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ACI WEB SESSIONS

The Art of Concrete

ACI Spring 2012 ConventionMarch 18 – 21, Dallas, TX

ACI WEB SESSIONS

Mark J. Bloschock retired from the Texas DOT Bridge Division in 2007, served with the FHWA Office of Safety 2007- 2008 and is currently a consultant to the North Texas Tollway Authority (NTTA) in Dallas, Texas where he has served as a Visual Quality Assurance Team Leader.

THE ART of CONCRETE

Natural Grey Concrete Surfaces

for Visual Quality and Sustainability Mark J. Bloschock P.E.VRX, Inc.

Plano, Texas

Fixin’ To Do List

Background

Visual Quality Program

Lessons Learned

Q&A

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Background

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Coatings

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“TxDOT takes this wonderful,

maintenance-free material called

concrete…

-Dr. John Breen

University of Texasca. 1996

“TxDOT takes this wonderful,

maintenance-free material called

concrete… and then they paint it.”

-Dr. John Breen

University of Texasca. 1996

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North Texas Tollway Authority

Special Specifications 850

Natural Grey Concrete

Visual Quality Program:

Define Goals

ACCEPTABLE RESULTS

KEY WORDS

•Consistent

•Uniform

•Unvaried

•Always the Same

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UNACCEPTABLE RESULTS

KEY WORDS

•Inconsistent

•Varied

•NoticeableDifferences

UNACCEPTABLE RESULTS

KEY WORDS

•Inconsistent

•Varied

•NoticeableDifferences

•Visual defects that draw attention to themselves

Visual Quality Program:

Owner Expectations

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Visual Quality Program:

VQ Defects

VISUAL QUALITY DEFECTS

Efflorescence

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Change in Mix Design

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VQ Defects:

Possible Solutions

Mock-up Samples are required

• as a communication tool

• to demonstrate skills and installation techniques

• to establish expectations

• to measure results

Mock-up Samples

Separate mockups are needed for each class of concrete

Mock-up Panels Required

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Prior to Sand BlastAfter Sand Blast

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Celebrate VQ Successes

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SOLUTION

30 minutes later

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Lessons Learned

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Lessons Learned:Slipformed rail

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Water is your enemy!

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Lessons Learned:Organic Fiber Mockups

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Lessons Learned:Color Gun

Color Gun

• Objective

• Consistent and Accurate

• Precise

• Easy

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Color Quality Control

Color measurement outputs:

CIE L*, a*, b* color values provide a full numerical descriptor of a color standard or sample.

L* represents lightness (White is 100. Middle Gray is 50. Black is 0.)

a* represents redness-greenness (Positive values are red. Negative values are green. Neutral is 0)

b* represents yellowness-blueness (Positive values are yellow. Negative values are blue. Neutral is 0)

Southwest Brown Concrete Sample‐in full sun

Southwest Brown Concrete Sample‐in full shade

Southwest Brown Concrete Sample‐in a dark room

Color Evaluation

Color Range

• Concrete color changes with age

• This can’t be used as an excuse

• All concrete must have the same color at the end of the day

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Mark J. Bloschock P.E.mark.b@vrxglobal.com

Self Consolidating Concrete (SCC) Mockups for the Exchange Parkway Sand Storage Stockpile shown in the order that the mockups were poured

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Mockup forms were stripped after a one‐day cure. Note the small dots of hardened grout splash.

Showing a close‐up view of the same mockup form and a distinctively shaped dot of hardened grout splash. Also Note that the surroundingdots of grout splash have been mirrored on the surfaceof the mockup.  

Showing a close‐up view of the same mockup surface and a mirror image  of the distinctively shaped dot of hardened grout splash 

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The side forms for the same mockup were also inspected. Note that James Hill is pointing to additional distinctively shaped dots of grout splash.

Showing a close‐up view of the side of the same mockup surface and a mirror image of  the distinctively shaped dots of hardened grout splash

Adjacent to the mockup pourat the Coit Road Bridge is the recently stripped mask wall pour. Bug holes were noted on the surface.    

Note the numerous dots of grout splash that mirror the pattern of bug holes on the finished concrete surface.

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