Use of compartmented sodium- alginate fibres as a healing agent delivery system for asphalt pavements

Use of Compartmented

Sodium-Alginate Fibres as a Healing Agent

Delivery System for Asphalt

Pavements

Tabaković, A.*; Post, W.; Garcia, S.J. & Schlangen, E.

Delft University of Technology

*Contact: a.tabakovic@tudelft.nl

E – MRS 2015 Fall Meeting 14th_{– 18}th_{September 2015}

Motivation

•

Preservation of the EU road network

The European Commission: “Transport infrastructure influences both economic

growth and social cohesion. A region cannot be competitive without an efficient

transport network.” (Vita and Marolda, 2008)

•

Length of road network:

• Global 16.3 mil. km

• EU 5 mil. km

• USA 4,4mil. km,

• China 3,1 mil. km

•

Maintenance Expenditure (€)

1.

Increased Inspection and Maintenance – inspection and maintenance at

regular intervals.

2.

Design standards – enhance asphalt pavement performance, to increase its

durability and improve its load carrying capability.

Road Failure Prevention Methods

3

•

Nanoparticles:

• Nanoclay

• Nanorubber

•

Induction heating

Types of Self Healing Technology for

Asphalt Pavements

Binder Rejuvenation

• Nanoparticles:

• Nanoclay

• Nanorubber

• Induction heating

•

Rejuvenation

Types of Self Healing Technology for

Asphalt Pavements

• Rejuvenators types:

• Industrially produced rejuvenator, e.g. Latexfalt Modiseal R20,

• High pen value binder,

• Organic oils:

• Vegetable oils,

Binder Rejuvenation

•

Strength recovery – 3PB Test

0 0,02 0,04 0,06 0,08 0,1 0,12 0,14 0 0,2 0,4 0,6 0,8 1 1,2 L o ad ( kN ) Displacement (mm) 0 0,02 0,04 0,06 0,08 0,1 0,12 0,14 0 0,2 0,4 0,6 0,8 1 1,2 L o ad ( kN ) Displacement (mm) Healing @ 20o_{C for 3h} 7 0 10 20 30 40 50 60 70 80 90 100 1st healing H ea lin g E ff ic ie n cy ( % )

• Simply applying rejuvenator to the surface of the pavement means that rejuvenator penetrates only top few mm of the pavement.

• Solution – embed microcapsules/hollow fibres, containing the rejuvenator, throughout

the asphalt matrix.

• How does it work?

• Fibres vs Microcapsule as rejuvenator encapsulation method:

Rejuvenator Encapsulation

9

i. Efficient production method – Spinning/Weaving,

ii. Fibre increases material strength,

iii. Higher delivery of rejuvenator to the damaged site.

Microcapsule _Fibres 0,000 0,005 0,010 0,015 0,020 0,025 0 2 4 6 8 10 12 V o lu m e o f re ju ve n at o r re le as ed ( m m 3 )

Volume of Microcapsules/Fibres in the model (mm3₎ Hollow Fibre

• Compartmented fibres – contain healing agent/rejuvenator in pockets throughout the length of the fibre.

Compartmented Fibres

Existing Self Healing Concepts using Embedded Fibres, a) Hollow Fibres, b) Compartmented Fibres (Garcia, 2014, Smart Polymers, Ch. 9.)

a) b)

• Advantages – compartmented fibres allow multiple healing events.

0,000 0,005 0,010 0,015 0,020 0,025 0 2 4 6 8 10 12 V o lu m e o f re ju ve n at o r re le as ed ( m m 3 )

Volume of Microcapsules/Fibres in the model (mm3₎ Hollow Fibre

Compartmented Fibres Microcapsule

Sodium Alginate

• Sodium Alginate is a promising methodology currently being investigated and

developed for the production of:

• Microcapsules - bacteria encapsulation for self healing of concrete, (Palin, et al. 2015),

• Compartmented fibres - encapsulation of healing agents for polymer based composites,

(van der Zwaag, et al. 2014).

11

• Advantages of Sodium Alginate as Rejuvenator encapsulation material:

• Low cost,

• Organic – non toxic, low impact on the environment,

• Solution:

• 6,0 wt% sodium alginate solution in demineralized water,

• 2,3 wt% PEMA solution in water (ratio PEMA : Alginate = 1:100),

• Ratio rejuvenator : Alginate = 40:60 in weight%.

Solution is stirred manually for 20 seconds. The size of the rejuvenator compartments can be controlled by increasing or decreasing mixing speed. The higher the mixing speed the smaller the compartments.

Sodium Alginate Compartmented

Fibres – Production Process

Sodium Alginate Compartmented

Fibres Containing Rejuvenator

Thermal Properties of Sodium Alginate

Fibres Containing Rejuvenator

70 75 80 85 90 95 100 40 60 80 100 120 140 160 180 200 220 240 260 280 300 F ib re W ei g h t lo ss ( % ) Temperature (o_C) 92,5%

Tensile Strength of Sodium Alginate

Fibres Containing Rejuvenator

• Fibre average diameter = 170µm cross sectional area = 0,023mm2

• Ultimate Tensile Strength (UTS) = 60,4MPa

15 0 10 20 30 40 50 60 70 0 0,02 0,04 0,06 0,08 0,1 S tr es s (M P a) Strain

Asphalt Mortar Mix with Fibres

Mix Constituent

Percentage weight in

the mix (%)

Sand

49,4

Filler

24,7

Fibres

1,3

Healing Efficiency of Sodium Alginate

Fibres Containing Rejuvenator

• Three point bend test:

• Loading rate = 0,1mm/s

• Test temperature = 20o_C

• Healing @ 20 ±±±±3 oC

i. First healing stage 30 minutes after the initial test

ii. Second healing stage 1 hour after the second test

iii. Third healing stage 3 hours after the third test

0 0,01 0,02 0,03 0,04 0,05 0,06 0,07 0,08 0 1 2 3 4 5 6 7 L o ad ( kN ) Displacement (mm)

Specimen with fibres Specimen without fibres

0 1 2 3 4 5 6 7 Displacement (mm) 0 1 2 3 4 5 6 7 Displacement (mm) 0 1 2 3 4 5 6 7 Displacement (mm)

Initial test Second test – after 1st

healing

Third test – after 2nd

healing

Fourth test – after 3rd

healing

17

Healing Efficiency of Sodium Alginate

Fibres Containing Rejuvenator

• Three point bend test:

• Loading rate = 0,1mm/s

• Test temperature = -5 o_{C – test specimen conditioning time 3 hours prior to testing}

• Healing @ 20 ±±±±3 oC

i. First healing stage 3 hours after the initial test

ii. Second healing stage 12 hours after the second test

0,0 0,1 0,2 0,3 0,4 0,5 0,0 0,2 0,4 0,6 0,8 1,0 1,2 L o ad ( kN ) Displacement (mm)

Specimen with fibres Specimen without fibres

0 0,1 0,2 0,3 0,4 0,5 0,0 0,2 0,4 0,6 0,8 1,0 1,2 L o ad ( kN ) Displacement (mm)

Specimen with fibres Specimen without fibres

0 0,1 0,2 0,3 0,4 0,5 0,0 0,2 0,4 0,6 0,8 1,0 1,2 L o ad ( kN ) Displacement (mm)

Specimen with fibres Specimen without fibres

Initial test Second test – after 1st _{Third test – after 2}nd

Healing Efficiency of Sodium Alginate

Fibres Containing Rejuvenator

• Test temperature 20o_C 0 20 40 60 80 100

1st Healing 2nd Healing 3rd Healing

H ea lin g R at e (% )

Specimen with fibres Specimen without fibres

• Test temperature -5o_C 0 20 40 60 80 100 1st Healing 2nd Healing H ea lin g R at e (% )

Specimen with fibres Specimen without fibres

Conclusions

•

Results demonstrate that rejuvenators can heal bitumen damage.

•

Sodium Alginate Compartmented Fibres effectively encapsulate bitumen

rejuvenator.

•

Sodium Alginate Compartmented Fibres demonstrated good thermal and

mechanical strength.

•

Fibres increase asphalt mortar strength by up to 36%.

•

Sodium Alginate Compartmented Fibres encapsulated Rejuvenator

(healing system) showed limited healing capacity.

•

Bitumen rejuvenator encapsulated in Sodium Alginate fibres shows

Acknowledgements

21

•

This research has been conducted as part of the Self-Healing Asphalt for

Road Pavements (SHARP) research project, under the FP7 Marie Curie

IEF research funding scheme.

•

Contact:

Dr. Amir Tabakovi

ć

Research Fellow – SHARP research project,

Materials & Environment, Faculty CiTG,

Delft University of Technology,

The Netherlands.

Phone: +31 (0)15 27 81985

Email: a.tabakovic@tudelft.nl