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Work Plan: Original and Proposed

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by

Agustin Spalvier

on 12 September 2013

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Transcript of Work Plan: Original and Proposed

Evaluation of PCC Pavement and Structure Coring and In-Situ Testing Alternatives
General Objectives
1 - Understand the effect of:
NDT
Three NDT techniques are proposed
Conditions affecting Strength Measurement Estimations from Cores
Sample size
Original Plan
Slab dimensions: 60 in x 60 in x
13 in
2 - Evaluate the utility of practical non-destructive testing methods for estimating in-place concrete strength
Presence of embedded rebar
Inherent damage from coring
Age at testing
Moisture core conditioning
14 slabs will be cast
8 in-place cylinders and 8 cores will be extracted from each slab
Three companion cylinders per slab will be cast
Summary of Extractions
Achieving Specific Objectives
3 Different Mixtures
PV
: Pavement concrete
SI
: Structures concrete
Low-SI
: Low-strength concrete
2 Moisture Core Conditioning Cases
1-day dry
: Core stays for 1 day being dried until tested
(tested on day 16th)
5-day bag
: Core stays for 5 days inside a impermeable bag until tested
(tested on day 20th)
Rebar Presence
Two slabs have embedded rebar
Core diameter:
4 in
In-place cylinder diameter:
6 in
Expected Results
Measure the combined
"Coring Damage & Size Condition"
effect
, for 1-day dry Moisture Condition
Measure the combined
"Coring Damage & Size Condition"
effect
, for 5-day bag Moisture Condition
Measure the combined
"Rebar & Size Condition"
effect
, for 1-day dry Moisture Condition
University of Illinois at Urbana-Champaign
Revised Plan - Changes
Expected Results
Measure the
Coring Damage
effect
, for 1-day dry Moisture Condition, at Age 16 days, in relation to the corresponding In-Place cylinders
Measure the combined
Coring Damage
effect
, for 5-day bag Moisture Condition at Age 20 days in relation to the corresponding In-Place Cylinders
Measure the combined
Rebar
effect
, for 1-day dry Moisture Condition, at age 16 days, in relation to corresponding In-Place Cylinders
Comparative Table
Original
Proposed
Benefit
Core diameter
4 in
In-Place Cylinder diameter
6 in
Cores and Cylinders have the same size so the Damage effect may be studied separately from the size effects
Slabs thickness
4 in
4 in
13 in
9 in
Less concrete to cast and easier manipulation: Less $$$
Extraction Plan
No bias due to extractions' location
Steel bars do not intercept in-place cylinders
Ultrasonic Surface Waves
Nitto Hammer
Mechanical Impedance
CAPO Test
Presentation Outline
Overall procedure:
Extract cores and in-place cylinders from slabs
Test and calculate compressive strength following ASTM C39
Compare core strength to in-place cylinder strength
Original extractions distribution in slab:
Testing details:
Equal to SI mixture but with w/c and air content above specified:
w/c = 0.5
air cont = 8-9% (vol)
Original Extraction Plan
Our specific objectives?
1-day dry
Cores
In-Place Cylinder
5-day bag
Cores
In-Place Cylinder
Analysis
Slab Cast
Concrete age (days):
0
Cores
1dd
In-place cyl
Cores Extraction
15
16
1dd
In-Place Cylinder Extraction and Tests
Cores
5db
In-place cyl
5db
20
In-Place Cylinder Extraction and Tests
Which data can we compare ?
Time-line
Data
Can the
be improved?
Revise Plan!
In-place cylinder diameter:
1-
Originally
6 in
Revised
4 in
Why?
To separate Size Effect from Coring Damage effect, and have more accurate results
2-
Slabs' thickness
Originally
13 in
Revised
9 in
Why?
As in-place cylinder diameters are reduced, thickness can be reduced as well
Easier handling
Less material, thus less $$$
3-
Extraction distribution in slab
Original plan
Revised plan
Why?
Reduces bias in results due to extractions' location
Considers the slab with embedded rebar
To make the
in-place cylinder
size
=
to the
core
size
Concrete Model
Schematic of hammer sensor response
Active side
Reactive side
Wave speed and amplitude measurements may estimate concrete's compressive strength
Output parameters to estimate concrete's compressive strength:
Active Impedance - Reactive Impedance - Strength
Principle: pullout a small piece of the member's surface. The measured pullout force is related to the concrete's compressive strength.
Equipment and Training ?
Germann Instruments would provide equipment
GI requires the operator/s to take a one-day training course
Strength at age 16 days
Strength at age 20 days
Which properties will be estimated ?
Data analysis ?
Data Analysis
Statistical analysis carried out by University of Southern Indiana
Comma delimited data
Files shared by Dropbox
T-test analysis
MiniTab
Approximate Timeline
Objectives
Factors affecting compressive strength
Original Plan
Revised Plan - Changes
NDT
Data analysis
Approximate timeline
September 12th, 2013:
END of the presentation
Thank you!
John S. Popovics, Agustin Spalvier and Kerry Hall
University of Illinois at Urbana-Champaign - University of Southern Indiana
Core sample condition, and
Core sample conditioning procedures
in order to estimate in-place concrete compressive strength
Two different rebar locations:
Inner third of the core
Outer two-thirds of the core
1-day dry
Cores Rebar
(Semi-Destructive Test)
Full transcript