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Concrete Casting News from the Hill and Griffith Company

Stop by Booth 1427 at the 2020 Precast Show in Ft. Worth thru Saturday

Posted by Hill and Griffith Company on Mar 6, 2020 11:38:40 AM

HG 2020 Precast ShowIMG_2592 560

Left to right: Bob Waterloo, Tom Dempsey, Mike Lawry, Angela Cox and Barry Morgan will help you with your precasting needs.

The Precast Show is the largest precast-specific trade show in North America and the one place where you can find the industry’s most important suppliers and foremost equipment experts under one roof. We are looking forward to seeing you March 5-7, 2020, in Fort Worth, Texas.

The Precast Show is sponsored by the National Precast Concrete Association and the Precast Prestressed Concrete Institute with additional collaboration from the Canadian Precast Prestressed Concrete Institute and the Cast Stone Institute.

HG Concrete ad

Grifcote® and Cast-O-Magic Concrete Form Release Agents

VOC Compliant, NSF Certified and Biodegradable Release Agents for all Concrete Applications

THE PERFECT RELEASE

Industry Leading Performance and Quality
Trained technicians are available to visit your site, determine your needs and design the right product for you.

• Gricote FR-50 & PR-5S voe - Workhorse Release
• Grifcote LV-50 Plus - NSF Certified for Potable Water - Release
• Grifcote Bio-Gold - Environmentally Friendly Release
• Grifcote CC-1S0 VOC - Premium Seasoning Agent
• Cast-O-Magic, Con-Solver and Liquid Chisel
• Corrosion Inhibitor for Steel Forms

https://precast.org/theprecastshow/


More News from the Precast Show


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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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, Casting Solutions, Concrete Casting Products, Concrete Casting Supplies, Concrete Casting, Precast Concrete, Precast Show, Concrete Form Release Agent, National Precast Concrete Association

Producers' Guide: Form Release Agents

Posted by M.K. Hurd on Mar 5, 2020 8:00:00 AM

Excerpt from the February 2000 Concrete Construction Article by M.K. Hurd

Concrete form-release agents represent only a small fraction of the cost of a manufactured concrete item, but they have a big influence on the quality and success of the concrete surface.

Though no American Concrete Institute or ASTM standards define these products, common usage suggests that form release agents are materials containing proprietary reactive ingredients specifically formulated for use on concrete forms. ACI 301-96, “Standard Specification for Structural Concrete,” does, however, give performance-based requirements for release agents. Section 2.2.1.30 says to use “commercially manufactured form-release agents that will prevent formwork absorption of moisture, prevent bond with concrete, and not stain concrete surfaces.”

Concrete Form Release Application photo

Today, precasters can choose from among hundreds of form-release products, and new ones are still being developed. Many changes have been introduced as manufacturers scramble to meet federal and state environmental regulations, particularly with respect to volatile organic compounds (VOCs).

With the myriad form-release products available, how do you select the best one for a particular application? Here are a few of the fundamental questions you should ask:

  • On what form surfaces can it be used?
  • Will it provide clean, easy release without damage to either the concrete or the form?
  • Will it produce a stain- and blemish-free concrete surface?
  • Is it compatible with admixtures in the fresh concrete and with surface coatings that may be applied later to the hardened concrete?
  • Is it ready for use without site mixing, and is it appropriate for anticipated casting and curing temperatures?
  • Is it user-friendly and compliant with environmental regulations?

The table on pages 61-68 answers some of these questions and summarizes manufacturers’ recommendations for many currently available form release products. How release agents work Release agents are classified by how they work rather than what they contain. Two basic categories are barrier agents and chemically active agents (also referred to as reactive agents). Some release agents are a combination of the two types. Barrier-type release agents create a barrier between the form surface and the fresh concrete, preventing the concrete from sticking to the form

Read More

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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 Bulletins and Technical Papers for Concrete Casting Products

Tags: Concrete, Casting Solutions, Concrete Casting Products, Concrete Casting Supplies, Concrete Casting, Precast Concrete, Concrete Form Release Agent, Concrete Construction Magazine

Composition of Concrete Release Agents

Posted by Jonathan Meier on Feb 28, 2020 2:14:18 PM

Content from Civil Engineering

The quality of the concrete finish is affected by many factors. These include the concrete mix design and  its constituents, the formwork, the compaction, the temperature and the curing process and also the mold or formwork release agent used. The influence of the release agent is described below and advice is given on how to select and use concrete release agents correctly.

Composition of Release Agents

Release agents can be formulated from up to three different types of ingredients.

  • Release Film Formers
  • Additives
  • Thinners

Spraying Concrete Release Agent

Release Film Formers

These include the base materials, which are largely responsible for the release effect (usually various oils).
Used or waste oil was once the main concrete release substance, but these should not be used nowadays due to their quality fluctuations and also for environmental reasons. In addition to mineral oil distillates and simple raffinates (with a variable hydrocarbon content), there are now high-grade mineral oil products on the market (such as technical white oils and paraffin oils) and it is possible to obtain low-aromatic or practically aromatic free oils – depending on the refining process and conditions (e.g. medical white oil). The lower the aromatics content, the more environmentally friendly and easy to use this product is. Special synthetic oils can also be obtained from paraffin wax by the hydrocracking process. Some products which are used as release agents are rapidly biodegradable, such as vegetable oils, but these are extremely sensitive to temperature, unlike the synthetic oils, which can safely be used over a broader temperature range.

Additives

These are materials used to achieve additional or intensified effects and to improve product stability. They include release boosters (usually fatty acids or their derivatives), wetting agents, rust inhibitors, preservatives and surfactants required for emulsions. Most of the release agents in use today contain additives which react chemically with the concrete (to disrupt the setting process). It is then much easier to separate concrete from formwork and a more general-purpose product can be produced. This effect occurs because these fatty acids, or their derivatives, react with alkaline hydroxides in the cement to form calcium soaps and water.

Thinners

These products act as viscosity reducers for the release-film formers and additives described above. Their purpose is to adjust the workability, layer or coating thickness and the drying time before concreting can take place. Thinners are generally organic solvents (usually aliphatic hydrocarbons) or water in the case of water-based emulsion products.

Read More

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

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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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Hill and Griffith Customer Service

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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, Casting Solutions, Concrete Casting Products, Concrete Casting Supplies, Concrete Casting, Precast Concrete, Concrete Form Release Agent, Civil Engineer Magazine

The Importance of Precast Concrete Cistern pH

Posted by Jonathan Meier on Feb 21, 2020 2:34:44 PM

Why you should only use a concrete tank to store drinking water

Jonathan Meier with Rain Brothers LLC covers the basics.

Concrete cisterns are, in our experience, the best type of tank to use for underground drinking water systems. Rainwater tends to have a lower pH (acidic), while concrete has a higher pH (alkaline). As rainwater fills a concrete tank, the concrete then actually helps neutralize the water and balance the pH, if not slightly alkalinize it, which is why, after the cistern has gone through a few empty-full cycles, a litmus test of your cistern water would reveal a pH of between 6-8 – the optimal range for a good drinking water system.

Precast Concrete Cistern for Drinking Water

While concrete cisterns help neutralize acidic rainwater, initially, the residual concrete dust from the manufacturing/casting of the tanks will elevate the water's pH to high alkaline levels (10-11). This is completely normal, though for new concrete cisterns, precautions should be taken to get water down to 7-9 range. There are two approaches to managing this initial alkalinity:

1) Flush the tank. For this method, we recommend hauling in a load of water from a local water hauler (in Ohio, a list of water haulers can be obtained through your County's Department of Health or from the Ohio Department of Health Office of Environmental Health). You can then use the hauled water to rinse the walls of the tank to remove as much concrete dust residue as possible. Do not drink this water, but instead either pump it out after a few days or use it for non-potable applications (flushing toilets, showering, irrigation, etc.). Occasionally, it may take two and sometimes three full empty-fill cycles before the water inside the tank reaches a safe pH level of 9.

2) Pressure wash/scrub. For this method, once the tank has initially been installed, use a pressure washer with a 55-gallon drum of clean water and a cup of unscented chlorine bleach to pressure wash the walls of the tank. You may also use a scrub brush with a bucket of water/chlorine mix and hand scrub the walls. Doing so will remove the majority of concrete dust from the side walls. Then, when possible, pump out the water from the bottom of the tank (note: you may have to put more water into the tank to be able to pump the "dirty water" out). If it is not possible to pump out the bottom of the tank after pressure washing/scrubbing, then get a load of hauled water into the tank but do not drink water from this load. Again, use that first load for non-potable uses only.

(Washing the tank will also remove the NSF approved concrete form release. Forty-eight U.S. states have legislation, regulations or policies requiring drinking water system components to comply with, or be certified to, NSF/ANSI 61.)

These precautions may sound intimidating, but the reality is that the work on the front end is minimal compared to the lifetime of fresh, clean water you will receive from a concrete cistern. 

As always, thanks for reading.

(Thanks to Rain Brothers LLC for this article and video below.)


For additional information on the proper concrete release agent to use for concrete drinking water tanks, read these articles published in Precast Inc. by the Hill and Griffith Company:

Precast Concrete in Google News and NPCA, National Precast Concrete Association


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."
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Hill and Griffith Customer Service

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 Bulletins and Technical Papers for Concrete Casting Products

Tags: Concrete, Casting Solutions, Concrete Casting Products, Concrete Casting Supplies, Concrete Casting, Precast Concrete, Concrete Form Release Agent, NSF/ANSI 61 Potable Water, Precast Concrete Drinking Water Tanks

Coating Tilt Up Concrete Walls

Posted by Hill and Griffith Company on Oct 24, 2019 3:55:17 PM

Originally published in the March 2011 issue of Concrete Construction

Q: The painted surfaces of some of the tilt-up concrete walls on our projects seem to develop blisters, peeling, or flaking shortly after application. Sometimes this occurs after it rains. Is there anything different about tilt-up walls that makes this happen?

A: As with any paint or coating project, the key to good results is paying attention to the three Ps: Prep, Prime, and Paint. Procedures for painting and coating concrete surfaces are different from other surfaces, and tilt-up concrete surfaces do require special preparation.

Causes of Defects on Tilt Up Concrete Walls

Surface Preparation: The most likely reason for blistering and peeling in a tilt-up wall, especially if it occurs shortly after it rains, is failure to remove the mold release agents and bond breakers used for casting the concrete component.

This is the big difference between tilt-up concrete and other forms: It is cast on the jobsite in concrete forms. After the concrete wall or column has cured, a mobile crane tilts the piece up and moves it into place, where it is braced into position and secured. Painting contractors may not always be fully aware of this because they arrive on the jobsite after the walls are in place.

To prevent the concrete from adhering to the molds, contractors apply release agents, or bond breakers, to the mold before the concrete is poured. These release agents can be solvent-based, water-based, oil-based, silicone-based, silicone-free, silicone water-based and many other proprietary combinations. But they all perform the same function—they create lower surface energy between the concrete form and the concrete to mitigate adhesion. The objective is to be able to lift the cured concrete from the casting mold smoothly and cleanly.

Unfortunately, release agent residue also can inhibit adhesion of coatings and paint to the concrete surface. Most painting contractors are aware of this, and paint companies do a good job of educating painters about the need to remove release agent residue before painting or coating tilt-up concrete surfaces. Power washing at the specified pressure using the specified cleaning solvent should do the trick, but there are two cautions.

One, be methodical and thorough when power washing. Two, there is a trend toward making release agents and paints/coatings more compatible, but it is always prudent to power wash the surface first. Even with “compatible” release agents, if too much was applied to one area, it could swamp the system and adversely affect coating adhesion.

All concrete surfaces must be washed before coating to remove dirt, dust, and excess sand anyway, so always take the extra step of power washing tilt-up concrete to remove any release agent residue, whether they are compatible or not.

Read More


Additional news from Concrete Construction

Repairing Bugholes

Concrete Form Maintenance


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

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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 Form Release Agents, Concrete Casting Products, Concrete Casting Supplies, Concrete Pipe, Concrete Safety, Precast Concrete, Grifcote FR 50 Concrete Form Release, Bio Gold Concrete Form Release, Grifcote, Concrete Construction Magazine

5 Options for Dry-Cast Concrete Pipe Dip Tank Maintenance

Posted by Hill and Griffith Company on Oct 10, 2019 2:24:06 PM

Originally published in the May-June issue of 2015 PRECAST INC, by Bob Waterloo

Maintaining the optimum reactive level of form release agents in pipe production dip tanks ensures performance and quality. 

Dip tanks play a critical role in the dry-cast pipe production process for many manufacturers. The reactive properties of the fatty acids in the form release agent enable the pipe to release from the pallet/header smoothly. Here’s the problem. The cement/concrete residue left behind when headers are dipped starts to negate the reactive properties of the fatty acids.

Left unchecked, the form release agent eventually begins to lose its effectiveness, pipes will not pull easily from the headers and quality could suffer. The solution: implement a regular program of monitoring and maintenance that keeps the form release at the optimum reactive release level and reduces replacement and disposal costs.

Precast Pipe Dip Tank Maintenance

Benefits of a dip tank
Reactive form release agents are the accepted standard in today’s precast and pipe-forming operations. Fatty acids, which are found in an infinite number of blends, are the most commonly used reactive material. Fatty acids have the unique ability to react with the free lime on the surface of the concrete, which results in a nonviolent chemical reaction. This neutralization (or saponification) forms a metallic soap, allowing the product to release easily.

There are several benefits to using a dip tank to apply form release during pipe-forming operations, including complete coverage, proper release and reduced chance of operator error. However, a common occurrence when using this method of manufacturing is increasing difficulty with “pulls” or “tip-outs” during stripping over a period of production time. This is generally the result of decreased reactive material in the dip tank as contaminants enter the system and negate some of the reactive material.

Maintaining the dip tank
Two areas must be addressed in the preventive maintenance program for this type of equipment:

  1. Regular maintenance to remove sludge that accumulates in the bottom of the dip tank
  2. Regular maintenance of the release agent’s reactive levels for effective release

The sludge generated in the dip tank includes contaminants from previously dipped headers/joint rings. These contaminants negate the reactive portion of the form release. As the reactive portion of the release agent gradually decreases, the possibility of concrete sticking to the headers increases, causing a more difficult release. The rate of decrease is gradual and depends on many factors, including rate of production and amount of contaminants allowed to enter the dip tank.

Ring-Oiling

Removing contaminants
Rather than disposing of the entire tank of form release, transfer it to a holding tank and shovel out the sludge. Because the sludge typically contains petroleum hydrocarbons, disposal should be in compliance with local regulations. Then, transfer the recovered form release agent back into the dip tank and top it off with fresh release agent.

Remember that by adding fresh release agent to the recovered material, rather than using all new release agent, reactive levels will be reduced and release problems will occur sooner unless the reactive portion is tested and brought back to a normal level. The discoloration of the recovered material from the dip tank is not relevant to the release characteristics, or levels of reactive material.

Maintaining reactive release levels
Maintaining the correct level of reactive agent in the form release is quite simple. Test the recovered material and bring the reactive portion back to optimum levels.

Test a sample from the dip tank (less than one ounce is sufficient) for the reactive level through either titration or infrared analysis. Your release agent supplier should be able to tell you the optimum level of reactive material required and may be able to run the analysis for you. Once you determine the level of fatty acids, a number of simple calculations determine the amount of pure reactive agent to be added to the dip tank to bring it back to the optimum reactive level.

After adding the recommended amount of reactive material to the dip tank, use an air lance for mixing for a minimum of two minutes, making sure to cover the entire area of the dip tank. Then top off the dip tank with fresh release agent and air lance again for good distribution.

Depending on the amount of contaminants and reduced reactive material, the timeframe between tests will vary. One way to determine the frequency between tests is to establish a baseline. Begin with tests every 30 days, which should be recorded, until a history can be compiled to determine the needed frequency. The normal frequency of adding more reactive ingredients is typically five gallons for every six weeks of regular production.

In many cases, production workers can see the reduced effectiveness of release agents. It’s important to train them to notify management to add additional reactive material to the dip tank. As usual, science is best, but practical application and analysis are also important.

Total replacement of form release
While removing sludge and maintaining dip tanks by adding new release as needed make sense from an environmental and cost perspective, on occasion, you may feel it necessary to clean the entire dip tank to remove all residual sludge and refill the cleaned dip tank with fresh release agent.

Cost-effectiveness
Dip tank maintenance comes down to five options. Option 1 is the least cost-effective, while Option 5 is the most cost-effective.

Option 1: Drain the dip tank, dispose of the sludge and old release material, then refill only with fresh form release agent.
Option 2: Remove the form release from the dip tank, dispose of the sludge, refill the dip tank with fresh form release, then use the recovered form release to replenish the dip tank as necessary.
Option 3: Remove the form release from the dip tank, dispose of the sludge, refill the tank with recovered form release, then top off with fresh form release.
Option 4: Remove the form release from dip tank, dispose of the sludge, test the recovered form release, add reactive ingredient to bring it back to an optimum level, then top off with fresh form release.
Option 5: If there is not enough sludge to remove but the release is not as good as it should be, test for the reactive level of the release agent in the tank, then add reactive material to return it to an optimum level.

In the long run, a little care and attention to the reactive content level in the dip tank will help to reduce labor costs and maintain or improve casting appearance.


Additional news from PRECAST INC

Evaluating and Diagnosing Unformed Surface Imperfections

One Thing: Concrete Consolidation


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 Form Release Agents, Concrete Casting Products, Concrete Casting Supplies, Concrete Pipe, Concrete Safety, Precast Concrete, Grifcote FR 50 Concrete Form Release, Bio Gold Concrete Form Release, Grifcote, Precast Inc Magazine

Preventing Bug Holes in Precast Concrete

Posted by Hill and Griffith Company on Sep 26, 2019 4:40:25 PM

From the June 2, 2014 PRECAST Magazine post Causes and Fixes for SCC Bug Holes, by John Pelicone

bugholes_th.jpgLike a persistent mosquito, one question has plagued precast concrete producers for years: “How can I eliminate bug holes?” In the past, this question was much harder to answer, because concrete was placed at a stiffer consistency that required excessive vibration. And excessive vibration sometimes caused more bug holes. After the introduction of self-consolidating concrete (SCC), bug holes(ii) became a less common occurrence. Yet, as a recent online industry discussion revealed, this perturbing problem is still with us.

"Two types of release agents

  1. Chemically reactive agents: When a chemically reactive form release agent is used, a nonviolent chemical reaction takes place when fatty acids react with free lime on the surface of fresh concrete. This reaction results in the formation of a metallic soap, a slippery material that allows air bubbles to rise along the vertical surface. This “soapy” film also prevents the hardened concrete from adhering to the forms during stripping.
  2. Barrier release agents: Thicker coatings on forms are typical of the older barrier-type materials, like heavyweight used motor oil, vegetable oils, diesel fuel and kerosene. Barrier type release agents are less expensive than chemically reactive agents, but they are not generally recommended for reducing SCC bug holes."

SCC-Bug-Holes-1

Read More

In summary,

"Bug Hole voids are formed during placement. Small pockets of air or water are trapped against the form. The problem increases with the height of the lift. Vibration may not be adequate or well spaced. The mix may be sticky.

  • Primarily caused by the way concrete is placed and compacted
  • Entrapped air not removed by vibration, air bubbles move to the form
  • Improper application of Form Release agent or wrong type 

SOLUTION I PREVENTION: Avoiding Bug Holes

  • Work the voids at the form face up and out of each lift
  • Let the vibrator drop through the lift, then vibrate upward
  • Don't overvibrate at the center of the wall
  • Move the vibrator as close to the form as possible
  • Add upward external vibration if necessary
  • Reduce the height of each lift to make void removal easier
  • Aggregate - consult ready mix producer and review aggregate size and shape
  • Reduce sand content
  • Use low slump concrete"

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 Form Release Agents, Concrete Casting Products, Concrete Casting Supplies, Concrete Safety, Precast Concrete, Grifcote FR 50 Concrete Form Release, Concrete Form Release for Wood, Bio Gold Concrete Form Release, Grifcote, Precast Inc Magazine

The Influence of Form Release Agent Application to the Quality of Concrete Surfaces

Posted by Hill and Griffith Company on Sep 19, 2019 11:00:54 AM

ACI 318-19 was published in response to new engineering practices and industry changes.

Excerpt from a technical paper by A. Klovas and M. Daukšys 2013 IOP Conf. Ser.: Mater. Sci. Eng. 47 012061.

Introduction

High quality surface finishes are a feature of self-compacting concrete (SCC), but by careful attention to mix design and job site workmanship, nice surfaces with the conventional concrete mixture could be achieved. The appearance of an element mainly depends on: the type of cement and addition used; the mix composition; the quality of the concrete mold and release agent; and the placing procedure. If compared self-compacting concrete with the conventional–the color is generally more uniform. Also, it is easier to avoid defects due to leakage spots at the location of mold joints. Blowholes, honeycombing and other blemishes can be found in all types of concrete but with more fluid concrete mixture it is possible to improve the surface finish. International Council for Building Research has provided guidelines how the concrete may be defined referring the surface quality:

  • ROUGH class – no special requirements for finishing
  • ORDINARY – surface finishing has a minor factor
  • ELABORATE – definite requirements for visual appearance
  • SPECIAL – highest standards for appearance
Concrete Form Release Agents Help Form Removal
photo credit: Bob Sawyer

Formworks are also very important factors for concrete surface quality. Scientist, J. Sousa Coutinho, has researched using two different formworks: controlled permeability (CP) and five-layer wood-based formworks. The results have shown that by using CP formworks, the pore diameter (nm) of concrete surface has decreased up to 50%, porosity – up to 45%, surface hardness (MPa) increased up to 70%, and blow-hole ratio has decreased up to 90 % compared with those concrete surfaces using five-layer wood-based formworks.
 
A number of studies determine how to achieve better consolidation resulting in fewer surface blemishes [7-15]. To minimize the size and number of bug holes and all other effects, the following practices should be followed:
  • Vibration period should be of sufficient duration
  • Vibrator insertions should be properly spaced and overlapped and the vibrator removed slowly
  • Each concrete layer should be consolidated from the bottom upward
  • Vibration periods should be increased on withdrawal when using impermeable forms that permit air trapped at the form surface to escape through joints as between
  • Inward sloping forms and other complex design details should be avoided
  • Vibrator should penetrate into the previous layer;

The main outcome of this research is to evaluate the usage of different form release agent applications on the formwork. In addition, this paper presents a technique which provides:

  1. A method how to evaluate the concrete surface quality using image analysis process;
  2. An evaluation of concrete surfaces quality by the following documents: CIB report no. 24 [4] and GOST 13015.0-83.
  3. A combined method how to evaluate and divide concrete surfaces into special categories provided by CIB report no. 24 GOST 13015.0-83 and “ImageJ” in respect to the area of blemishes.

Read More


 

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 Casting Products, Concrete Casting Supplies, Concrete Safety, Precast Concrete, Grifcote FR 50 Concrete Form Release, Concrete Form Release for Wood, Bio Gold Concrete Form Release, Gricote, Concrete Form Release Agent

ACI Releases New Building Code Requirements for Structural Concrete

Posted by Hill and Griffith Company on Sep 12, 2019 4:58:19 PM

ACI 318-19 was published in response to new engineering practices and industry changes.

Article excerpt by Jack Moehle published in the Concrete Contractor August/September 2019 issue.

The American Concrete Institute (ACI) published ACI 318-19: “Building Code Requirements for Structural Concrete in July 2019, in response to new engineering practices and industry changes.

ACI 318 presents requirements for design and construction of structural concrete that are necessary to ensure public health and safety. The document is intended for engineers and building officials, but because it addresses materials advancements and applications, it is expected to have an impact on jobsite procedures. It is anticipated the final code requirements of 318-19 will be referenced in the 2021 International Building Code (IBC).

318_19_cover_highres2.5d39ca6a430aa

New Engineering Practices Translate to Changes in the Field

  • ACI was prompted to make updates in the code due to:
    • new technology (computers used for design and analysis by engineers and architects)
    • increased construction of tall buildings
    • the need for seismic resistance
  • New requirements include:
    • minimum reinforcement on interior column-to-slab connections
    • longer bar lengths for thicker, two-way slabs
    • additional transverse reinforcement
  • Updates include
    • expansion of permissible applications of high-strength reinforcement
    • new requirements for material properties of high-strength steels
    • several changes to strut-and-tie method (STM) for design of discontinuity regions
    • clarity on Anchorage-zone reinforcement

New Materials Addressed

  • IBC shotcrete provisions were included
  • Post-installed concrete screw anchors are now recognized

Alternate Cements and Aggregates

  • Now includes provisions for alternate cements and aggregates
  • No details are readily available for these materials because not enough industry testing is available

Read More


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Selecting and Using Concrete Release Agents - Excerpt

Posted by Hill and Griffith Company on Sep 6, 2019 5:35:38 PM

Enhance the quality and economy of precast products by using the right release agent

Article excerpt by John A. Koski published in the Concrete Construction March 1994 issue.

Almost every precaster has had a double-tee or an architectural precast panel crack as it was being removed from a form. In some cases, an ineffective or improperly applied release agent may have been the culprit. At other times, the wrong type of release agent may have been used. Knowing how to properly use form release agents and which agent should be used for a particular application can go a long way toward preventing costly mistakes. In addition, following proper procedures and using the right agent can enhance the quality and economy of a finished precast piece.

Less is better with Precast Concrete From Release 3

BASICS OF USE

  • Make sure the release agent you are using is compatible with the form or mold it is being used on. For example, some release agents can cause an adverse chemical reaction when used on foam or rubber forms.
  • Don’t purchase a release agent based on price alone. When examining prices of comparable release agents, compare them based on their cost per square foot of coverage, not by the cost of a 5-gallon pail or 55-gallon drum.
  • Protect form release agents from temperature extremes. Release agents that have frozen and then become liquid again may have had their form release properties altered or destroyed. Extremely high temperatures also can damage the properties of release agents. 
  • Thoroughly mix or agitate release agents that require mixing or agitating. This ensures proper dispersion and continuity of the chemical components within the release agent. Always follow manufacturer recommendations when considering mixing or agitating. Some release agents don’t need to be, or shouldn’t be, mixed or agitated.
  • Make sure workers wear respirators, goggles, face shields, gloves, and other protective clothing as required by the manufacturer and government agencies. Make sure workers are properly trained in all aspects of the application process. This includes not only safety concerns, but also how to properly apply the release agent being used. The application technique workers use, however, may not be appropriate for the new product and can cause it to perform unsatisfactorily or not at all.
  • Before applying the release agent, remove any buildups of concrete, rust, scale, or dirt that may be on the forms.
  • Repair any holes, fractures, or other defects in the forms. Just prior to applying a release agent, make sure that the surfaces of the forms are clean and free of water, dust, dirt, or residues that could be transferred to the surface of the concrete or affect the ability of the release agent to function properly.
  • Make sure that forms are coated uniformly with no gaps, sags, runs, or beads. To avoid these problems, never apply a too-heavy coat. Sags, drips, and runs should be removed as recommended by the manufacturer.
  • Make sure spray equipment is working properly. 
  • Do not over-apply a release agent, especially when using a release agent that is chemically reactive.
  • On new wooden forms, thoroughly saturate the forms according to manufacturer directions before placing concrete.
  • It is best not to wait an excessive amount of time after applying the release agent and before placing concrete as dust and other airborne contaminants can form a light coating over the release agent
  • If the concrete is to be painted, plastered, or have other coatings applied, be sure to use a release agent that won’t prevent the coating from bonding with the concrete.
  • Don’t allow release agents to contact reinforcing steel. Doing so can prevent the concrete from bonding to the reinforcement.

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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 Casting Products, Concrete Casting Supplies, Concrete Safety, Precast Concrete, Grifcote FR 50 Concrete Form Release, Concrete Form Release for Wood, Bio Gold Concrete Form Release, Gricote, Concrete Form Release Agent, Concrete Construction Magazine

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