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Jonathan Meier

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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.

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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 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."
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 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

Why Precast Concrete Cistern pH is Important

Posted by Jonathan Meier on Jul 12, 2018 5:58:17 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

• Is a Rainwater Cistern Right for You?

Second U.S. "Living Building Challenge" Home Certified

• How I Ended Up Living Off the Grid in New Mexico


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 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

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