficient, and assure total coverage of the form. Dip tanks collect the excess release agent that drains off the form. Over application is probable, but this type of application works well in some operations. Whatever method is used for applying the release agent care should be taken to keep it off reinforcing steel.

Concrete-Form-Rust-Preventative.jpgAnother important aspect of form care is protection of forms in storage. Precast concrete producers, especially those with diverse product lines, occasionally take forms out of service between jobs. The investment in forms needs to be protected from rust and corrosion. Some producers user grease, diesel fuel, or release agent and apply it to the forms. Application with these products needs to be done irregularly with limited protection of the forms. A better choice is a good rust preventative. When shopping for the best product, there are four things to consider.

First is quality of protection, second is length of protection, third is ease of application, and fourth is ease of removal. 

Formwork is a major investment for precast concrete producers. Utmost care should be taken to insure product quality and exend the life of these valuable assets. Money spent taking care of forms now can save hundreds or thousands of dollars in the future and make a concrete business more profitable.


Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

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We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
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On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
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Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Form Seasoning, Biodegradable Concrete Form Release, Concrete Casting Supplies, Concrete Voids, Concrete Form Release

How Can I Eliminate Surface Concrete Casting Voids?

Posted by Hill and Griffith Company on Aug 4, 2016 2:32:41 PM

 

(From Smooth On Concrete Casting Products. This is one of the best Q&A for concrete casting defects we have seen. Enjoy!

 

Concrete-Voids-1_copy.jpgHOW CAN I ELIMINATE SURFACE CONCRETE CASTING VOIDS?

Surface voids (small holes, also known as bug holes or pitting) found on the surface of concrete castings have affected anyone who has ever cast concrete. A significant number of concrete casting voids must be post finished or discarded, resulting in wasted product, time and labor. Understanding the causes of surface voids and what can be done to minimize them is the first step to a more efficient and productive casting operation.

The following information has been compiled through our (Smooth On Concrete Casting Products) experience with professionals who cast concrete for a living. Some of the tricks found here are results of many years of research and development. Although one may not find all the answers here, many of the common problems encountered when casting concrete will be addressed.

Question: What are surface voids?
Answer:
Surface voids are the cavities or little holes that appear on the surface of concrete castings. Surface voids (commonly known as pitting) are referred to as "bug holes" or "fish eyes". These voids may produce an unacceptable appearance on the surface of the finished casting.

Question: How are surface voids caused?
Answer:
Surface voids are generally attributed to the following three factors: release agent, water or air (sometimes a combination of the three).

Concrete-Voids-2_copy.jpgQuestion: How does a release agent affect the surface of a concrete casting?
Answer:
Release agents act as a "lubricant" between the mold and the concrete itself. The proper application of a release agent will yield castings without surface voids. However, when a release agent is over applied, it may "pool" or "puddle" on the lower extremities of the mold. As the concrete is poured into the mold these pools prevent the concrete from filling in all the detail. When the casting is removed from the mold voids will be apparent in the areas where pooling occurred. Vibration magnifies this problem by forcing additional release agent into the lower extremities of the mold. Voids caused by too much release agent are recognizable as small spherical voids on the surface
of the finished casting. These voids usually measure about 1/8" (.31 cm).

Question: How does water cause surface voids?
Answer:
Similar to release agents, water is also trapped against the mold's working surface resulting in voids. As the concrete cures and the residual water evaporates, a cavity is left behind on the surface of the casting. Vibration also tends to force water from the cementious material, however most voids caused by water are a result of a high water to cement ratio. Similar to release agents, water is also trapped against the mold's working surface resulting in voids. As the concrete cures and the residual water evaporates, a cavity is left behind on the surface of the casting. Vibration also tends to force water from the cementious material, however most voids caused by water are a result of a high water to cement ratio.

Question: How does air cause surface voids on my finished concrete casting?
Answer:
In most circumstances, air voids have an irregular shape and tend to be much larger (1/2" or 1.27 cm.) than those caused by water or release agents. The air voids are caused by air trapped between the mold surface and the concrete. They generally appear in low slump concrete and can be found underneath irregular (non-spherical) shaped pieces of crushed aggregate.
This is a result of having too little mortar to fill the spaces around the aggregate. Voids caused by air may also be found in castings that have severe undercuts.


HOW TO ELIMINATE VOIDS IN A CONCRETE CASTING:

While many variables must be considered in the elimination of surface voids or bug holes in concrete castings, there are a number of precautions that can remedy this unsightly problem.

Careful preparation and methodical practices can eliminate even the worst of surface voids. The following section describes procedures and materials that will produce finished castings that even the most discerning eye will accept.

Question: Will adding more mortar to the concrete assist in reducing surface voids?
Answer:
Yes. Increasing the amount of mortar in the cementious material will help make the material more fluid. A mixture that has a higher mortar content will assist in encapsulation of the aggregate. By encapsulating the aggregate, mortar also provides a chimney or venting system that will allow air and water bubbles to escape from the mixture. During vibration these bubbles will rise through the mortar and escape through the opening of your mold. A higher mortar content in your mixture also allows larger pieces of aggregate to easily move during vibration and thereby release any air that may have been trapped.

Question: What will happen to my casting if I use a larger aggregate?
Answer:
Using a larger aggregate may cause more surface voids because air is entrapped under the irregular shapes of this material. There is also a larger volume of voids between larger aggregate pieces than smaller pieces. It is therefore recommended that a smaller aggregate be used or that a smaller aggregate be mixed with the larger particles. The smaller aggregate will act as a "roller system" to assist in turning the larger pieces of aggregate during vibration. It is recommended to use aggregate that passes through a number 50, 100 or 200 sieve.

Question: Does the type of cement I use in my mixture make a difference?
Answer:
Cement acts as a lubricant during vibration and allows larger pieces of aggregate to move around freely. Therefore it is recommended that a very fine cement be used to achieve a more fluid consistency. Fly ash, which is finer than cement particles, will increase the lubricity of the cement even further.

Question: What precautions should I take if my concrete has a low water-cement ratio?
Answer:
If the concrete you are casting has a low water-cement ratio, more mixing time will ensure that water and air bubbles are forced away from the aggregate and thereby eliminate the voids on the casting surface. Low water-cement ratio concrete also requires an increased vibration period.

Question: I've heard that adding plasticizers to my concrete mixture will help eliminate surface voids. Is this true?
Answer:
Yes. The addition of plasticizers are used effectively in creating large slump increases. The benefit of using a plasticizer is that these large increases can be attained without effecting the water-cement ratio. The result of increasing the slump will assist air, water and aggregate to move more freely throughout the mixture. Although plasticizers will permit a large increase in slump, the concrete will begin to set much quicker. This means that there is a much smaller time period for the concrete to be vibrated. In order to eliminate surface voids from appearing we recommend using a release agent in tandem with plasticizers. The release agent will allow the concrete to move freely and force voids away from the surface of the casting

Question: What type of mold or form material should I use?
Answer:
Form or mold surfaces be as smooth as possible to decrease the surface tension between the concrete and the mold. Rubber molds are being used more and more for just this reason. The proper release used on a rubber mold will give the best possible surface.

Question: I'm vibrating the concrete, but still have bug holes in the casting?
Answer:
This occurs because air and water bubbles are the lightest elements of the concrete and will naturally flow to the most fluid portion of the mix. It just happens that this area is next to vibrator. So if you are using an external vibrator, the form or mold should be hammered. Hammering allows the mortar to flow toward the area being hit, consequently pushing air and water bubbles to the opening of your mold. This technique is recommended for molds with deep undercuts, where air and water bubbles tend to be predominate.

Question: How beneficial are release agents?
Answer:
Not only do release agents assist in eliminating surface voids, they also prolong the life of your mold. However, choosing the correct release agent and proper application are extremely critical. Various release agents will provide different surface finishes of your concrete casting. We recommend a chemically active release agent.

The amount of release that is applied to the mold or form will greatly effect the surface of your casting. Excess release agent tends to consolidate into spheres that cause bug holes. Too much release agent can be evidenced by voids on the lower portions of your casting. Applying release agent in a thin coat will eliminate these voids.



HELPFUL HINTS TO VOID FREE CASTING:
As any professional caster will tell you casting concrete is not an exact science. There are many variables and therefore no way to ensure void free castings. Voids can be minimized, however, and the following hints are offered to improve your chances for success.

Hint # 1
Extend the mix time to help break up any residual air or water bubbles. This will promote a more uniform and workable consistency.

Hint # 2
Make sure to that release agents are applied in thin films. This will eliminated any pooling or puddling in the lower portions of your mold.

Hint # 3
Lower the viscosity of cement by adding sand or fly ash. This allows large aggregate to move more freely and reduces the amount of air entrapment.

Hint # 4
Use aggregate that is more uniform in shape. Irregular shaped pieces of aggregate tend to make the concrete less fluid.

Hint # 5
Techniques used during vibration can eliminate most surface voids. Vibrating both the outside and inside of your mold will draw most air and water bubbles away from the surface of the concrete. Hammering the mold can eliminate any residual voids.

Disclaimer
This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.


Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Form Seasoning, Biodegradable Concrete Form Release, Concrete Casting Supplies, Concrete Voids, Concrete Form Release

Concrete Pipe - Its History and Production.

Posted by Hill and Griffith Company on Jul 28, 2016 2:06:41 PM

(From the Portland Cement Association's web site.The PCA is a powerful and vocal advocate for sustainability, jobs creation, economic growth, infrastructure investment, and overall innovation and excellence in construction throughout the U.S.)

Concrete-Form-Release-Agent-1.jpgConcrete pipe has a well established history and reputation for being a long lasting, serviceable material. The Cloacae Maxima, built in about 180 B.C. as part of Rome's main sewer system, was constructed mainly of stone masonry and natural cement concrete. More than 2,000 years later, portions of the concrete sewer are still in use.

Modern day concrete sewer systems emerged during the mid-19th century when the public became conscious of the need for sanitation to control the spread of disease. The earliest recorded use of concrete pipe in the United States is a sewer installation built in 1842 at Mohawk, N.Y. Other New England cities followed suit and installed concrete pipelines in the second half of the nineteenth century. Many of these concrete pipelines are still in use today.

Milestones in development include the production of the first reinforced pipe in 1905, the invention of prestressed pipe in the 1930s, and the manufacture of the first steel-cylinder prestressed pipe in 1942. 

Sizes can range from four inches up to 17 feet in diameter. Although pipe can be manufactured in a variety of shapes, there are five standard shapes: circular, horizontal elliptical, vertical elliptical, arch, and rectangular. The pipe shape selected for a project depends on the topography of the site, importance of hydraulic and structural efficiency, erosion and deposition in the stream channel, and cost. Most often, the preferred pipe shape is the one that will alter the natural drainage flow the least.

Concrete-Form-Release-Agent-2.jpgFive Methods of Producing Pipe Made of Concrete

As with all concrete products, the basic materials are portland cement, aggregate, and water. There are five basic methods of producing pipe. Four methods -- centrifugal/spinning, dry cast, packerhead, and tamp-entail using a dry concrete mix. The fifth method, wet casting, uses a high-slump concrete mix. Wet-cast concrete mix usually has a slump less than four inches and is most frequently used for manufacturing large diameter pipe.

These types of pipe serve as a conduit material for irrigation, water supply lines, sanitary sewers, culverts, and storm drains. Culverts, usually made with arch-shaped concrete, are used to carry water under highways in non-urban areas. Storm drain systems for cities and towns are becoming more important as communities become larger and more densely populated. Recent major floods and the resulting damage only emphasize the need for efficient drainage systems.

Subsurface drainage carries away water below the surface of the pavement. This water reduces flow support capacity of the base and subgrade material causing potential damage to roads, airport runways, and building foundations. Many farm fields depend on proper underground drainage for their cultivation. Thousands of square miles of otherwise arid land rely on concrete irrigation pipe to supply water for farmland. Additionally, most of the large cities in the United States a pipe system made of concrete to transport their water supply.

More information at the American Concrete Pipe Association web site.


Hill and Griffith Customer Service

We're known for our hands on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water concrete form release, non-petroleum concrete form release, biodegradable concrete form release, rust inhibitors and concrete dissolver products that suit your needs.

Hill and Griffith Samples

Product Samples

We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »

 

Hill and Griffith Customer Service

Technical Services & Support

On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »

 

Bulletins and Technical Papers for Concrete Casting Products

 

Tags: Concrete Forms, Concrete Form Release Agents, Concrete Release Agents, Concrete Form Seasoning, Biodegradable Concrete Form Release, Concrete Casting Supplies, Concrete Pipe, Concrete Form Release

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