ology and Codes

The Condition Survand Evaluation of Hardened Concret

Concrete Techno
Evaluation Technique

z Condition Surveyz Nondestructive Testingz A l ti l M th d Analytical M

eth

o

d

s

z Destructive Testing
Resources

z ACI 349.3 R- Evaluation of Existing Nu

Safety-Related Concrete Structures

z ACI 364.1 R- Guide for Evaluation of 

Concrete Structures Prior to Concrete Structures Prior to

Rehabilitation 

 Table 6.1a and Table 6.1b
Purpose of Investigatio

z Property Assessmentz Determine Future Serviceabz Conform with Construction 

Specifications

z Obtain Data for Litigationz Evaluate Performance of Comz Establish Methods for Repai

Replacement
Scope of 

Investigation

z Limited to Isolated 

Areas of Distress

z Entire Structure
Prioritization

z Safety Sigz Location/

Acces

z Ex

posure 

Condition
Frequency
Qualifications of Inspecto

z Responsible in-charge:

 P.E., or civil or structural engine

years experience

z Personnel performing inspection

 Civil or structural engineer w/ m

year experience; or personnel wyears experience
Condition Survey

z Visual Observationsz Speak to Construction Per

Determine Extent of Pro

z Recordsz Do Not Overlook Detailsz Most Problems Are a 

Combination
z When troubleshooting 

concrete problems it is important to relate the sy p m tom to causes of diand deterioration.
Identify Concrete Sur y Concrete Surface 

Defects

z Blisters Az Delaminations z Crazingz Crackingz Honeycombingz Dil i sco orationz Efflorescencez Dustingz Popoutsz Mortar Flaking & Scalingz Spallingz Corrosion
Field Kit Essentials z Camera, Film

z Flashlightz Tape Measurez Crack Comparatz Hammer, Chiselz Sample Bagsz Marking Penz Chalkz Thermometerz Compass
Another Helpful Tool....

Contributed by: M. Thomas

Visual

z Use All Your Sen

TouchSeeSmellHearTaste

z Look For the Obz Use Common Sez Don’t Jump to 

Conclusions!!!
Interviews

z Contractorsz Engineersz Inspectorsz Tradesmenz Suppliersz Ownersz Occupants
Review Reports and

Documents

z Project Spez Contract Dz Shop Drawz Submittalsz Change Ord

Change Ord

z Field Repor
Document Field Observ

z Condition of Exposed Surface

Popouts, Discoloration, etc.

z Nature and Extent of Crackinz Secondary Depositsz Evidence of Building Moveme

Volume Changes, Deflection, Settlement, etc.

z Previous Repair Work Perform
Rate Level of Distress

z Scaling

 Light-

• Loss of surface mortar wi

exposure of coarse aggre

 Medium

-

• Loss of surface mortar up 

mm (0.2-0.4 in.) in depth exposure of coarse aggre
Rate Level of Distress

z Scaling

 Severe-

• Loss of surface mortar up to 5-10 m

0.4 in.) in depth with some loss of surrounding aggregate particles 10

(0 4. -0 8 in ) in depth so that aggre

0.8 in.) in depth, so that aggre

clearly exposed and stands out froconcrete.

 Very Severe

• Loss of coarse aggregate particles 

surface mortar and surrounding aggenerally to a depth of greater tha(0.8 in.)

Rate Level of Distress

z Spalling

 Small-

• Not greater than 20mm (0.

depth nor greater than 150in.) in any dimension.

 Large-

• Deeper than 20mm (0.8 in.

greater than 150mm (6 in.) dimension.
Observations on Cracki

z Surface Appearancez Depth & Width of Crackingz Current State of Activityz Physical State of Concrete W

Physical State of Concrete W

Crack Occurred

z Structural Nature of the Crac
Surface Appearance

z Pattern Cracks

 map cracks, cra

checking, D-cra

z Individual Cracks 

 diagonal, longit

transverse, verhorizontal
Depth of Cracking

z Depth-

 Surface, Shallow, Deep, Through
Width of Cracking

z Width-

 Fine

generally le

mm (0.04 

 Medium

bt 1 e

tween 

1

-

(0.04-.08 

 Wide 

over 2 mm 

(0.08 in.) 
Current State of Activity

z Activez Dormant
Physical State of Concre

When Cracking Occurre

z Before Hardenin

 Plastic

ShrinkageSettlement

 Construction M

Formwork MoSubgrade Mov
Physical State of Concre

When Cracking Occurre

z After Hardening

 Physical

Drying ShrinkageCrazing

 Chemical

Corrosion of ReinfoAlkali-Aggregate Re

 Thermal

Thermal ContractionFreeze-Thaw Cycles
Physical State of Concre

When Cracking Occurre

z After Hardening

 Structural

Accidental OveCreepDesign Loads

Nondestructive Te

ACI 22
NDT Evaluation of Conc

z To determine soundness or integriz Strengthz Locate voids, delaminations, crackz Locate reinforcing steel or dowelsz Locate contaminationz D t i thi k D

e

termine thi

c

kness

z Bond strength, strength developm
Nondestructive Evaluatio

Methods

Property Recommended 

Methods 

PM

Strength Penetration Probe 

Rebound Hammer Pullout Methods 

Pulse 

Rebar Size and Rebar Size and Covermeter

X ray 

Location 

Covermeter

(Pachometer) Gamma Radiography 

X

-ray 

UltrasEcho R

Presence of Subsurface Voids

Acoustic Impact Gamma Radiography Ultrasonic Pulse Velocity 

ThermX-Ray UltrasEcho 
Pachometer Pachometer (covermeter covermeter

z Assesses- Location of Embedded Meta
Soundness Testing

z Hammers, Steel 

Chain Dragging

z Used to Assess

 Delaminations Voids
Reliability of NDT?
Analytical Method

Strength Evaluation of 

Structures

z Safety/structural integrz Low cylinder strength rez Strength Evaluation:

 Analytical Investiga Load Tests
Analytical Investigatio

z Perform Field Investigatio

Dimensions and Details of Members, Properties of M il ater

als, etc.

z Perform Analysis to Deter

Structural Integrity

 Hand Calculations Computer Analysis
Load Testing
Monitor

z Deflections
Destructive Testing
Sampling Plan

z ASTM C823- Standard Practice fo

Examination and Sampling of Hardened Concrete in Constructi

z Good vs. Badz Sample Location Sample Location

-

Strategic Random Sampling

z Is Coring Necessary??

Sampling Procedures

ASTM C 42

z Coringz Sawing
Drilling
Sledges, Chisels, etc. 

Should Not Be Permitted
Sample Identification

z Document z Chain of Cz Field Notez Photograp
Sample P

z Mark Locat

With Paint

z Keep Samp

Intact
Core Length
Correction Factor

z Ratio of Length to 

Diameter (L/D)

1.751.50

z Strength Cor

Factor

0.90.9

1.251.00

0.90.8

If a Core Has a Max. Length < Diameter Prior To Capping Diameter Prior To Capping- It M

It M

Included in Test Results
Full Length Cores
Always Evaluate Interio

of Core Hole
What If Core Breaks 

During Removal?
Document Co

Observations Field

Including:zCore DimensiozHole DepthzAggregate SizezReinforcement zVisible CrackingzVoids, RubblezDelaminations
Contributed by: M. Thomas
Transportation of 

Samples

z Identify By Orientation and 

 Top and Bottom 

z Protect By Wrapping and S

 Bubblewrap 

z Pack and Deliver in Safe En

 Cooler
Laboratory Testing

z Visual Assessmentz Strengthz Modulusz Pulse Velocityz Absorption, Densityz Petrographic Analyz Air-Void System (AVz Permeabilityz Chemical Analysisz Expansion Testingz & Many Others
Chemical Analysis

z Chemical Comz X-Ray Diffractioz Thermal Analyz Acid/Base Indi
Petrographic Examinati

ASTM C8z Cemenz Aggregz Cracksz Voidsz Second

Deposi
Evaluation Procedure Evaluation Procedure- ACI 364.1 

ACI 364.1 

Petrographic Analysis

To Test Concrete For: (Table 6.1a)

z Acidityz Air Contentz Alkali-Carbonate Reaction

z Frozen Componenz Permeabilityz Quality of Aggreg

z Alkali-Silica Reactionz Cement Contentz Chemical Compositionz Chloride Contentz Contaminated Aggregatez Contaminated Mixing Water

z Freeze/Thaw Resiz Soundnessz Sulfate Resistancez Uniformityz W/C
Evaluation Procedure Evaluation Procedure- ACI 364.1 

ACI 364.1 

Petrographic Analysis

To Test Concrete For: (Table 6.1b)

z Bleeding Channelsz Chemical Deteriorationz Corrosion of Steel

z Erosionz Freeze/Thaw Damz Honeycombing

z Crackingz Delaminationz Discolorationz Disintegrationz Efflorescence

z Uniformity of Con
Testing

z Samples Should Be Suffici

Size and Number To PermApplication of All NecessaLb T a oratory Tests

z Once Samples are Obtaine

Certain Samples Should BSelected And Submitted FTesting Without Bias
Summary of Evaluation
Summary

To Effectively Evaluate a ConcStructure All Of These Steps PRole:zVisual ObservationszNDTzAnalytical MethodszCreating a Concrete Sampling PlazDocumenting Field Sampling Proc