TO: XXXXXMay 3, 2010 Ave. XiverXXXad XXXXX Chihuahua, Chih., Mex. 31320 Tel. (---)---.0525 Fax: (---) ---.0542 email:
PerSite Evaluation 4.27.10
Thefollowing is based off of a site evaluation. Verbal conversations and contractsbetween other parties are unknown and not included in this inspection report(Report (17) pages, Exhibit X (5) pages, Attachment 1 (2) pages, Attachment 2(2) pages).
April 20, 2010Concrete Consulting was contacted about a project in Chihuahua, MX, with jointfailure. Seven days later Ivisited the project for a thorough evaluation and compiled Exhibits A – Xbelow. The project is a concrete tilt up building housing a specialtymanufacturer. The overall building quality was impressive and appeared to beconstructed with advanced excellence. A specialty epoxy / urethane concrete coating system was specified whichappeared to be installed properly and professionally. The concrete slabconstruction was flat, all lines were true and cracking was nominal. Allrequested documents from xxxxxxxxxxxxx were supplied in detail and in a timelymanor. Typicalconcrete slabs have their own unique chemistry, character and profile ofperformance. It is this variance in concrete formulation, placement, finishing,curing, profiling and subsoil conditions that makes predictability of coatingsand adhesion very elusive. This Chihuahua project has a character that isunique and currently hostile due to the trapped moisture. Water is purging vertically in the majority ofconstruction and control joints. This water and vapor caused mass failure atthe joint to slab bond line interface (Exhibit H).
OverallProject. Overall Epoxy / Urethane horizontal system (15 – 20 mils thick) performswell. The joint system has failedeverywhere. ProjectsExterior. The exterior project profile is dry and subterranean soil waterinfiltration caused from surrounding mediums is not a factor. Scratch Adhesion Test. Test shows there is a qualitybond to the horizontal surface substrate. Joint SlabCore. Core shows a perfectly installed control joint. The backer rod, depthsand product installation were good. Joint construction is not a factor. Under Coating PH Test. Slab PH tests were high. Thiselevated reading is caused from the trapped slab moisture percolating to thesurface. As the concrete vaporpercolates to the surface it increases the PH levels at the bond line. The elevated PH levels are not affectingthe coating but could be one of the factors at the joint slab bond line. Surface Color. Here the color of the slab is abnormallydark in color. This shows the slab has trapped moisture. This is a serious factor causing jointfailure. 3 Calcium Chloride Tests. All CC tests were high and is anotherfact showing the hostile slab environment caused by trapped moisture. Thispressure is a factor causing joint failure. JointMoisture Damage. The epoxy horizontal slab is has sealed the surface so wellthat the moisture is taking the path of least resistance purging and damagingthe joints. Joint PH.The PH levels in the joints were not of hostile concentration and are not afactor in joint failure. Soil SurfaceMoisture. The surface of the soil was moist. This moisture shows there istrapped moisture between the slab and tack cote (Vapor barrier). This is afactor in the joint failure. Core SlabWater. Water drips off of the blade as it penetrates the vapor barrier. Failurefactor.
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Joint Water. This shows the purging of trappedmoisture. Slab pressures are spewing the excessive moisture through jointscausing failure. ElectricalImpedance Meter. Shows a direction of high water vapor levels. Surface Texture. This is caused by excessive moisture.After the 60 day breathing of the joints these areas need to be re-prepped andcoated with full system. Cut allexisting joints and let breath for 60 days. After 60 days of moisture purginginstall Sikadur 51 and recoat with Propoxy and Urethane System. Concrete supplier mix letter. It is assumed theconcrete was between .40 to .50 water to cement ratio. Overwatered concretewill create larger slab capillaries allowing excessive vapor transmission and lowsurface strengths. This does notappear to be a factor. Soilmoisture tests. Moisture percentages are low. Not a negative factor. 1 of 3 Calcium Chloride testresults10.69lbs. 3 lbs of pressure is desired. Additionaldatum showed by the high lbs. that there is moisture trapped within theconcrete slab. 2 of 3Calcium Chloride test results9.73lbs.High pressure. 3 of 3Calcium Chloride test results13.59lbs.Extremely high pressure. CalciumChloride test calculations. Slab /Joint Details. Arrows show the location of trapped moisture. In theory this isthe problem with the slab. This is the moisture that needs to be dealt withinthe project solution. A7.2A Plan– Construction Document. C2.2 Plan– Construction Document. PourSequence. Performance coating time line. Understanding Concrete Moisture Document: We havecompiled this data to assist readers understand the complexity of concretemoisture directly associated with this project.
Excessivemoisture is apparent within the slab. The only way to repair it while thetenant is occupying the facility is to let the slab breath through opening theconstruction and control joints. Opening these joints will allow for the excessive moisture to percolateand evaporate naturally. After allowing the joints to breath for 60 daysre-prep the joints and seal. The joints need to be re-sealed with non-ridged (anystandard) 2-component sealant such as Sikadur 51 ns (Attachment 1). Theprevious EUCO 700 (Attachment 2) is not an expansion joint sealant. All theexisting joints are currently vertically and horizontally moving making themexpansion joints. The only downfall of using a non-ridged joint filler will bea small hairline crack in the Propoxy as it is used and worn. Not to worry, the joint is sealed andshould not allow moisture contamination.
ACI Manual of Concrete Inspectionsp-2(07), Quality Sealants, Inc. Christiaan Zaayer (President), Concrete IntʼlAugust 2003, , ACI302.1R, American Concrete Institute, Farmington Hills, MI., ASTM Standards E 1907, F 1869, D4263, F 2170, ASTM International, West Conshohocken, PA, www.astm.org., BruceSuprenant,,Concrete Construction, November 1997, BruceSuprenant,, Concrete International, Vol. 25, No. 3, April 2003, www.concrete.org, Thomas K. Butt, , The ConstructionSpecifier, December, 1992, MalcolmRode and Doug Wendler, ,Concrete Repair Bulletin, March-April, 1996, Steven H. Kosmatka, Portland Cement Association, Skokie,IL, www.cement.org, American Concrete Institute Concrete Repair Bulletin Jan/Feb 2006,Many of the concepts presented in this report may be explored in more detail inthe book by Howard -- M. Kanare entitled “Concrete Floors and Moisture”. It isavailable through thePortland Cement Association. 847-966-6200
Sincerely; ConcreteConsulting.com
Phon Phon888.661.6264
Fa760.760.888.4949
E-Mail Address: Jon Hoffman – jon@concreteconsulting.com
Exhibit A
Exhibit B
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E-Mail Address: Jon Hoffman – jon@concreteconsulting.com
Exhibit C
Exhibit D
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Exhibit E
Exhibit F
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Exhibit G
Exhibit H
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E-Mail Address: Jon Hoffman – jon@concreteconsulting.com
Exhibit I
Exhibit J
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E-Mail Address: Jon Hoffman – jon@concreteconsulting.com
Exhibit K
Exhibit L
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Exhibit M
Exhibit N
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