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Concrete Casting News from the Hill and Griffith Company

Article Review: Concrete Formed Surface Classifications & Specifications

Posted by Hill and Griffith Company on Jul 18, 2019 1:06:30 PM

Details on classifications & specifications for surface finishes

An excerpt from the July/August 2019 issue of Precast Inc., by Eric Carleton, P.E., NPCA's director of codes and standards.

Evaluating_and_Diagnosing_Concrete_Formed_Surface_Imperfections

Less is better when spraying concrete form release agents on concrete forms.

In 1975, the International Council for Building Research established a general classification of formed surfaces which is referenced in the most recent edition of ACI 301.2R, "Identification and Control of Visible Effects of Consolidation on Formed Concrete Surfaces."

Those classifications are:

  1. Rough - No special requirements for finishing
  2. Ordinary - surface finishing has a minor factor
  3. Elaborate - definite requirements for visual appearance
  4. Special - highest standards for appearance [considered architectural]

Within ACI 347R-14, "Guide to Formwork for Concrete," there is a similar class system to differentiate concrete surface evaluation based on application:

  1. Class D - minimum quality requirement for surfaces where roughness is not objectionable, usually applied where surfaces will be permanently concealed.
  2. Class C - general standard for permanently exposed surfaces where other finishes are not specified
  3. Class B - intended for coarse-textured, concrete form surfaces intended to receive plaster, stucco or wainscoting
  4. Class A - suggested for surfaces prominently exposed to public view where appearance is of special importance

ACI 301-16, "Specifications for Structural Concrete," provides more detailed information.

5.3.3.3(a) Surface finish-1.0 (SF-1.0):

  • No formwork facing material is specified
  • Patch voids larger than 1-1/2-inch wide or 1/2-inch deep
  • Remove projections larger than 1 inch
  • Tie holes need not be patched
  • Surface tolerance Class D as specified in ACI 117-10, "Specification for Tolerances for Concrete Construction and Materials and Commentary."
  • Mockup not required

5.3.3.3(b) Surface finish-2.0 (SF-2.0):

  • Patch voids larger than 3/4-inch wide or 1/2-inch deep
  • Remove projections larger than 1/4 inch
  • Patch Tie holes
  • Surface tolerance Class B as specified in ACI 117
  • Unless otherwise specified, provide mockup of concrete surface appearance and texture

5.3.3.3(c) Surface finish-3.0 (SF-3.0):

  • Patch voids larger than 3/4-inch wide or 1/2-inch deep
  • Remove projections larger than 1/8 inch
  • Patch Tie holes
  • Surface tolerance Class A as specified in ACI 117
  • Provide mockup of concrete surface appearance and texture

5.3.3.5 Unspecified as - cast-finishes - if a surface finish is not specified, provide the following finishes:

  • SF-1.0 on concrete surfaces not exposed to view
  • SF-2.0 on concrete surfaces exposed to view

For the full article, please visit the Precast.org 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.

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 Bulletins and Technical Papers for Concrete Casting Products

Tags: Concrete Casting Products, Concrete Release Agents, Concrete Casting Supplies, Precast Concrete, Gricote, Precast Inc Magazine

Article Review: Evaluating and Diagnosing Formed Surface Imperfections

Posted by Hill and Griffith Company on Jul 11, 2019 4:18:57 PM

Precast formed concrete surface problems and how to identify and correct them

An excerpt from of the article found in the July/August 2019 issue of Precast Inc., by Eric Carleton, P.E., NPCA's director of codes and standards.

Evaluating_and_Diagnosing_Concrete_Formed_Surface_Imperfections

Less is better when spraying concrete form release agents on concrete forms.

Green Bay Packers Coach Vince Lombardi said, “Perfection is not attainable, but if we chase perfection, we can catch excellence.” Precast manufacturers try to make perfect products, but like most things, attaining complete perfection is elusive if not impossible. While the goal is to attain perfection, precasters recognize the economic and production realities that some product irregularities will occur. The goal is to mitigate imperfections while still maintaining tolerances and meeting owners’ expectations.

For (precast) formed concrete surfaces, many problems can be narrowed down to three practices: consolidation or vibration, form set up and maintenance, and form oil/release agent application.

Common issues:

  1. Bugholes
    1. Poor or improper concrete consolidation
    2. Excessive application of form release oil or agent
  2. Honeycombing
  3. Cracking
  4. Fins
  5. Form Bleed
  6. Poor Form Fit
  7. Sand Streaking
  8. Layering Marks
  9. Cold Joint
  10. Staining
  11. Color Continuity

Regardless of the end use, a well-cast product, free of formed surface irregularities, provides an excellent representation of a quality operation.

For the full article, please visit the Precast.org 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 Casting Products, Concrete Release Agents, Concrete Casting Supplies, Precast Concrete, Gricote, Precast Inc Magazine

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