The cost-effective upgrading, preservation and rehabilitation of roads – optimising the use of

available technologies

G J Jordaan

A Kilian

Roads/transportation

health educationSocial interaction

Empower communities

Economic growth

markets

access

Road design

Main components:- Geometry- Road structure

(pavement)

Geometric design

• Major cost implications• Applicable criteria !

• First upgrade follow existing tracks

• Improve as needs arise• Applicable standards !

Roads MUST be safe !• Road user• Affected communities

Geometric design

Road design

Main components:- Geometry- Road structure

(pavement)

Fill or In - situ soil(sand-clay-rock)

Durable surface Asphalt/seal

High quality material- granular- stabilised

Medium quality material- granular- stabilised

Pavement structure

Road pavement structure

Designed to carry load

LoadTyre pressure

Protect sub-grade

DurableWater-proof

Importation of high quality materials

Costs of road construction

Normal 2 lane road (2016) ~

R 5 – 6 million / km

13© WJvdMS

PAVEMENT CLASS AND DESIGN BEARING CAPACITY (80 kN AXLES/LANE)GRANULAR BASES DATE 1996

S denotes Double Surface Treatment (seal or combinations of seal and slurry)

S125 G4

150 G6

S

S125 G4

125 G6

S100 G5125 C4

125 G5

125 C4

S125 G4

125 C4

S125 G4

150 G5

40A125 G2

150 C3

40A150 G2

150 G5

S*/30A150 G3

150 C4

S*/30A150 G3

150 G5

40A150 G2

200 C4

30A150 G2

200 G5

50A150 G1

250 C3

50A150 G1

300 C3

Foundation

S1 denotes Single Surface Treatment* If seal is used, increase C4 and G5 subbase thickness to 200mm.

S150 G3

150 C4

150 G3

150 G5

S

S125 G4

150 C4

S150 G4

150 G5

40A150 G2

250 C3

Symbol A denotes AG, AC, OR AS.A0, AP may be recommended as a surfacing measure for improved skid resistance when wet or to reduce water spray

(DRY REGIONS)

S1100 G4125 G6

S1100 G5100 C4

S125 G4

125 G6

S100 G5125 C4

S125 G4

150 G6

S125 G5

150 C4

150 G9

G10

S1100 G4125 G7

S1100 G5125 G7

S1100 G5100 G7

150 G7

150 G9

G10

ES0,010,3-1,0x10 4

ES0,031,0-3,0x10 4

ES0,13,0-10x10 4

ES0,30,1-0,3x10 6

ES10,3-1,0x10 6

ES31,0-3,0x10 6

ES103,0-10x10 6

ES3010-30x106

ES10030-100x10 6

ES0,0030,1-0,3x10 4ROAD CATEGORY

Most likely combinations of roadcategory and design bearing capacity.

A: Major interurbanfreeways and roads.(95 % approximatedesign reliability)

B: Interurbancollectors and majorrural roads.(90 % approximatedesign reliability)

C: Lightly traffickedrural roads andstrategic roads.(80 % approximatedesign reliability)

D: Light pavementstructures, ruralaccess roads.(50 % approximatedesign reliability)

Design catalogue

Draft TRH4 (1996):

• Granular (G1 – G4) / + (Cemented sub-base)

• Bituminous treated Base (BTB)

• Cement-Treated base (CTB)

Road structure (pavement)

Crushed stone Popular – proven concept

Construction: experience crucial ! - densities (top 50 mm!) - surface texture (tile texture !)

- cemented sub-baseSurfacing: durability ! - water-proofing - maintenance capabilityMaterial Availability – costly Design Applicability – costly option

16© WJvdMS

Bituminous Treated Base (BTB) Effective - higher order roads

Construction: - residual bitumen high - high quality materials - time of construction (fast)

Behaviour: - durable - flexible - water resistant

Design Applicability – costly option

Cement stabilisation:Popular - Relatively low cost

Construction: - weather conditions - mixing (time limits) - curing ! (carbonation)

Behaviour: - Cracking ! – crushing Material compatibility !

- mineralogy – Mica- Smectite- others e.g. - Chamosite, Fe-ions…...)

(conceal problems ~ sub- base)

Typical Example:Pavement design Road D**

Recommended design:(design report – catalogue design)Design traffic lading: – 6% growth < 0.5 ME80sB – Category road (up to 12 MESA)

• 40 A • 150 G2 • 250 C4

• Available materials –sufficient G6

Stabilization

19© WJvdMS

Mechanical Stabilization:• Mixing of materials to achieve better grading

Chemical Stabilization:• Lime• Cement• Bitumen• Emulsions• Polymers• “new products”

+ Slag / Fly ash

PI10 14

Cement Either Lime

?

Test or Indicator Material1 Design Equivalent Material Class

BSM1 BSM2 BSM3Soaked CBR (%) CS (98%) > 80    

NG (95%)   > 25 10 to 25

PlasticityIndex (PI)

CS < 8    NG < 8 6 to 12 < 15GS   6 to 12 < 15SSSC     < 15

Grading modulus NG 2.0 to 3.0 1.2 to 2.7 0.45 to 1.2GS   1.2 to 2.5 0.75 to 2.7

ITS (dry) (kPa) 150mm Specimen > 125 80 to 125 50 to 80

ITS (wet) (kPa) 150mm Specimen > 100 60 to 100 50 to 75

UCS (wet) (kPa) All 1 500 to 3 000 700 to 1 500 450 to 700

Retained Cohesion ITS Wet/Dry (%) All > 70 > 65 > 60

Cement (%) Min. 0.0 0.0 Not requiredMax. 0.7 0.5 Not required

GE-20 NANO( %) Min. 0.5 0.3 0.3Max. 1.0 0.7 0.7

         1CS – crushed stone, NG – natural gravel, GS – gravel soil, SSSC – sand, silty sand, silt, clay

Basic facts:

Need to be more cost effective !

Maun SA Design (TRH4) uses dates to 1980s

Use of natural materials ? New technologies (nano) developed -

wide application throughout world

southern Africa ?

23© WJvdMS

Bitumen stabilised materials

• Bitumen stabilised materials – stabilised with addition of small quantity of

either bitumen emulsion or foamed bitumen– recent years - major developments

in this field has led to introduction of new design and analysis approach

– important to appreciate the expected behaviour of these materials

SA roads “practitioners”

- notoriously conservative

mind shift required !E.g. :

Proven modifications- seldom used

GPDRT recognised need to improve: Problem:

excessive costs of road infrastructure

Solution: improve use of natural materials identify available / applicable

technologies e.g. nano technologies!

Pavement design

Consider basic available natural materials

- Geology !

Back to basics !

27© WJvdMS

Weinert (1980):Southern Africa – “Unique”

Basic rock formationsSeasonal RainfallHigh Temperatures

~ Weathering !

28© WJvdMS

N < 5 – must assume Smectite presence

“until the contrary can be proven” !!!

29© WJvdMS

Weinert (1980):Southern Africa – “Unique”

Seasonal RainfallHigh Temperatures~ weathering characteristics

“Problem materials” e.g.Smectite……….Mica…………….

Cohesion-less sandsOrganic material

Crushed shell (West coast)Pulverised corral (East coast)

Consider available materials

basic Geology: (Weinert, 1980) southern Africa almost unique ! - Basic rock types

- crystalline rocks and - argillaceous rocks

- High temperatures- Seasonal rainfall

= “Problem materials”-

31© WJvdMS

• Developed > 50 years old• Empirically derived• No improvement in

technology ????

Testing:Material indicators

32© WJvdMS

• Developed > 50 years old• Empirically derived• OMC >8% ; Fraction 0.075 >10%• PI < 0.075 mm fraction

• Mineral contents ?

Testing:Material indicators

Draft TRH4:

• Granular (G1 – G4) / + (Cemented sub-base)

• Bituminous treated Base (BTB)

• Cement-Treated base (CTB)

Cement stabilisation – Normal prediction of UCS strength

0 7 14 21 28 350

1

2

3

4

5

6

5.395.425.34

3.82

2.44

5.485.27

4.99

2.81

1.76

5.385.24

5.64

3.21

1.82

5.25.18

4.19

2.39

1.5

5.475.3

3.43

2.15

1.6

5.19

4.74

4.06

1.7

1.25

4.39

3.69

2.73

1.98

1.21

3.15

3.77

2.06

1.11

0.71

Days

UCS

(MPA

)G5 – 6% Cement ; 2 – 10% Mica – M Mshali M thesis

Road age – 8 years

Disintegration of cemented layer

Carbonation – negative!

Smectite? / Mica?

2015 - SA

J Available testing technology:X-Ray Diffraction Testing (XRD Scans)

Available materials;nano-technologies already tested with natural materials:

- organo-silanes (5 nm)- Polymers (various) (60 – 80 nm)

Small particles – improved mixing properties ! unique properties !proven material stabilising enhancements(with / without traditional stabilising agents)

Nano –technology =

Bitumen molecule ~ 5 000 nmNano-bond Polymer ~ 60 – 80 nmNano-silane (waterproof) ~ 5 – 6 nm

Coverage:1 litre = 99 litres

MARSHALL WET COMPRESSIVE STRENGTH AASHTO T165 / ASTM D1075

Binder AC-10 Binder AC-20 CRMB-1 PMB-400

500

1000

1500

2000

2500

3000

Control 2% Hydrated Lime 0.1% Zycosoil

M

arsh

all S

tabi

lity

(Kg)

Flow Values (mm)

Basalt Aggregate (DBM) : 45% 20 mm, 10% 10 mm, 45% less than 6 mm with stone dust Asphalt Grade: AC-20 (VG-30, 60-70 pen. Grade)

2% Hydrated Lime 0.1% Nano - silaneControl

NCAT

THE CHEMICAL ACTION

Aggregate / Soil / Clay / Sand surface silicate structure after nano-silane reaction

OSi

OSi

OSi

OSi

OSi

OSi

OSi

OO

Si

O

OO

O

Si

O

O

O

Si

O

O

O

Si

O

O OO O

O

O

Si

O

O

O

Si

O

O

O

Si

O

O

Si Si Si Si Si SiSiO

OO

OO O O OO

O OO O

OSi

OSi

OSi

OSi

OSi

OSi

OSi

OO

Si

O

O HO H

O

Si

O

O

Si

O

O H

O

Si

O

O OO O

O

O

Si

O

OH

O

Si

O

O H

O

Si

O

O HO H

Particle surface

-OH groups make surface very hydrophilic (water loving)

Particle surface

InternalSiloxane bonds

Aggregate / Soil / Clay / Sand surface silicate structure

Silanol Groups

Nano -silane creates molecular level hydrophobic zone (water repellent)

4 - 6 nm Alkyl Siloxane surface

BOIL TEST ASTM D3625 : EXTEND TO 6 HOURS

Basalt Aggregate (DBM) : 45% 20 mm, 10% 10 mm, 45% less than 6 mm with stone dust Asphalt Grade: AC-20 (VG-30, 60-70 penetration grade)

0102030405060708090

100

Control 2%Hydrated

Lime

0.5% Amine 0.1%ZycoTherm

10 min

30 min

1 hr

6 hrs% C

oate

d Ag

greg

ates

Alkyl siloxane (Nano-silane)

Bitumen adherence to aggregate

NCAT

Boil Test

(ASTM D 3625)

Percentage of retained Coating

After 10 min After 1 hr After 3 hr

Neat mix 50% 30% < 10%

Modified mix 100% 95% > 95%

BOIL TEST – 4.5% bitumen content (mod – 0.1% Alkyl siloxane) - neat and modified bitumen of 50/70 for 3 hrs of boiling. - 200 gm of mix is scooped from the laboratory prepared design - Conditioning = keeping it in an oven at 135°C for 2hrs. - After oven curing - 24 hrs air cooling. - Testing is done in a hot plate and the mix at room temperature is

transferred to the boiling water at 100°c. The boil test is extended for 3 hrs. Samples are collected at intervals.

(Tested – Cape Town 2015 - 50/70 pen bit)

Boil Test

(ASTM D 3625)

Percentage of retained Coating

After 10 min

After 1 hr

After 3 hr

Neat mix 50% 30% 10%

Modified mix 100% 95% 95%

Advantages : Polymer / organo-silane

modification of emulsions

Risk of cracking Flexibility Low application rates Water resistant Ease of construction Cost-effective use of natural

materials

Advantages over the traditional emulsions:

Improved distributionAssist “breaking” – no cementEase of constructionReduced risk – clogged nozzles Improved cost-effectiveness

GPDRT Experimental section - D1884

G7 material

Design traffic loading: 5 – 7 M E80s

General approach: – in-situ stabilisation + G1/G2 base

Required: Improve 150 mm base quality In-situ recycling

Tested:0.3% – 0.7% SS60 + 20% nano-polymers

Test Report :

HEIDELBERG WEST - MATERIAL TEST RESULTS

SAMPLE INFORMATION & PROPERTIESCONTAINER USED FOR SAMPLING Black Sampling Bags

MOISTURE CONDITION OFSAMPLE ON ARRIVAL

Slightly Moist

HOLE No. / Km. / CHAINAGE CH 4-950 LHSROAD No. OR NAME D1884

LAYER TESTED / SAMPLED FROM TP4-50+170(1st layer)GRADING ANALYSES - % PASSING SIEVES (TMH1 1986 : METHOD A1 (a)    75.0   100SIEVE 63.0   100  AN

ALYSES

53.0   100

  (mm)

37.5   87

  26.5   78    19.0   74    13.2   68

  4.75   59  2.00   54

(TMH A1a) 0.425   32    0.075   17

ATTERBERG LIMITS ANALYSIS (TMH1 1986 : METHOD A2 & A3 ; TMH1 1986;TMHA4 1974)

ATTERBERG LL% 24.1

LIMITS P.I. 2.5(TMH

A2&A3)LS% 1.2

GM 2.00 CLASSIFI -

CATIONH.R.B.* A-1-b(0)

    COLTO* G7    T.R.H. 14* G7

UNCONFINED COMPRESSIVE STRENGTH (TMH1 1986 : METHOD A7, A14 & A16T)

MOD AASHTO

OMC% 8.8

(TMH A7) MDD(KG/M3) 2126    COMP MC % 8.0

C.B.R. % SWELL 0.36KPA 100%   33

U.C.S. 98%   29(TMH A13T) 97%   27

  95%

  23

93%

  17

90%

  8

GRADING ANALYSES - % PASSING SIEVES (TMH1 1986 : METHOD A1 (a)SIEVE 63.0   100

  ANALYSES 53.0   100

  (mm) 37.5   87

  26.5   78    19.0   74    13.2   68

  4.75   59  2.00   54

(TMH A1a) 0.425   32    0.075   17

ATTERBERG LIMITS ANALYSIS (TMH1 1986 : METHOD A2 & A3 ; TMH1 1986;TMHA4 1974)

ATTERBERG LL% 24.1

LIMITS P.I. 2.5(TMH A2&A3) LS% 1.2

GM 2.00 CLASSIFI -

CATIONH.R.B.* A-1-b(0)

    COLTO* G7    T.R.H. 14* G7

UNCONFINED COMPRESSIVE STRENGTH (TMH1 1986 : METHOD A7, A14 & A16T)

MOD AASHTO OMC% 8.8(TMH A7) MDD(KG/M3) 2126

    COMP MC % 8.0C.B.R. % SWELL 0.36KPA 100%   33

U.C.S. 98%   29(TMH A13T) 97%   27

  95%   23

93%   17

90%   8

UCS /ITS TG2 L1 - TMH 1 Method A14/ A16T SECTION 1 - IN LABORATORY DESIGN

ROAD NAME D1884 (4+950 LHS) D1884 (4+950 RHS) LAYER   1st layer 1st layer DATE RECEIVED 24/03/2015 24/03/2015 CLIENT MARKINGS N/A N/A Maximum dry density (MDD) 2126 2084 Optimum moisture content (OMC) 8.8 8.6 Date tested 02/04/2015 02/04/2015

ITS - STRENGTH OF BRIQUETTES (DRY) Binding Agent Content 0.7% GE-20 0.7% GE-20 Cement Content     Compaction effort (%) 100% 100% Dry Density (kg/m³) 2135 2101 Maximum load applied (kN) 4.32 3.78 Indirect Tensile Strength (ITS) (kPa) 383 391

UCS - STRENGTH OF BRIQUETTES (DRY) Binding Agent Content 0.7% GE-20 0.7% GE-20 Cement Content     Compaction effort (%) 100% 100% Dry Density (kg/m³) 2126 2092 Maximum load applied (kN) 41.38 39.64 UCS TMH1 A14 (kPa) 2269 2173

ITS-STRENGTH OF BRIQUETTES (SOAKED) Binding Agent Content 0.7% GE-20 0.7% GE-20 Cement Content     Compaction effort (%) 100% 100% Dry Density (kg/m³) 2139 2094 Maximum load applied (kN) - - Indirect Tensile Strength (ITS) (kPa) 142 124

UCS-STRENGTH OF BRIQUETTES (SOAKED) Binding Agent Content 0.7% GE-20 0.7% GE-20 Cement Content     Compaction effort (%) 100% 100% Dry Density (kg/m³) 2115 2080 Maximum load applied (kN) 6.98 7.14 UCS TMH1 A14 (kPa) 2139 2094 BSM Classification BSM3 BSM3 Test Type 48 hour curing 48 hour curing  

ITS - STRENGTH OF BRIQUETTES (DRY)  

Binding Agent Content 0.7% GE-20 0.7% GE-20  

Cement Content      

Compaction effort (%) 100% 100%  

ITS (kPa) 383 391  

UCS - STRENGTH OF BRIQUETTES (DRY)  

Binding Agent Content 0.7% GE-20 0.7% GE-20  

Cement Content      

Compaction effort (%) 100% 100%  

UCS TMH1 A14 (kPa) 2269 2173  

ITS-STRENGTH OF BRIQUETTES (SOAKED)  

Binding Agent Content 0.7% GE-20 0.7% GE-20  

Cement Content      

Compaction effort (%) 100% 100%  

ITS (kPa) 142 124  

UCS-STRENGTH OF BRIQUETTES (SOAKED)  

Binding Agent Content 0.7% GE-20 0.7% GE-20  

Cement Content      

Compaction effort (%) 100% 100%  

UCS TMH1 A14 (kPa) 2139 2094  

BSM Classification BSM3 BSM3  

Test Type 48 hour curing 48 hour curing  

Test or Indicator Material1 Design Equivalent Material Class

BSM1 BSM2 BSM3Soaked CBR (%) CS (98%) > 80    

NG (95%)   > 25 10 to 25

PlasticityIndex (PI)

CS < 8    NG < 8 6 to 12 < 15GS   6 to 12 < 15SSSC     < 15

Grading modulus NG 2.0 to 3.0 1.2 to 2.7 0.45 to 1.2GS   1.2 to 2.5 0.75 to 2.7

ITS (dry) (kPa) 150mm Specimen > 125 80 to 125 50 to 80

ITS (wet) (kPa) 150mm Specimen > 100 60 to 100 50 to 75

UCS (wet) (kPa) All 1 500 to 3 000 700 to 1 500 450 to 700

Retained Cohesion ITS Wet/Dry (%) All > 70 > 65 > 60

Cement (%) Min. 0.0 0.0 Not requiredMax. 0.7 0.5 Not required

GE-20 NANO( %) Min. 0.5 0.3 0.3Max. 1.0 0.7 0.7

         1CS – crushed stone, NG – natural gravel, GS – gravel soil, SSSC – sand, silty sand, silt, clay

GPDRT Experimental section - D1884

CSIR – HVS testing(construction:

specialised testing)

University of Pretoria -Post graduate students

Research : University of Pretoria

Materials/minerologyA B C D E

Stabilisingagents

1

2

3

Objectives: - improved guidelinesmineralogy / applicable stabilising agent

~ affordable road infrastructure

Mica / cement study – bench mark

Thohoyandou - 5 December 2015

25 January 2016

ThohoyandouNano-prime• prime Saturday 30/01/2016• Rain Sunday 31/01/2016• Picture: Monday 01/02/2016

USA experience

FINER DROPLET SIZE & QUICKER ABSORPTION

BITUMEN DROPLETS

Aim: Cost-effective design

Engineering = risk management All plain sailing?