EFFECTS OF HYDRATED LIME ON AGEING AND ......ResearchMethodology: Testing Programme Filler Tests and Characterisation 106 2. Particle shape and texture properties • Particle shape

EFFECTS OF HYDRATED LIME ON AGEING AND MOISTURE DAMAGE OF ASPHALT MASTICS AND MIXTURES

Prof. Gordon AireyDirector

Nottingham Transportation Engineering Centre (NTEC)University of Nottingham

credit to: Rami Alfaqawi, Bilal Zaidi and James Grenfell

Lord’s Cricket Ground, Thursday 16 November 2017

EFFECTS OF HYDRATED LIME ON AGEING AND MOISTURE DAMAGE OF ASPHALT MASTICS AND MIXTURES

Rami Alfaqawi, Bilal Zaidi, James Grenfell and Gordon AireyNottingham Transportation Engineering Centre (NTEC)

Lime in Road Solutions – Pushing the BoundaryA British Lime Association Conference

Presentation Content

95

EFFECTS OF HYDRATED LIME ON AGEING OF ASPHALT MASTICS AND MIXTURES

Introduction

• Age hardening of bitumen is one of the key factors determining the durability of an asphalt pavement.

• The process of ageing involves chemical and/or physical changes that usually make bituminous materials harder and more brittle, thus increasing risk of pavement failure.

• Hydrated lime is already recognised as an additive for asphalt mixtures with positive effects on both ageing and moisture damage.

• Unique properties of hydrated lime, including particle size, higher porosity, surface chemistry, etc, make it an additive with an unique impact on the rheology and damage mechanics of asphalt mastics/mixtures.

96

Aim and Objectives

Aim:

Investigate the effect of using hydrated lime on ageing ofasphalt mastics and mixtures.

Objectives:

• Evaluate the effect of using Hydrated Lime (HL) on the chemical and rheological properties of mastics.

• Investigate the effect of HL on ageing of asphalt mixtures.• Quantify the relative effect for different aggregate/filler

types.100

Research Methodology:Materials:

Three types of fillers (All fillers were substantially finer than 63μm)

• Granite filler (G)• Limestone filler (LS)• Hydrated Lime (HL)

Two types of Bitumen• (B1) 40/60 Pen bitumen with a penetration of 45dmm

and a softening point of 50˚C

• (B2) 100/150 penetration grade bitumen with penetration of 119dmm and softening point of 44.8˚C

101

Research Methodology:Testing Programme

ResultsAnalysis of result and conclusions

Mastics Ageing EvaluationRheological and chemical evaluation of aged mastics/mixtures

Mastics/mixture Preparation and Ageing Mixing and ageing procedures

Filler TestsFiller selection and characterisation

102

Research Methodology:Mastic Phase

Research Methodology:Mixture Phase

104


Filler Tests and Characterisation

105

1. Particle size distribution • A Beckman Particle Size Analyser (LS200) was used for measuring

the particle size distribution of Granite fillers• Hydrated lime Particle Size distribution was given by the supplier

and determined using a Malvern Mastersizer


Filler Tests and Characterisation

106

2. Particle shape and texture properties• Particle shape and texture assessed with Scanning Electron

Microscopy (SEM) imaging

3. Particle density• The particle density (SG) was measured by the pycnometer method

in accordance to BS EN 1097-7:2008

4. Specific surface area• The BET method was used for the calculation of SSA

5. Fractional voids• The voids in dry compacted filler or Rigden Voids (RV) were

calculated in accordance with BS EN 1097-4:2008

1. Short-term ageing• The Thin Film Oven Test (TFOT) according to BS-EN 12607-2:2000

2. Long-term ageing• The Pressure Ageing Vessel (PAV) ageing procedure is used to

simulate long-term field oxidative ageing of asphalt binders inaccordance with BS-EN 14769:2012 (90̊C for 20 hours)

3. Ageing time study • The mastics aged in the TFOT oven for different ageing times up to

20 hours (0, 2, 5, 10 and 20 hours)


Mastics Ageing

107

1. Dynamic Shear Rheometer• The rheological properties of the mastics were characterised in this

study with a Bohlin Gemini model DSR• Frequency Sweep• 0.3% strain• 0.1 to 10Hz• 0 to 50˚C• G* and Phase angle (δ) Master curves @ 30°C reference

temperature

• Ageing index at 20°C and 0.4 Hz


Mastics Evaluation

108

masticagedun

masticaged

G

GIndexAging

2. Chemical analysis of bitumen and mastics• Fourier transform infrared (FTIR) test was performed on the

recovered bitumen from mastics before and after ageing

• Carbonyl C=O ageing index was used to evaluate the effect of ageing on different mastics

• Carbonyl index = A1700/ΣA


Mastics Ageing Evaluation

109

ΣA = A1700 + A1600 + A1460 + A1376 + A1030 + A864 + A814 + A743 + A724 + A(2953, 2923, 2862)

Filler Properties

SEM images

SEM imaging of Fillers a) Granite, b) Limestone, c) Hydrated lime

Results and Discussion

110

Filler Type SpecificGravity

RigdenVoids (%)

Surfacearea (m2/g)

GradingD10 D50 D90

Granite (G) 2.66 47.15 1.26 1.07 14.5 55.10

Limestone (LS) 2.65 39.82 1.58 1.35 8.67 30.05

Hydrated Lime (HL) 2.22 61.62 2.24 1.50 7.13 20.27a b c

Granite and Limestone mastics G*

Results and DiscussionG* Ageing Index

111

Granite and Limestone mastics (AI)


112

Granite mastics (Viscosity AI)


113

Granite mastics (Viscosity AI)


114

Recovered binder from Granite mastics

Results and DiscussionFTIR spectrum

115

Recovered binder from Granite mastics

Results and DiscussionFTIR- Carbonyl index

116Carbonyl index for recovered binder

Ageing Index - G* at 20˚C and 0.4Hz with ageing timeGranite mastics

Results and DiscussionAgeing Time Study

117

Ageing Index – ITSM Granite mixture

Results and DiscussionMixture ageing

118

Ageing Index – ITSM Limestone mixture

Results and DiscussionMixture ageing

119

Research MethodologyTesting Programme

120

Surface energy measurements

Bitumen: Low energy surface

(Bitumen-filler mastic)

Contact Angle Method

Aggregate: High energy surface

Vapour Adsorption Method

Dynamic Vapour Sorption

Saturation Ageing Tensile Stiffness(SATS) Procedure

66%

49%

26%

6%

80%

Final Saturation Level

SATS - Filler type

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 20 40 60 80 100 120 140

Retained Saturation (%)

Ret

aine

d St

iffne

ss 15B Acidic Standard

15B Acidic Limestone Filler #2

15B Acidic Hydrated Lime

15B Acidic Granite Filler

SATS - Aggregate type + HL

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 20 40 60 80 100

Retained Saturation (%)

Ret

aine

d St

iffne

ss

15B

15D

15E

50C

60%15B - Basic

15B - Acidic+HLF

15B - Acidic

Peel test

ha = 0.25 mm, h = 0.1 mm, R = 10 mm/min

Pneumatic Adhesion Tensile Testing Instrument (PATTI)test

Experimental studyMoisture damage adhesion testing

126

Surface energy adhesion and debonding parameters

Results and DiscussionMoisture damage

127

30% ML+20% HL

Work of AdhesionWork of De-bonding

Rolling bottle percentage coating


128

Granite

Limest

one

Basalt

Greywack

e

0

20

40

60

80Pe

rcen

tage

Coa

ting

40-60 Bitumen 50% MF 40%MF+10% HL 30%MF+20% HL

* MF represents the mineral filler from the respective aggregate type

SATS retained stiffness


129

Granite aggregate

Results and DiscussionMoisture damage parameters

130

Limestone aggregate

Intrusive igneous rock

Calcium carbonate sedimentary rock

Results and DiscussionMoisture damage parameters

1310.0

0.5

1.0

1.5

PATTI

50%GW

40%GW+10%HL

30%GW+20%HL

Basalt aggregate

Greywacke aggregate

Extrusive fine-grained igneous rock

Sandstone sedimentary rock

Hydrated lime addition clearly has the ability to reduce theageing susceptibility of bituminous materials (mastics andmixtures

In general, resistance to ageing increases with increasinglime content

General consensus of the beneficial influence of hydratedlime on moisture damage resistance

However, performance is aggregate specific and not alwaysoptimized at highest lime contents

Observations

132

Documents

EFFECTS OF HYDRATED LIME ON AGEING AND ......ResearchMethodology: Testing Programme Filler Tests and Characterisation 106 2. Particle shape and texture properties • Particle shape