evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. ·...
TRANSCRIPT
![Page 1: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/1.jpg)
Evaluation of a nano-silane-modified emulsion stabilised base and subbase under HVS traffic
FC Rust, I Akhalwaya*, GJ Jordaan, L du Plessis
*CSIR Smart Mobility
![Page 2: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/2.jpg)
INTRODUCTION AND PURPOSE OF THE PAPER
Nano-silane-modified emulsions provide an opportunity for the cost-effective upgrading of roads using marginal materials
Demonstration Sections in Gauteng• D1884 (Meyerton) – ES3 and ES1 designs• K46 (Diepsloot – William Nicol) – ES10 design
CSIR Research Programme• Desktop studies, laboratory testing• Accelerated Pavement Testing (APT)
Purpose of Paper• First set of HVS results
CSIR Heavy Vehicle Simulator (HVS)
![Page 3: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/3.jpg)
SITE LOCATION AND PAVEMENT STRUCTURE
Provincial Road D1884 in Meyerton• Rehabilitation design traffic of 3 Million Equivalent Standard 80 kN Axle
loads (ES3 DESIGN)
Insitu Materials• G7/G8 material used for base and subbase• High percentages of clay and mica (marginal)• Successfully stabilised using an anionic
nano-silane-modified emulsion (NME)
![Page 4: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/4.jpg)
METHODOLOGY AND TESTING REGIME
CSIR D1884 HVS project• 3 months of testing (October 2018 to January 2019)• 24/7 testing regime• Bi-directional and wandering traffic• Wet testing included (significant rainfall also recorded)
Main objectives of the HVS project• Performance evaluation of NME base and subbase materials • Further proof testing of nanotechnology in South Africa• Generate data to optimise preliminary design catalogues
![Page 5: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/5.jpg)
LOAD APPLICATIONS TO HVS SECTION
D1884 HVS Test Plan:
• 321,350 repetitions of a 40 kN dual wheel load (80 kN axle load) in the dry state
• 372,600 repetitions of a 60 kN dual wheel load (120 kN axle load) in the dry state
• 96,882 repetitions of an 80 kN dual wheel load (160 kN axle load) in the dry state
• 155,649 repetitions of an 80 kN dual wheel load (160 kN axle load) in the wet state.
• Tyre pressure = 800 kPa
![Page 6: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/6.jpg)
HVS RESULTS – RUT MEASUREMENTS
Measured with the CSIR’s laser profilometer
Final average rut depth of total HVS section = 8 mm • 7 million E80s (d = 4.2) • 3.5 million E80s (d = measured with HVS)
0 300 000 600 000 900 000Repetitions
Perm
anen
t Def
orm
atio
n (m
m)
2
4
6
8
0
![Page 7: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/7.jpg)
HVS RESULTS – ROAD SURFACE DEFLECTIONS
Measured with the CSIR’s Road Surface Deflectometer (RSD)
• Initial value of 0.36 mm• Increased to 0.71 mm with a max of 0.89 mm (at 40 kN measuring load)
0
0,2
0,4
0,6
0,8
1
1,2
1,4
Trafficking wheel load 40 kN Trafficking wheel load 60 kN Traffickingwheelload 80 kN
Trafficking wheel load 80 kN with water
Rebound after stoppage
Rebound after stoppage
0
0.8
1.2
0.4RSD
Def
lect
ions
(mm
)
![Page 8: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/8.jpg)
HVS RESULTS – PAVEMENT LAYER DEFLECTIONS
Measured with two CSIR Multi-Depth Deflectometers (MDD’s)LAYOUT OF SECTION 470A4
East (Traffic) Side
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Mdd Depths West (Caravan) SideLevel 1 0 mm deepLevel 2 200 mm deep NorthLevel 3 350 mm deepLevel 4 500 mm deepLevel 5 650 mm deep
MDD 4 MDD 12
Thermocoulpes (0 & 100 mm)
* * * * * * * * * * ** * *
* * *
* RSD Measuring positions
![Page 9: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/9.jpg)
HVS RESULTS – MDD DEFLECTIONS
• Total deflection under the 40 kN wheel load = 0.59 mm
• At 490,000 repetitions, 0.11 mm came from the NME base and 0.18 mm came from the NME subbase
0
Def
lect
ions
(mm
)
Repetitions300 000 600 000 900 0000
0.1
0
0.5
0.6
0.7
![Page 10: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/10.jpg)
HVS RESULTS – MDD DEFLECTIONS
• Most of the permanent deformation from base layer
• Acceptable in terms of pavement design guidelines = 3.6 mm
Def
orm
atio
n (m
m)
1
0300 000
Repetitions600 000 900 0000
4
5
6
![Page 11: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/11.jpg)
COMPARISON TO D1884 LABORATORY RESULTS
• Very high ITS values in line with previous findings for South African materials
Material ITSdr
y(kPa)
ITSwet(kPa)
(ITSwet/ITSdry)
UCSdry(kPa)
UCSwet(kPa)
(UCSdry/UCSwet)
Base layer: 1.5% modified emulsion
(1,5* liter / m3)
232 184 79% 2620 1865 71%
Sub-base layer: 1.2% modified emulsion
(1,5* liter / m3)
268 206 77% 4947 1670 34%
Sub-base layer: 1.0% modified emulsion
(1,5* liter / m3* )
420 321 76% 4807 831 17%
![Page 12: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/12.jpg)
DAMAGE COEFFICIENTS AND EQUIVALENT TRAFFIC
• Difficult to conclude using only one HVS test• Standard method used - rut rate (mm) per repetitions• Low damage factors indicates NMEs may be relatively insensitive to
overloading
Wheel load(kN)
Total traffic
repetitions
Repetitions for the
slope calculation
Rut (mm) d E80s (HVS) E80s (d =
4.2)
40 321,350 229,800 0.63 1 321,350 321,350
60 372,600 169,350 0.9 1.63249 722,287 2,045,626
80 96,882 83,500 1.1 2.26461 465,542 1,780,611
80 (wet) 155,649 133,400 4.738 3.69547 2,016,485 2,860,700
TOT E80s 3,525,664 7,008,287
![Page 13: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/13.jpg)
PAVEMENT STRUCTURE MODULI
• Back-calculated using MDD data• DCP testing also done inside and outside HVS section
Moduli (Mpa)DEPTH DCP
outside section
DCP in section
MDD 4 Average
MDD4 range MDD 12 Average
MDD 12 Range
Base252 309 173 69 - 797 127 71 - 214
Subbase245 246 93 40 - 142 98 71 - 134
350 - 500 mm deep145 193 154 75 - 316 174 82 - 606
500 - 650 mm deep108 121 205 136 - 268 198 160 - 268
550 - 800 mm deep99 220
![Page 14: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/14.jpg)
INTERPRETATION OF MODULI CALCULATIONS
Base Layer Interpretation• Initial stiffening phase due to compaction under the HVS traffic• Middle stable phase• End phase in fatigue
Average Calculated ModuliLAYER MDD 4
Base layer
MDD 4 Subbase layer
MDD 12 Base layer
MDD 12 Subbase layer
Phase 1 up to 108,000 repetitions 91 112 125 109Phase 2 from 108,000 to 679,000 repetitions
258 81 139 97
Phase 3 from 679,000 to 903,000 repetitions
104 96 104 88
![Page 15: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/15.jpg)
CONSTRUCTION COST COMPARISONS
• 43% cheaper - R18 million saving on a 6.2 km road (D1884)• 50% construction time saving for the project• There is still a need for a life-cycle cost investigation
40 mm AC
150 mm G1/G2
150 mm C3/C4
150 mm selected
Bitumen-rubber double seal
150 mm silane-modifiedemulsion (1,5%)
Compacted subgrade
150 mm silane-modifiedemulsion (1,0%)
Conventional ES3 design Alternative design
![Page 16: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/16.jpg)
CONCLUDING REMARKS
• HVS testing at D1884 indicated exceptional performance of this section• Nano-silane modification of marginal materials proven to be successful
on this site• This approach additionally yielded a 43% construction cost saving and a
50% construction time saving• There is a need for more HVS testing – current test K46 funded by
GPDRT near William Nicol Drive in Johannesburg
![Page 17: Evaluation of a nano-silane-modified emulsion stabilised base and subbase … · 2019. 10. 31. · • G7/G8 material used for base and subbase • High percentages of clay and mica](https://reader035.vdocuments.net/reader035/viewer/2022071517/613a7c180051793c8c0111d1/html5/thumbnails/17.jpg)
THANK YOU!
Acknowledgements to the Gauteng Province Department of Roads and Transport (GPDRT), Tshepega Engineering (Pty) Ltd and Kwagga Holdings (Pty) Ltd for HVS
funding
Contact Information: [email protected] or [email protected]
SO YOU’RE SAYING ENEMIES ARE NOW OUR
FRIENDS?
NO I AM SAYING NMEs ARE NOW OUR
FRIENDS