Post on 07-Feb-2022
Nondestructive Pavement Nondestructive Pavement Thickness Measurement Thickness Measurement
Jagan Gudimettla, P. E.Jagan Gudimettla, P. E. FHWA Mobile Concrete LaboratoryFHWA Mobile Concrete Laboratory
Presentation OutlinePresentation Outline
Introduction / BackgroundIntroduction / Background
MCL Experience with MIT Scan T2MCL Experience with MIT Scan T2
Current Work with MIT Scan T2 TargetsCurrent Work with MIT Scan T2 Targets
Cost ComparisonCost Comparison
SummarySummary
MIT ScanMIT Scan--T2T2
MIT ScanMIT Scan--T2T2
Introduction / BackgroundIntroduction / Background
Operating Principle Operating Principle
How to use MIT Scan T2How to use MIT Scan T2
Memory ManagementMemory Management
Charging and Operating TimeCharging and Operating Time
Maximum Depth MeasurementMaximum Depth Measurement
LimitationsLimitations
MIT ScanMIT Scan--T2T2
MIT ScanMIT Scan--T2T2
AccuracyAccuracy
Specified: Specified: ++ 0.5% of the measured depth 0.5% of the measured depth + 3/64 in (1 mm)+ 3/64 in (1 mm)
Translates to 0.1 in (less than 3 mm) for Translates to 0.1 in (less than 3 mm) for 13 in pavement13 in pavement
Metal TargetsMetal Targets
Size and Shape requirementSize and Shape requirement
Metal TypeMetal Type
CostCost
Metal Target DiscsMetal Target Discs
Metal Target DiscsMetal Target Discs
Target ID Maximum Depth, in
AL RO 12 7.0 in
AL RO 30 13.8 in
ST RO 07 4.7 in
ST RO 12 7.0 in
ST RO 30 13.8 in
MCL Field Visit to Washington StateMCL Field Visit to Washington State
MCL Field Visit to Washington StateMCL Field Visit to Washington State
MCL Field Visit to Washington StateMCL Field Visit to Washington State
Core Difference (in)
Difference(mm)
1 0.062 0.062 1.6
2 0.0820.082 2.1
3 0.0430.043 1.1
4 0.047 0.047 1.2
5 0.165 0.165 4.2
6 0.0270.027 0.7
MCL Field Visit to ArizonaMCL Field Visit to ArizonaMIT T2 Results AZ DOT Cores
Test # Thickness, in Test # Thickness, in
1 15.1 1 15.32
2 15.0 2 15.11
3 15.8 3 14.98
4 15.7 4 15.8
5 15.5 5 15.72
Average 15.42 6 15.28
7 15.42
8 15.63
9 15.07
10 15.39
Average 15.37
FHWA Work with TargetsFHWA Work with Targets
Measuring MechanismMeasuring Mechanism
Effect of NailsEffect of Nails
No nails 3 Nails Halfway 3 NailsAll the way
Difference, in 0.003 0.011 0.011
1 Nail 2 Nails 3 Nails 4 Nails
Difference, in 0.007 0.007 0.007 0.023
Target OptionsTarget Options
ShapesShapes
Thickness Thickness
OrientationOrientation
Typical Thickness SpecificationTypical Thickness Specification
Lot – 2000 sq.yd – 1 core from each lot
→ one core every 1500 ft
→ 4 cores / lane mile
Typical Thickness SpecificationsTypical Thickness SpecificationsPayment Schedule
Thickness Index Range English (Metric) Percent Payment
0.00 or more (0.00 or more) 103
-0.01 to -0.05 (-0.01 to -1.27) 102
--0.06 to 0.06 to --0.10 (0.10 (--1.28 to 1.28 to --2.54)2.54) 101101
-0.11 to -0.15 (-2.55 to -3.81) 100
--0.16 to 0.16 to --0.20 (0.20 (--3.82 to 3.82 to --5.08)5.08) 9999
-0.21 to -0.25 (-5.09 to -6.35) 98
Estimate for Coring/Depth CheckEstimate for Coring/Depth Check
Contractor / DOT CostsContractor / DOT Costs→→
TruckTruck→→
Core drillCore drill→→
Drill bitsDrill bits→→
Staff time for the drillingStaff time for the drilling→→
Staff time to deliver coresStaff time to deliver cores→→
Staff time for patchingStaff time for patching
DOT CostsDOT Costs→→
Staff time to determine and mark core locationsStaff time to determine and mark core locations→→
Staff to observe the drilling and take possession Staff to observe the drilling and take possession of the coresof the cores
→→
Staff time to make and record the measurementStaff time to make and record the measurement→→
Staff time for the independent assuranceStaff time for the independent assurance
$ 90 - 110 / Core
Estimate for using MIT Scan T2Estimate for using MIT Scan T2
Contractor CostsContractor Costs→→
Staff time for taking MIT Scan T2 Staff time for taking MIT Scan T2 measurementsmeasurements
DOT CostsDOT Costs→→
Staff time for placing TargetsStaff time for placing Targets→→
Staff to observe taking MIT Scan T2 Staff to observe taking MIT Scan T2 measurementsmeasurements
→→
Staff time for the independent assuranceStaff time for the independent assurance
→→
Verification Core Verification Core –– 1 Core for every 10 Targets1 Core for every 10 Targets→→
Target Cost Target Cost -- $2 $2
-- 10 10 MinutesMinutes
-- 10 10 MinutesMinutes
-- 10 10 MinutesMinutes
Cost ComparisonCost Comparison
Assume $30/hr laborAssume $30/hr laborlabor $15labor $15Target $2Target $2Core $10Core $10Total Total $27$27
Per lane mile 4 cores requiredPer lane mile 4 cores required
SavingsSavings
$73 / location $73 / location OR OR
$292 / lane mile$292 / lane mile
SummarySummary
Easy to UseEasy to Use
NonNon--DestructiveDestructive
ExpedientExpedient
Cost EffectiveCost Effective
ContactsContacts
Interested in MIT Scan T2 Interested in MIT Scan T2
Contact either:Contact either:–– CPTP ProgramCPTP Program
Sam Tyson (202) 366 1326Sam Tyson (202) 366 1326
Shiraz Tayabji (410) 997 9020Shiraz Tayabji (410) 997 9020
–– Mobile Concrete LaboratoryMobile Concrete Laboratory
Gary Crawford (202) 366Gary Crawford (202) 366--12861286
Jim Grove (202) 366Jim Grove (202) 366--66066606
Jagan Gudimettla (202) 366Jagan Gudimettla (202) 366--13351335
Questions ???Questions ???