PSMC 005 – SH 016 Glorit Hall

PSMC 005 – SH 016
Glorit Hall
Pavement Condition
Shoving in pavement
1
Pavement Condition
Rutting and Cracking in pavement
Pavement Configuration
150 mm cement modified aggregate
E = 400 MPa (non-cracked pavement)
100 mm Unbound aggregate
E = 50 MPa
Infinite depth of subgrade
E = 30 MPa
2
Basecourse Properties with 33%
GAP 65
Cement Response
Test
UCS (MPa)
4% Cement
1.3
5% Cement
1.6
6% Cement
3.0
Design Pavement Configuration
Used by Beca
180 mm Cemented basecourse layer, E = 2000 MPa
Cement content was 7% and depth of stabilisation was
230 mm to allow for site mixing and material variability
(Site mixing 50 mm greater than design depth)
100 mm Unbound sub-base
E = 50 MPa
Infinite depth of subgrade
E = 30 MPa
3
Beca Design Philosophy
Aggregate at the crack interface will
provide lasting load transfer if it is held in
a strong matrix
Construction
Finished product
4
Post Construction Analysis
04/06/2004
Pavement Depth
(mm)
10th percentile
Modulus (MPa)
200
2190
150
385
Infinite
99
Post Construction Analysis
11/02/05
Pavement Depth
(mm)
10th percentile
Modulus (MPa)
230
2135
50
184
Infinite
109
5
PSMC 005 – SH 01N
Poplar Hill
Crawler Lane Condition
Cracking & rutting in pavement
6
Basecourse Soaked CBR
Additive
Nil
CBR (%)
30 & 60
3% Lime
55
2% Cement
150 & 220
3% Cement
140 & 265+
Crawler Lane Pavement Design
35 mm, OGPA over chip seal,
E = 800 - 1000 MPa
200 mm, 40 mm top size, FBS, 3.5%
bit., 2% filler, E = 800
200 mm, 40 & 65 mm top size, fine
graded, slightly plastic, E = 150 MPa
Infinite depth of clay subgrade
E = 50 MPa
7
Post Construction Analysis
27/10/2004
Pavement Layers (mm)
10th percentile
Modulus (MPa)
200 FBS basecourse
626
200 unbound aggregate
448
Infinite subgrade
41
Post Construction Analysis
18/02/05
Pavement Layers (mm)
10th percentile
Modulus (MPa)
200 FBS basecourse
2222
200 unbound aggregate
354
Infinite subgrade
51
8
Post Construction Analysis
15/06/2006
Pavement Layers (mm)
10th percentile
Modulus (MPa)
50 OGP + levelling
3895
200 FBS basecourse
2144
200 unbound aggregate
245
Infinite subgrade
66
Hewletts Road
Pavement Design
9
Pavement Configuration Options
Thin
surfaced flexible )TSF)
Modified TSF
Cemented treated sub-base
(CTSB)
Structural asphaltic concrete (SAC)
Portland cement concrete (PCC)
Modified TSF Pavements
The aggregate layers can be modified
with small amounts of chemical
additive to increase stiffness and shear
strength to reduce rutting with the
aggregate layers
Usually about 2% - 2.5% cement used
with < 1.5 MPa UCS
10
Modified TSF Pavement
Traffic loading 3 x 107 ESA’s
Basecourse and upper S/B modified with
2.5% cement
35 – 40 mm of SMA
E= 1500 MPa
150 mm basecourse
E = 500 MPa
300 mm sub-base
E = 130/250 MPa
Subgrade CBR = 10%
E = 70 MPa
CTSB Pavement – Post Cracked
Load causes horizontal tensile strain at the
bottom of the bound layer which cracks
quickly unless uneconomically thick
(AUSTROADS requires ESA’s x 20 plus
conservative fatigue criteria)
CTSB layer retains high modulus postcracked and subgrade strain criteria rules
(AUSTROADS = 500 MPa, actual = 2000
MPa)
AUSTROADS requires 230 mm
basecourse to stop reflective cracking
(100 mm works in practice).
11
CTSB Pavement - Cracked
Traffic loading 3 x 107 ESA’s
S/B treated with 5-6% cement (UCS > 3.0
MPa)
35 – 40 mm of SMA
E= 1500 MPa
100 mm basecourse
E = 500 MPa
Subgrade CBR = 7%
E = 70 MPa,
200mm cracked CTSB
(180 mm GAP 65 + 50
mm sand subgrade)
E = 1000 MPa
Possible CTSB Pavement – Non-cracked
Traffic loading 3 x 107 ESA’s
S/B treated with 5-6% cement (UCS > 3.0
MPa). Designed NOT to crack for design life.
35 – 40 mm of SMA
E= 1500 MPa
30 mm OGPA
E = 1000 MPa
Subgrade CBR = 7%
E = 70 MPa,
340mm CTSB (230
mm GAP 65 + 110
mm sand subgrade)
E = 5000 MPa
12
Examples of CTSB Pavements
Site
Loading
Pavement Profile
Date
Comments
Macandrew
Rd, Dunedin
Kirkcaldy to
Forbury
4,200 vpd
2% HCV’s
Chip Seal
70 – 100 mm M4
150 mm design depth
AP40 + 4% cement, UCS
= 3 – 4 MPa
100 mm Sub-base
Subgrade CBR 2%
1983
Not pre-cracked but calculated strain in
cemented layer would mean fatigue cracking
would have occurred early in the life of the
CTB. Design assumed residual stiffness =
1500MPa. No reflective cracking or deformation
to date on the surface.
Bay View Rd,
Dunedin
Kirkcaldy to
King Edward
4,400 vpd
2% HCV’s
Prime and seal G4
70 – 100 mm M4
170 mm design depth AP
40 + 4% cement, UCS = 3
– 4 MPa
100 mm Sub-base
Subgrade CBR 2%
1984
Not pre-cracked and calculated strain in
cemented layer would mean fatigue cracking
would not occur early in life in the CTB.
Shrinkage cracking at 3 – 5 m centres very
likely. No reflective cracking or deformation to
date on the surface.
Bay View Rd
Forbury Rd to
Surrey St
ADT 4,400
2%HCV’s
Two coat emulsion first
coat
150 mm M4
230 mm design depth AP
40 + 4% cement, UCS = 3
– 4 MPa
100 mm Sub-base
Subgrade CBR 2%
1985
Not pre-cracked. Expect design life before
fatigue.
No sign of cracks
Examples of CTSB Pavements
Site
Loading
Pavement Profile
Date
Comments
Main South
Rd, Dunedin
City
First Section
8,000 vpd
5% HCV’s
40 mm dense graded AC
170 mm design depth
AP40 + 4% cement, UCS
= 3 – 4 MPa
100 mm Sub-base
Subgrade CBR 4%
1986
Not pre-cracked but calculated strain in
cemented layer would mean fatigue cracking
would have occurred early in the life of the
CTB. Design assumed residual stiffness =
1500MPa. Reflective cracking occurred after
several years on the surface but not wide
cracking. Resurfaced with OGPA (prep with
chip seal to waterproof). Some fine reflective
cracking again showing, no crack sealing
carried out. Shape is still good.
Main South
Rd, Dunedin
City
Second
Section
8,000 vpd
5% HCV’s
40 mm dense graded AC
220 mm design depth
AP40 + 4% cement, UCS
= 3 – 4 MPa
100 mm Sub-base
Subgrade CBR 4%
1987
Not pre-cracked and calculated strain in
cemented layer would mean fatigue would not
occur for 20 years in the CTB. No reflective
cracking to date. Shape good.
Fox St,
Dunedin City
600 vpd
6% HCV’s
Thin AC
Two coat emulsion first
coat
150mm Basecourse,
250 Cemented M/4,
150 insitu material,
2%CBR
1989
Not pre-cracked, no fatigue expected in design
period, no signs of cracking at surface to date.
This is a light industry area. Road recently
resurfaced with thin AC.
SH 16,
Waimauku
10,000 vpd
8% HCV’s
Chip Seal
220 mm design depth
AP40 + 7% cement
200 mm sub-base?
Subgrade CBR 2%
2002
Pavement constructed over a section of soft
subgrade, within a long length of AWPT where
basecourse was modified with 3% cement. No
reflective cracking or deformation evident yet.
13
SAC + CTB Pavement at Intersections
Traffic loading 3 x 107 ESA’s
35 – 40 mm of SMA
E= 1500 MPa
100 mm Superpave14
E = 2500 MPa
Polymer modified
(4% sbs) seal
200mm
Subgrade CBR = 7%
E = 70 MPa
cracked
CTSB (180 mm GAP
65 + 50 mm sand
subgrade)
E = 1000 MPa
14