Rubberasfalt in de wegenbouw

Fedde Tolman

Hollandsche Beton Groep - Civiel

Netherlands Pavement Consultants bv

contents

pavements asphalt bitumen modified bitumen rubber modified binder

pavements

primary function: transfer forces from vehicle to earth

loads on pavements traffic

- mechanical

- noise

weather- moisture induced softening of grain material

- high temperature softening

- cracking due to restrained shrinkage

pavement performance- crack control- evenness- fixation of particles- skid resistance- visibility noise

applications- roads- industrial areas- airports- bridge decks- steel: structural- concrete: environmental protection- floors

Pavement structurename material thickness

(cm)criteria

toplayer- wearing course- friction course- sealing course

asphalt, concrete,epoxy, (elements)

2 – 5 user oriented performance

structural layers asphalt, concrete,elements

8 – 25 bearing capacitysheltering lower layers fromwater ingress

foundation- bound layers- unbound layers

sand, gravel, stone,cementitious materials,slag

10 – 40 bearing capacity

improved soil removing organicmaterialmixing additions

10 - 50 bearing capacityeven settlement(frost heave)

soil even settlement

composition asphalt mineral (type and gradation) bitumen (pen) additives pores

type size in mm(The Netherlands) function in asphaltstone (gravel) > 2 stability asphaltsand 0.063 – 2 stability asphalt, contact surfacefiller < 0.063 stability and consistency binderfibres diameter 0.01

length 1 mmconsistency binder

Most important Dutch asphalt types

class name characteristicdense asphalt concreteopen asphalt concrete

concrete

stone (gravel, sand)asphalt concrete

most dense granular structurebitumen glue and fillingpores (2 – 4 %) to avoid excess of bitumenmoderate in cost, production and operation

porous asphalt most open structure (20 – 30 % pores)water disposal and noise reductionrisk of abrasion and clogging

stone types

stone mastic asphalt granular skeleton filled with binderstrong, abrasion resistant and durablerisk of overfilling and instability

gussasphalthot rolled asphaltinterlayersealings and coatings

mastic

joints

bituminous continuumstabilised by mineralsabrasion resistant, crack bridging, durable

bitumen Samenstelling

– asfaltenen– maltenen– alifaten– aromaten

karakterisering– rheologisch (modulus en fasehoek)– empirisch (penetratie en verwekingspunt)– functioneel empirisch (breekpunt,

verwekingspunt, mengviscositeit)

Polymer modifications

class type % in bitumengummi latex 3

tires 10elastomer SB, SBR, SBS 6

EPDM 4plastomer PE, PP 5

EVA 4EMA, EBA 4PVC

Inert and chemical modifications

class type % in bitumenfibres rockwool 6

cellulose 3 ?polyester, polypropylene 6

fillers stone 40chalk 30carbon 15

natural C-H types natural asphalt 40 - 50‘gilsonite’ 5 - 10

oxidants Mn 2S 2multiphalt process -

Consistency - temperature

-250

-200

-150

-100

-50

0

-50 0 50 100 150 200T [C]

consis

tency

bitumen

plastomeer

elastomeer

mixing

compaction

use high T

use low T

T

Force - ductility

0

1

0 50deformation

forc

ebitumen

plastomeer

elastomeer

SBS

Molecular distribution

0

2,5

5

7,5

10

1,5 2,5 3,5 4,5 5,5log(mol weight)

con

cen

tra

tion

aliphaten

aromaten

polaren

asphaltenes

polymer

Risks in modifications

- compatibility bitumen and polymer problematic (mixing of bindertypes)

- asphalt mixing and compaction higher risk of being problematic

- mechanical improvement unclear

- hot reuse in principle no problem

- registration of application regarding demolition

- quality control of procedure; tedious product control

Rubber in asphalt

1898 bitumen + dissolved rubber C. de Caudemberge (testsections in France,Spain, Brazil, Argentinie)

1930 – 1940 rubber powder procede to Stam andStork, pulvatex, mealorub, latex) <10% and ground tire (< 25 - 50%)

research and several testsections in TheNetherlands and Netherlands Indie

1948 rubber powder 5 – 7% extension of use to wearing and structuralcourses; USA

synthetic elastomers1985 porous asphalt with rubberbitumen

rubber in pavements: panacea?

– rubber modified binder in asphalt- stiffness, fatigue, stability (permanent deformation) - impact absorption and strength- damping of vibration- abrasion- noise- friction - reduced temperature sensitivity- durability (ageing, adhesion, friction)

Types of rubber applications

in asphalt- rubber granulate and filler in asphalt- blocks, tiles and slabs- joints

in binder- dissolved- emulsification- powder (5 – 7%)- tyre scrap (4 – 8 %)

motives:- improvement of pavement- recycling / waste reduction (esp. of wasted tyres)

sustainability- emission- exposure- toxicity environment

Effect rubber addition

0

25

50

75

100

0 2,5 5 7,5 10

% rubber

Trb

pen

flow (mm)

imact (g)

Proefvakken A10 1990 Rijksweg Vak

nr Mengseltype gewenst

bit. perc. meng-temp.

oor-deel

RW 10(HRR) dag 1

0 1 2 3 4 5

Standaard ZOAB 0/16 Rubberbitumen Rubberbitumen Bitumen 80/100 + 0,3 % organische vezels Rubberbitumen Rubberbitumen

4,5 4,5 5,5 5,5 4,5 5,5

150 170 170 150 170 170

+ = + +

RW 10(HRR) dag 2

6 7 8 9 10 11

Polybilt 103 Z (80/100 met 6 % EVA) Polybilt 103 Z (80/100 met 6 % EVA) Bitumen 80/100 + 0,6 % organische vezels Polybilt 103 Z (80/100 met 6 % EVA) Polybilt 103 Z (80/100 met 6 % EVA) Cariphalte DA (Pen 150 bitumen met 6 % SBS)

4,5 5,5 5,5 4,5 5,5 4,5

160 160 150 160 160 165

= = + = +

RW 10(HRR) dag 3

12 13 14 15 16 17 18 19

Cariphalte DA (Pen 150 bitumen met 6 % SBS) Bitumen 80/100 met aangepaste gradering Bitumen 160/210 Cariphalte DA (Pen 150 bitumen met 6 % SBS) Cariphalte DA (Pen 150 bitumen met 6 % SBS) Bitumen 80/100 met aangepaste gradering Bitumen 160/210 Bitumen 80/100 (Standaard ZOAB)

5,5 5,5 4,5 4,5 5,5 5,5 4,5 4,5

165 150 140 165 165 150 140 150

= + = =

Productie 18 juni (vakken 0 t/m 5)

aanleg ZOAB-proefvakken probleemloos vak 1 met 4,5% rubberbitumen stolling van

het bindmiddel: verpompbaarheid- bindmiddeltemperatuur verhoogd viscositeit - pomp roerketel en installatie in serie druk

vak 2 (5,5 %) geen problemen vak 4 (4,5%) zelfde problemen als vak 1 vak 5 (5,5%) geen problemen

conclusions Technical

– bitumen are the main binding part; polymers and rubbers are specific

– mechanical properties may be improved but also worsened by rubber addition

– quality control problematic– no final qualification

Environmental– reuse tires – reduction noise– higher production temperatures

Health and safety– exposition to tire components– higher temperatures --> more emissions

perspectives

Rubber remains of interest for modifying binders and may become so as granulates

noise and reuse most important motives vibration and impact may be of interest