Performance characteristics of hot mix asphalt with ...

This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg)Nanyang Technological University, Singapore.

Performance characteristics of hot mix asphaltwith recycled materials

Lee, Zhen Hao.

2009

http://hdl.handle.net/10356/16328

Nanyang Technological University

Downloaded on 05 Feb 2022 22:17:59 SGT

Performance Characteristics of Hot Mix Asphalt With

Recycled Materials

Lee Zhen Hao

School of Civil and Environmental Engineering

College of Engineering


2009

ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library

Performance Characteristics of Hot Mix Asphalt

With Recycled Materials

Submitted by

Lee Zhen Hao

School of Civil and Environmental Engineering

College of Engineering


A Final Year Project Report presented to the


in partial fulfilment of the requirements for the

Degree of Bachelor of Engineering

2009


Summary

In this study, Recycled Concrete Aggregate (RCA) was used as a partial replacement of

Indonesian granite aggregates in LTA’s W3B mix to evaluate it’s feasibility in hot mix asphalt

(HMA) application.

Nine Marshall specimens were fabricated with a binder range of 4.75% to 5.25%. The optimum

binder content of 5.3% was adopted from the results of the Marshall Test. An amount of 50% of

the top three sieve sizes (>6.3mm) was replaced by RCA in the research.

Large pavement slabs of the hybrid mix were fabricated to simulate field constructed conditions.

Specimens were cored from the slabs and tests were conducted to compare the performance

characteristics of the hybrid HMA mix with conventional W3B mix.

The results from the creep tests, on average, revealed higher creep stiffness but lower

accumulated strain than those obtained by past studies which involved the fabrication of

conventional W3B slab specimens. The findings suggest that the hybrid mix is stiffer and less

able to take as much strain as LTA’s W3B mix.

The rutting tests showed that the hybrid mix has lower track rate, exhibiting higher rutting

resistance than the conventional W3B. This can be due to the specimens being heavily

compacted during the fabrication, which keeps the aggregate highly interlocked and resistant to

rutting.

ii


Acknowledgements

The author would like to express his gratitude and appreciation to his project supervisor, Dr

Wong Yiik Diew, who has spent invaluable time suggesting ideas, guidance and insights

throughout this study.

The author would also like to thank Dr Lum Kit Meng for his assistance and allowing the author

and his partner to work in the Transport Lab after office hours.

Thanks are extended to the Transportation Lab technicians, Mr Choi Siew Pheng, Ms Ng-Ho

Choo Hiang and Mr Andrew Liew Kai Liang for providing technical assistance and supplying

equipment for the project throughout this study.

The author would like to thank Ph. D. candidate Ms Anggraini Zulkati in providing much help

and advice during the duration of the research.

Lastly, the author would also like to thank his project partner Mr Loy Pei Ping for providing the

valuable support, effort and time to work with the author throughout the year of work.

iii


TABLE OF CONTENTS

Page

Summary 2

Acknowledgements 3

Table of Contents 4

List of Tables 7

List of Figures 8

List of Standards ix

Chapter 1: Introduction

1.1 Background 1

1.2 Objectives 2

1.3 Scope of Work 2

1.4 Organisation of Report 3

Chapter 2: Literature Review

2.1 Recycled Concrete Aggregate (RCA)

2.1.1 Past and Present Developments of RCA 5

2.1.2 Physical Properties of RCA 5

2.1.3 Mechanical Properties of RCA 6

2.2 Creep and Rutting Characteristics of HMA Pavement

2.2.1 Creep performance 7

2.2.2 Rutting Performance 7

Chapter 3: Material Properties and Characteristics

3.1 Introduction 8

3.2 Bitumen 8

3.3 Indonesian Granite 8

3.3.1 Physical and Mechanical Properties 9

3.3.2 Specific Gravity and Water Absorption 10

3.4 Recycled Concrete Aggregates (RCA) 11

3.4.1 Selection of RCA Source 11

3.4.2 Physical and Mechanical Properties of RCA 11

3.4.3 Selection of Aggregate Sizes for Replacement with RCA 12

3.4.4 Specific Gravity and Water Absorption 12

Chapter 4: Marshall Mix Design

4.1 Introduction 13

4.1.1 Marshall Design Criteria and Important Design Parameters 13

4.1.2 Specifications 14

iv


4.1.3 Aggregate Gradation 16

4.2 Marshall Test Results 18

Chapter 5: Slab Fabrication

5.1 Introduction 21

5.2 Specimen Fabrication 21

5.3 Asphalt Content Tester 23

Chapter 6: Dynamic Creep Test

6.1 Test Objectives 25

6.2 Test Procedure 25

6.3 Test Results 26

Chapter 7: Rutting Test

7.1 Test Objectives 28

7.2 Track Rate and Relative Rut Depth 28

7.3 Test Procedure 29

7.4 Test Results 30

Chapter 8: Conclusion and Discussion

8.1 Review of Results 31

8.2 Recommendations 32

References 33

v


APPENDICES

Appendix A Results for Change in Gradation of Recovered W3B-RCA Specimens

Appendix B Marshall Specimen Mass-Volume Relationship Table

Appendix C Measurements of Cored Specimens

Appendix D Results from Asphalt Content Tester

Appendix E Data Output from Dynamic Creep Test

Appendix F Time Schedule for Rutting Test

Appendix G Data Output from Rutting Test

vi


LIST OF TABLES

Page

Table 2.1 Typical Physical Properties of Processed 6

Reclaimed Concrete Material

Table 2.2 Typical Mechanical Properties of RCA 7

Table 3.1 LTA Requirements for Bitumen of Penetration 60/70 8

Table 3.2 Mechanical Properties and Requirements for Indonesian Granite 10

Table 3.3 Bulk Specific Gravity (OD) and Water Absorption of Indonesian 10

Granite (Cheong, 2007)

Table 3.4 Bulk Specific Gravity (OD) and Water Absorption of Indonesian 10

Granite (Ang, 2008)

Table 3.5 Mechanical Properties of RCA (Ang, 2008) 12

Table 3.6 Specific Gravity and Water Absorption for RCA (Ang, 2008) 12

Table 4.1 Important Design Parameters for Marshall Design Criteria 13

Table 4.2 Specification for Marshall Specimen Preparation 14

(ASTM D1559-89, 1994)

Table 4.3 LTA W3B Gradation Specifications 16

Table 4.4 Gradation of Hybrid Mix W3B-RCA27 18

Table 4.5 Summary of Marshall Specimen Test Results 18

Table 5.1 Gradation of W3B-RCA27 Slab Mix 21

Table 6.1 Dynamic Creep Test Conditions 26

Table 6.2 Dynamic Creep Test Results from Lee (2009) and Ho (2003) 27

Table 7.1 Rutting Test Results 30

vii


LIST OF FIGURES

Figure 1.1 Projects Flowchart 4

Figure 4.1 Graph of LTA’s W3B Gradation 16

Figure 4.2 Density, Flow, Stability (%), VTM (%), VFB (%), 19

VMA (%) vs Binder (%)

Figure 5.1 Wheel Roller Compactor (left), Machine Cutter (middle) 21

and Coring Machine (right)

Figure 5.2 Layout of Slab 23

Figure 5.3 Asphalt Content Tester 23

Figure 6.1 Universal Testing Machine (UTM) fitted with 25

Dynamic Creep Test Equipment

Figure 7.1 Wheel Tracking Machine 28

Figure 7.2 Cored Specimens S1-1 and S2-2 after Rutting Test 30

viii


LIST OF STANDARDS

AS 2891.12.1 – 1995 Determination of the Permanent Compressive Strain Characteristics

of Asphalt – Dynamic Creep Test

ASTM C127 – 04 Standard Test Method for Density, Relative Density (Specific

Gravity), and Absorption of Coarse Aggregate

ASTM D1559-89 Test Method for Resistance of Plastic Flow of Bituminous Mixtures

Using Marshall Apparatus

ASTM D2041 – 03a Standard Test Method for Theoretical Maximum Specific Gravity

and Density of Bituminous Paving Mixtures

ASTM D3549-03 Standard Test Method for Thickness or Height of Compacted

Bituminous Paving Mixture Specimens

ASTM D6926 – 04 Standard Practice For Preparation Of Bituminous Specimens Using

Marshall Apparatus

ASTM D6927 – 06 Standard Test Method for Marshall Stability and Flow of

Bituminous Mixtures

BS 598: PART 110: 1996 Method of Test for the Determination of Wheel-Tracking Rate

BS 812: PART 2: 1995 Methods of Determination of Density

ix


Chapter 1

INTRODUCTION

1.1 Background

Waste minimisation projects and research started many years ago. With an increasing waste

stream and global warming situation of our environment worsening over the past ten years, the

emphasis on waste minimisation has become even more crucial. Having effective ways to

minimise the amount of waste produced can contribute greatly towards protecting the

environment.

Several strategies are adopted by Singapore’s government to promote awareness of waste

minimisation. The aims are to formulate holistic waste minimisation policies and approaches,

undertake research and feasibility studies, encourage all sectors of the community to practise

waste minimisation and set up recycling programmes. Lastly, public education is to be given on

waste minimisation and recycling (NEA, 2002).

From a field trip by the author to Tuas Marine Transfer Station (TMTS) in September 2008, it

was found that out of the 350 hectares of landfill area, around 80 hectares of land has been

reclaimed up to the sea level. The Semakau landfill will be expected to meet Singapore’s need

for landfill space until 2045 (NEA, 2006).

In the year 2007, 778,300 tonnes of construction debris was produced in Singapore (NEA,

2008) and 98% of construction debris has been recycled. The remaining 2% consist of non-

recyclable or hazardous by-products that have to be disposed properly.

In Singapore, out of the total of $1.3 billion projected in the creation of Semakau Landfill, $610

million has been spent to date. Semakau Landfill is currently Singapore’s only landfill for waste

disposal. Due to Singapore’s lack of physical land area, recycling should play a major role in

reducing the landfill requirement. Use of recycled concrete aggregate (RCA) will also reduce

1


our dependency on raw material.

1.2 Objectives

The main objective of this research was to assess the feasibility of substitution of coarse granite

aggregate (>3.35mm) with RCA, based on equivalent-volume replacement. To achieve this, the

author conducted experiments to measure the specific gravity of granite and RCA. Next, the

author decided on a replacement percentage of granite aggregate with RCA in terms of

equivalent volume.

After this, the author used the Marshall Mix Design method to determine the optimum binder

content of Pen 60/70 bitumen for design mix with RCA. Finally, the author and his partner

determine the creep characteristics and rutting performance of the design mix by fabricating

slabs and testing the cored samples.

1.3 Scope of Work

The research comprised of stages as illustrated in Figure 1.1.

The first stage of work was literature review of past research on hot mix asphalt with recycled

materials done in NTU, as well as from other sources. Time was also assigned to the

familiarisation of test equipment to be used throughout the experiment.

The second stage was the selection of the materials required for the research, as well as to

determine the replacement percentage by volume of granite aggregate with RCA. This was done

by obtaining the specific gravity of batches of granite aggregate and RCA through measurement

tests and doing a density conversion. Marshall specimens were fabricated and tested to

determine the optimum binder content of the hybrid mix.

In the third stage the author produced slab specimens according to the hybrid mix and cored

samples from the slabs. Tests were conducted on the cored samples to determine their resistance

to creep and rutting.

2


The last stage involved the assessment of the test results and conclusions were made. This will

in turn allow for recommendation on further analysis of the feasibility of RCA.

1.4 Organisation of Report

The report is organised into 8 chapters, with the first chapter as the introduction.

Chapter 2 provides a literature review on the past and present developments of Recycled

Concrete Aggregate and past uses in pavement mixes.

Chapter 3 provides information on the physical and mechanical properties of the materials used

in the study.

Chapter 4 gives an in-depth review of the Marshall Mix Design Method. Trial hybrid Hot Mix

Asphalt (HMA) specimens are fabricated and tested. Important test parameters are discussed.

From various tests, the optimum binder content is obtained.

Chapter 5 involves the procedure for the fabrication of large slabs and the coring of sample

specimens to be tested. Physical parameters of the samples are measured and recorded.

Chapter 6 describes the Dynamic Creep test to obtain Creep Stiffness and Accumulated Strain.

Results are compared with previous studies.

Chapter 7 deals with the Rutting test conducted on large slab test samples and comparing the

results with past studies.

Chapter 8 summarises the findings of the study, reviewing the values obtained and giving

recommendations to improve the HMA mix design.

3


Figure 1.1 Project Tasks Flowchart

4

Identification of Objectives

Literature Review

Familiarisation of Test Equipment

Selection of Test EquipmentAggregate Material SelectionGraniteRecycled Concrete AggregateBinder Type

Mix Design and Specimen Preparation

Marshall Test (Destructive)

Determination of Optimum Binder Content

Preparation of Slab Specimens atOptimum Binder Content

Rutting Test Creep Test

Results and Discussions

Conclusions and Recommendations

Task 1

Task 2

Task 3

Task 4


Chapter 2

LITERATURE REVIEW

2.1 Recycled Concrete Aggregate (RCA)

2.1.1 Past and Present Developments of RCA

Countries like America, United Kingdom, Japan and Germany have researched in construction

and demolition (C&D) waste aiming to find possible uses of recycled concrete aggregate (RCA)

as an alternative to natural granite aggregate for the construction sectors (Cheong, 2007).

In 2003, a Federal Highway Administration (FHWA) report has shown that recycled concrete

aggregate (RCA) used in the base and sub-base material has a beneficial performance (Focus,

April 2004). In the report, it is found that RCA application provides engineering, economic, and

environmental benefits. With regards to the environment, the need for construction debris to be

disposed of to landfills is also eliminated. The California Department of Transportation’s

(Caltrans) has also discovered that even though start up costs for collecting RCA is high,

hauling and overhead cost is reduced (FHWA 2003). This issue is of a lower importance in

Singapore due to its small land area. It can be seen that there can be further expansion in RCA

application in highway pavements.

In Singapore, RCA is obtained through the crushing of C&D waste into controlled sizes. To

obtain a clean batch of RCA, the sorting process is inclusive of the removal of steel and weaker

materials like wood.

2.1.2 Physical Properties of RCA

RCA is produced from construction debris and is angular in shape. RCA is coated with mortar,

which is due to hydrated cement that remains adhered to the aggregate after the batching

5


process. This mortar may also contain cement paste that has not hydrated during the prior

construction phase. RCA has a surface texture which is rougher in comparison to virgin

Indonesian granite. It is also more porous, and has a lower specific gravity than Indonesian

granite.

Smaller RCA has a lower specific gravity compared to larger ones. This is because smaller RCA

has a proportionately larger surface area as compared to larger RCA. Smaller RCA tend to have

higher water absorption as well. Physical properties of RCA are given in Table 2.1.

Table 2.1 Typical Physical Properties of Processed Reclaimed Concrete Material (FHWA, 2006)

Property ValueSpecific Gravity, %

2.2 to 2.5

2.0 to 2.3

Coarse aggregate

Fine aggregate

Absorption, %

2 to 6

4 to 8

Coarse aggregate

Fine aggregate

2.1.3 Mechanical Properties of RCA

RCA that is larger than 4.75mm in size has been reported to have favourable mechanical

properties for aggregate use. RCA greater than 4.75mm in size has good abrasion resistance,

good bearing strength and good soundness characteristic. Magnesium sulfate soundness and

California Bearing Ratio (CBR) values are comparable to conventional granite aggregate. The

mechanical properties of RCA are given in Table 2.2.

6


Table 2.2 Typical Mechanical Properties of RCA (FHWA, 2006)

Property ValueLos Angeles Abrasion Loss (ASTM C131), %

20 – 45Coarse Aggregate

Magnesium Sulfate Soundness Loss (ASTM C88), %

< 4

< 9

Coarse Aggregate

Fine Aggregate

California Bearing Ratio (CBR), % 94 to 148

2.2 Creep and Rutting Characteristics of HMA Pavement

2.2.1 Creep performance

Creep is defined as the permanent deformation tendency of a material under loading. The rate of

such a deformation is a function of its material properties, time of exposure to loading as well as

the amount of applied stress. In this case creep deformation is time-dependent and occurs upon

accumulation of strain over a certain period of loading time.

HMA pavements that are subjected to traffic loading over a long period of time will eventually

develop creep deformation. Subsequently, this will result in rutting failure of the pavement.

2.2.2 Rutting Performance

Rutting is defined as the accumulation of small amounts of unrecoverable strain as a result of

repeated loading applied to the HMA pavement. The author performed creep tests and rutting

performance tests, simulating in-situ conditions, to estimate creep and rutting potential of the

design mix.

7


Chapter 3

MATERIAL PROPERTIES AND CHARACTERISTICS

3.1 Introduction

The HMA of this research consists of aggregate types comprising Indonesian granite and RCA,

as well as the binder bitumen. The properties of these materials shall be elaborated in this

chapter.

3.2 Bitumen

Bitumen is a black material which is a by-product of petroleum refining processes. It is highly

viscous at temperatures above 100 degrees Celsius and is solid at room temperature. At room

temperature it has excellent weathering properties, water resistance, flexibility and ductility.

Bitumen is widely used as binder of aggregate in flexible pavement construction. No tests were

done on the bitumen as tests have been performed by NTU students regularly in every semester

and consistent results that meet LTA’s requirements have been obtained. The required properties

are shown in Table 3.1.

Table 3.1 LTA Requirements for Bitumen of Penetration 60/70 (LTA. 2009)

Property RequirementsPenetration at 25oC, 100g, 5s (0.1mm) 60 - 70Softening point, ring and ball (oC) 47 – 56Flash point, Cleveland open cup (oC)

Thin film oven test, 3.2mm at 163 oC, 5hrs

(i) Loss in heating (% by weight)

(ii) Penetration of residue at 25 oC (% of original penetration)

(ii) Ductility of residue at 25 oC at 5cm/min (cm)

Min. 230

Max. 0.8

Min. 52

Min. 55Solubility in trichloroethylene (% by weight) Min. 99.5Specific gravity at 25 oC 1.0 – 1.11

3.3 Indonesian Granite

8


This research uses granite aggregate originating from Indonesia. The batch of Indonesian

granite was the same as Ang’s (2008). Coarse aggregate (>3.35mm) offers the major support in

carrying load, whereas the fine aggregate (<3.35mm) provides filler accommodation for the

voids in the binder mix. Selection of aggregate is determined by the following characteristics:

• Toughness

• Porosity

• Surface Texture

• Soundness

• Polish Resistance

• Specific Gravity

• Absorption and Affinity for Binder

• Sensitivity to Chemical Additives

• Particle Size And Aggregate Gradation

• Cleanliness (Or Clay Content)

• Particle Shape

3.3.1 Physical and Mechanical Properties

Cheong (2007) and Phoon (1998) have performed Los Angeles abrasion test, aggregate crushing

value test and 10% fines test on the Indonesian granite according to ASTM and Singapore

Standards. It is found that the mechanical properties of the granite meet the minimum

specifications set out by LTA. The following are the requirements by LTA as well as the results

of Cheong (2007) and Phoon’s (1998) studies, as shown in Table 3.2.

9


Table 3.2 Mechanical Properties and Requirements for Indonesian Granite (LTA 2009)

Property Measured Value Allowable Value Test MethodLos Angeles Abrasion Test 30.44% < 40.00% ASTM C131 – 06Aggregate Crushing Value Test 21.55% < 35.00% SS 73:197410% Fines Test 204.6kN > 130.000kN (NZ) SS 73:1974

The author has verified through consistent results in past reports that Indonesian granite is able

to meet the requirements as set out by LTA. Thus our batch of Indonesian granite is suitable for

use as an aggregate in HMA pavement construction.

3.3.2 Specific Gravity and Water Absorption

Specific gravity is defined as the ratio of the density of a given solid or liquid to the density of water

at a specific temperature and pressure. Aggregate with high voids will have a higher water

absorption compared to aggregate with low voids. More binder will be absorbed into aggregate with

high absorption, and this will cause a drop in the compactability of the mix.

Cheong (2007) has conducted specific gravity and water absorption tests according to BS 812:

Part 2. The figures are reported as in Tables 3.3.

Table 3.3: Bulk Specific Gravity (OD) and

Water Absorption of Indonesian Granite (Cheong, 2007)

Sizes (mm) Bulk Specific Gravity

(Oven Dry)

Water Absorption (%)

19.0 – 3.35 2.572 0.8243.35 – 1.18 2.590 0.634

1.18 – 0.3 2.586 0.929

10


Tests conducted by Ang (2008) gave results similar to Cheong’s (2007) and are summarised in

Table 3.4.

Table 3.4: Bulk Specific Gravity (OD) and

Water Absorption of Indonesian Granite (Ang, 2008)

Sizes (mm) Bulk Specific Gravity

(Oven Dry)

Water Absorption (%)

19- 13.5 2.592 0.435

13.5- 6.30 2.596 0.4476.30- 3.35 2.599 0.6153.35- 1.18 2.601 0.3561.18- 0.30 2.594 0.4360.30- 0.075 2.525 1.4210.075- pan 2.560 1.035

3.4 Recycled Concrete Aggregates (RCA)

3.4.1 Selection of RCA Source

The RCA used in this research is taken from Samwoh Recycling Plant. The batch of RCA used

in this research was the same as Ang’s (2008). In the Construction Laboratory, the author

checked the composition of granite and RCA by quickly washing the aggregates under running

water. RCA is more powdery than granite. White patches can be visibly seen adhered to the

surface of RCA. The batch of RCA was then sieved to obtain aggregate sizes corresponding to

those of the first 3 sieve sizes of LTA’s W3B Gradation. Debris material like chips of brick and

broken metal wires were removed during the sieving of RCA.

3.4.2 Physical and Mechanical Properties of RCA

Ang (2008) has done LA abrasion test, aggregate crushing value test and 10% fines test on this

batch of RCA to ensure that the mechanical properties of the aggregate meet the specifications

set out by LTA. The results are shown in Table 3.5.

11


Table 3.5 Mechanical Properties of RCA (Ang, 2008)

Property Measured Value LTA’s Allowable

Value

Test Method

Los Angeles abrasion test 32.30% < 40.00% ASTM C131 – 06Aggregate crushing value test 21.55% < 35.00% SS 73:197410% fines test 146.0kN > 130.000kN (NZ) SS 73:1974

3.4.3 Selection of Aggregate Sizes for Replacement with RCA

Ang’s (2008) report has shown that there is comparable strength and rutting performance in the

use of coarse RCA (>6.3mm) in HMA pavement. The author has conducted some visual

inspection and noticed how aggregate 3.35mm down consisted of mostly mortar which was

easily broken up into even smaller pieces. This is consistent with Ang’s (2008) inspection.

It is also reported from FHWA that the specific density of RCA decreases while water

absorption increases as the size of aggregate decreases. This is due to the higher mortar

proportion adhering to finer RCA (FHWA. 2006).

The performance of the hybrid mix will decrease in terms of flexural strength and deformation with

higher mortar content. Hence we will use coarse RCA and avoid the use of fine RCA in our

experiment.

3.4.4 Specific Gravity and Water Absorption

Ang (2008) has conducted specific gravity and water absorption tests for coarse RCA and they

found values consistent with those reported in the literature. RCA generally has a lower specific

gravity and higher water absorption than Indonesian Granite, as shown in Table 3.6.

Table 3.6 Specific Gravity and Water Absorption for RCA (Ang, 2008)

Sieve Size (mm) Bulk specific gravity (Oven Dry) Water Absorption (%)19.0 – 13.5 2.323 4.83913.5 – 9.5 2.328 4.9299.5 – 6.3 2.331 5.009

12


Chapter 4

MARSHALL MIX DESIGN

4.1 Introduction

The specifications for Marshall Specimen preparation will be covered in this chapter, as well as

the Marshall Design Criteria. Specimens will be fabricated according to a speculated range of

binder contents and tests will be conducted to obtain important design parameters. The optimum

binder content will be found from the results that meet the Marshall Design Criteria and this

binder content will be used for fabrication of the slab.

4.1.1 Marshall Design Criteria and Important Design Parameters

The Marshall Design Criteria is based on three volumetric properties and two mechanical

properties (see Table 4.1). The volumetric properties are Voids in total mix (VTM), Voids in

Mineral Aggregate (VMA), and Voids filled with binder (VFB). The two mechanical properties

are stability and flow. Using the mass-volume relationship of a Marshall specimen, it was found

out that stability and flow values are not greatly affected by the type of aggregate and asphalt

used, while the volumetric properties (VTM, VMA and VFB) are dependent on the quality of

the aggregate used.

Table 4.1 Important Design Parameters for Marshall Design Criteria

Property Limits

Mechanical Stability >9.0kN

Flow 8 to 16 units OR 2 to 4mm

Volumetric Voids in Total Mix, VTM 3 to 5%

Voids Filled with binder, VFB 75% to 82%

Past studies have highlighted that it is difficult to reach the design criteria. Values are often

found at the opposite limits within the criteria. For example, a mix that meets the criteria for

VFB at the upper limit may have a flow that is too high. Nevertheless, a compromise can be

13


made to choose an optimum binder content that will produce the best performance for the

hybrid mix.

4.1.2 Specifications

Table 4.2 shows the specifications for the production of a Marshall specimen.

Table 4.2 Specification for Marshall Specimen Preparation (ASTM D1559-89, 1994)

Aggregate Heating Temperature (2 hours) 105 - 110°CBitumen Heating Temperature (2 hours) 150°C (for PEN 60/70)

Compaction Temperature 135 - 150°C (for PEN 60/70)Tamper Foot Flat and circular with a diameter of 98.4 mm

corresponding to an area of 76 cm²Trowelling 15 times round the perimeter and 10 times in the

centre leaving a slightly rounded surface

Compaction Pressure 457.2 mm free fall drop distance of a hammer

assembly with a 4536 g sliding weightNumber of Blows 75 on each side ( for heavy traffic loading)

Mould Size 101.6 mm DiameterSpecimen Height 65 - 75mm

In our experiments, other than following the specifications in ASTM D1559-89, some

alterations were made due to lab constraints and to improve the quality of the specimen:

The aggregates and bitumen were put in the oven to be preheated at 120°C for 4 hours

instead of 2 hours and compaction was done at 100°C;

Pieces of round paper were cut and placed at the bottom and the top of the Marshall

specimen during the compaction to prevent the mixture from sticking to the metal collar;

The compacting mould, collar and base were oiled after the production of each specimen to

prevent the mixture from sticking to them.

In our preliminary, specimens were fabricated and broken up before compaction to test for

breakages of RCA by machine mixing. Tests were done with a total replacement of RCA with

the top three coarse grain sizes of granite aggregate for , with 2 W3B specimens for comparison.

14


The results from the test are shown in Appendix A.

The graphs in Appendix A showed that the recovered gradations of all four specimens have

fallen out of LTA’s specifications in the fines area of 1mm down. W3B has suffered, on average,

10.4% breakages in its coarse aggregate while the hybrid specimen has suffered 15.9% in

breakages of its coarse aggregate. The author concluded that the increase in breakages is due to

the inclusion of RCA in the mix.

In terms of fines, W3B specimens have a loss of 11.4% while RCA hybrid specimen 1 has a loss

of 9.04%. This can be due to mortar in the RCA clumping up into larger particles during

recovery, and are not washed away. Granite fines are free of mortar and cleaner than RCA. Thus

granite fines do not clump up together as easily. To conclude, it is seen that the amount of

breakage from RCA during machine mixing is rather negligible and will produce specimens of

comparable strength in terms of rutting and creep resistance.

For preparation of the actual Marshall specimens, the following improvements were made to the

procedure:

For consistency, the duration for machine mixing of the aggregates and bitumen was

restricted to 4 minutes. If the aggregates are found not to be totally covered in bitumen, the

mixture is given another 30 seconds of machine mixing. In this way, we minimise the

possibility of variances in performance due to breakages from machine mixing.

A spatula was used to push the mixture carefully into the mould to prevent segregation of

the aggregates.

For additional steps in Marshall Specimen production, after taking the specimens out from

the extruder, the top filter paper is then removed and the specimen is labelled with a wax

pencil. Finally the specimen is left to cool to room temperature.

In Ang’s (2008) report, the hand-mixing method was used for Marshall specimen

production. To better simulate an in-situ condition, the author has used machine mixing and

15


machine compaction in production of the Marshall mix specimens. During the process, care

was taken to guard against segregation of the aggregates when pouring the hot mix from

the machine-mix heating bowl into the Marshall mould.

4.1.3 Aggregate Gradation

In this research the LTA W3B gradation with nominal sieve size 13.2mm is adopted. Aggregates

were sieved and blended satisfying upper and lower limit requirements as shown in Figure 4.1

and Table 4.3. Aggregates of size 3.35mm and above are considered to be coarse aggregates and

those below are considered fines.

Table 4.3 LTA W3B Gradation Specifications

Sieve Size (mm) W3B Gradation Envelope Mid Value

Lower Higher

19 100 100 100 13.2 85 95 90 6.3 58 68 63

3.35 40 50 45

1.18 21 31 25

0.3 11 17 14

0.075 4 8 6

16


Figure 4.1 Graph of LTA’s W3B Gradation

LTA W3B Gradation

0

10

20

30

40

50

60

70

80

90

100

0.01 0.1 1 10 100Aggregate Size

Vo

lum

e P

ass

ing

(%

)

Upper Limit

Lower Limit

W3B(cm^3)

It has been found that previous design mix samples that have partial replacement of RCA by

Ang (2008) and Cheong (2007) are of a greater thickness. In a previous study of substitution of

granite for glass (Thein Moe, 2005), glass hybrid Marshall specimens have been found to be

generally thicker than the standard W3B Marshall specimen. This increased thickness is due to

‘over’ replacement of the aggregate by equivalent mass. Hence we have adopted the

replacement of Indonesian granite for RCA by equivalent volume.

Table 4.4 shows the gradation of the finalised hybrid mix. As 27% of the aggregate has been

substituted with RCA, the hybrid specimen shall be named W3B-RCA27.

17


Table 4.4 Gradation of Hybrid Mix W3B-RCA27

Sieve Size (mm) Weight (g)

W3B mix W3B-RCA27 mix

Granite Granite RCA

19 - 13.2 120 60 58.84

13.2 - 6.3 324 162 160.75

6.3 - 3.35 216 108 99.66

3.35 - 1.18 228 228 0

1.18 - 0.3 144 144 0

0.3 - 0.075 96 96 0

Pan 72 72 0

Total (g) 1200 1189.25

Total (cm^3) 463.32 463.32

Percent Aggregate (%) 100 73 27

Due to RCA’s lower density, the mass of RCA to be used in each sieve size is recalculated by

the following formula. Values of 2.59 and 2.43 were adopted from Cheong’s (2007) past results

in determining bulk specific gravity of Indonesian Granite and RCA respectively.

Weight of RCA to substitute = Weight of Granite Aggregate / Granite S.G. * RCA S.G

Whereby,

Specific Gravity of Indonesian Granite = 2.59

Specific Gravity of RCA = 2.43

4.2 Marshall Test Results

All specimens met the requirements for stability. All except Specimen 7 met LTA’s requirements

for flow, but only specimens 7, 8 and 9 met the requirements for VTM. None of the specimens

had met the requirements for VFB. The Mass-Volume Relationship calculation results are

included in Appendix B. The numeric results are summarised in Table 4.5.

Table 4.5 Summary of Marshall Specimen Test Results

18


Specimen No.

% Binder Flow(mm)

Corrected Stability (kN)

Density (g/cm3)

VTM% VMA% VFB%

1 4.75 3.43 13.375 2.26 5.90 14.94 60.51

2 4.75 2.957 17.124 2.28 5.11 14.23 64.09

3 4.75 3.378 16.656 2.27 5.57 14.65 61.95

4 5.00 3.075 15.138 2.25 5.75 15.33 62.49

5 5.00 2.861 14.128 2.26 5.67 15.26 62.83

6 5.00 2.853 13.993 2.27 5.11 14.75 65.39

7 5.25 4.495 17.366 2.28 4.28 14.54 70.57

8 5.25 3.186 16.164 2.28 4.56 14.79 69.16

9 5.25 3.866 16.932 2.30 3.71 14.03 73.59

The following trends were seen within this range of binder content. As binder content increases

from 4.75%, Density, Flow, Stability and VFB decreases. The minimum value is reached at

4.9%. Towards the bitumen content of 5.25%, Density, Flow, Stability and VFB increase. VTM

peaks at 4.9% and decreases as bitumen content increases. VMA increases until it reaches a

peak at 5%, then decreases as bitumen content increases.

The author has decided to adopt the optimum binder content 5.3% for the slab mix. This was

chosen to have values which are closest to the range of values required of the Marshall Design

Criteria.

According to the graph of VFB (%) vs Binder (%) in Figure 4.2, it is predicted that the VFB of

the mix will increase to a value higher than 75%. The hybrid specimen will have increased

stability. Flow will have a small increment and VTM will have a small decrement but not go out

of the bands, and this will meet the Marshall Design Criteria. Plot of these values are shown in

Figure 4.2.

19


Figure 4.2 Density, Flow, Stability (%), VTM (%), VFB (%), VMA (%) vs Binder (%)

Area of values which satisfies Marshall Design Criteria

20

VTM (%) vs Binder Content (%)

3.0

3.5

4.0

4.5

5.0

5.5

6.0

4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40 5.50

Binder Content (%)

VT

M (

%)

VMA (%) vs Binder Content (%)

13.5

14.0

14.5

15.0

15.5

4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40 5.50

Binder Content (%)

VM

A (

%)

VFB (%) vs Binder Content (%)

55

60

65

70

75

80

85

4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40 5.50

Binder Content (%)

VF

B (

%)

Stabili ty vs Binder Content (%)

5

7

9

11

13

15

17

19

4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40 5.50

Binder Content (%)

Sta

bil

ity

(k

N)

Flow vs Binder Content (%)

2

3

4

5

6

4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40 5.50

Binder Content (%)

Flo

w (

mm

)

Density vs Binder Content (%)

2.25

2.26

2.27

2.28

2.29

2.30

4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40 5.50

Binder Content (%)

De

nsit

y (g

/cm

^3)


Chapter 5

SLAB FABRICATION

5.1 Introduction

This chapter covers the fabrication of two slabs with the hybrid mix followed by the coring of

specimens.

5.2 Specimen Fabrication

The author included the production of a first ‘dummy’ slab, with two objectives. This slab had

aggregate samples with roughly the same weight and gradation as the two test slabs. Firstly, the

mixture will coat the chamber with binder, effectively conditioning it for the next two slabs.

With this “buttering” process the chamber of the mixer will be fully coated with binder and

additional compensatory binder will not be required.

Thein Moe (2003) previously used 5% more bitumen to allow for the loss in binder that is left

coated in the mixing chamber walls when the mixture is discharged. Second, the author was

able to use this first slab to familiarise with the usage of the equipment (Wheel Roller

Compactor, machine cutter and coring machine as shown in Figure 5.1). The gradation and

amounts of aggregate for the slabs are shown in Table 5.1.

Figure 5.1 Wheel Roller Compactor (left), Machine Cutter (middle) and Coring Machine (right)

Table 5.1 Gradation of W3B-RCA27 Slab Mix

21


Sieve Size (mm) Weight (g)

W3B-RCA27 mix

Granite RCA

19 - 13.2 2372.09 2326.3013.2 - 6.3 6404.65 6355.196.3 - 3.35 4269.76 3940.053.35 - 1.18 9013.95 -1.18 - 0.3 5693.02 -0.3 - 0.075 3795.35 -

Pan (<0.075) 2846.51 -

Total (g) 47016.86 Weight of Binder (g) 2631.36

The slabs were cast and left for 48 hours. The slabs were then marked for coring. In AASHTO

Designation PP3-94, it is stated in that no sample should be taken from within 50 mm of the

edge of the slab. Markings were made to maximise usage of the slab after incorporating the

discarded edges of the slab. Figure 5.2 shows the layout of the slab for coring purposes.

Figure 5.2 Layout of Slab

A coring machine with a 100mm bit and a 200mm bit were used to core the respective

specimens, while a machine saw cutter was used to cut out the beams.

A total of four 350x50 beams, five 100mm diameter specimens and two 200mm diameter

460

860

350

350

5050

50

Direction of Roll

Dimension of Specimen:860 x 460 x 50 (mm)

N denotes Slab Number100

SN-1SN-2

SN-3SN-4 SN-5

SN-1SN-2

SN-1 SN-2

SN-4SN-3

200

22


specimens were cored from each slab. The specimens were weighed in air and in water to

determine their bulk density and percent compaction relative to the Marshall compaction of

98%. Measurement results are shown in Appendix C.

5.3 Asphalt Content Tester

After creep and rutting tests, some of the specimens were burnt in the Asphalt Content Tester

(also known as Thermolyne oven, as shown in Figure 5.3) as a post test study. It is an oven

equipped with an inbuilt balance which is used to determine binder content. Data such as mass

loss, percentage mass loss, test duration and cycle temperature are dynamically displayed.

Figure 5.3 Asphalt Content Tester

In Sim’s (2003) report, the recorded wet calibration factor used was 0.16%, and Chow (1998)

had used 0.20%. As past results showed that the average binder content using a wet calibration

method was practically the same as the actual binder content, the calibration factor of 0.16%

was adopted. The samples were preheated for an hour at 120 oC in a separate oven and broken

up before spreading them on the heating tray to increase the surface area. This enhances the

efficiency of the burning process. After the burning process, specimens were left to cool down

to room temperature.

23


There were variations in the apparent bitumen content of the specimens. This is due to the non-

homogenous nature of the mixture, and the aggregate to bitumen ratio may be higher in some

samples. This increase in bitumen content is much more obvious with specimens that have

aggregates chipped off, with the encasing bitumen remaining on the specimen. The author

suggests that the surface of the specimens should be reasonably smooth before they are burnt.

This will minimise the error caused by an increase in the ratio bitumen to aggregate due to the

aggregates chipping off.

From the results that are included in Appendix D, the average recovered bitumen content for the

cored specimens was 5.05% and 5.38% for the beam specimens. The apparent bitumen content

of cored specimens burnt at 650 oC was higher than the results from specimens burnt at 450 oC

by 0.57%. This can be due to minerals being burnt off from the aggregates at 650 oC. It is also

coherent with the requirement of a calibration factor for temperature to reduce the apparent

bitumen content of the specimen.

A visual inspection showed that there was a thin black film of carbon covering the surface of the

specimens burnt at 450 oC. This black film is easily removed as it disintegrates into powder

when wiped. Specimens burnt at 650 oC were clean from this black film. The author suggests

that carbon residue can be due to the incomplete burning of bitumen, and further tests can be

made by burning control samples of bitumen and aggregate to work out the calibration factors

due to the temperature.

24


Chapter 6

DYNAMIC CREEP TESTS

6.1 Test Objectives

Dynamic creep tests were carried out on 100mm diameter cored samples from the two test slabs

to assess the performance of the hybrid mix. The test objectives, method and results of the creep

test are provided followed by those of the rutting tests.

6.2 Test Procedures

The dynamic creep test was conducted to assess the creep response of the 100 diameter

specimens from each test slab. The IPC Universal Testing Machine as shown in Figure 6.1 was

used to determine the creep response of the specimens as specified in Australian Standard Method of

Sampling and Testing Asphalt (AS2891.12.1–1995).

Figure 6.1 Universal Testing Machine (UTM) Fitted with Dynamic Creep Test Equipment

The test was conducted in a controlled temperature and stress condition based on the Australian

standard method of sampling and testing asphalt (AS 2891.12.1-1995). LTA’s W3B was

designated as a reference mix to provide comparison benchmarks for the experiment. The

measured height values were input into the computer.

25


The Australian Standard recommends a set of criteria which was used for the creep test. The

creep test criteria are summarised in Table 6.1.

Table 6.1 Dynamic Creep Test Conditions

Parameters Recommended valuesCompressive stress 200 ± 5kPa

Loading period 0.5 ± 0.05secPulse repetition period 2.0 ± 0.05sec

Test temperature 50 ± 0.5OCPre-conditioning time at 50 ± 0.5OC 2 hours

Test termination At 30 000 microstrain OR 40 000 pulse counts

A visual inspection of the integrity of the specimens was conducted. Specimens which had

pieces chipped off or seen to have clear fractures on the surface of the cored sample were not

used. As a result, 3 out of 5 cored specimens were selected per slab for the experiment.

From Ho’s (2003) study, it was found out that cored W3B samples have very low creep

resistance compared to Marshall Samples of the same gradation and bitumen content. This can

be due to the high disturbance brought about by coring the specimens with a coring machine.

This disturbance causes the creation of cracks and micro-fractures to form within the specimen.

6.3 Test Results

Ho’s results for LTA’s W3B were used as a reference mix to provide comparison benchmarks

with the W3B-RCA27 hybrid mix. The data output is listed in Appendix E. The summarised

results are shown in Table 6.2.

26


Table 6.2 Dynamic Creep Test Results from This Study and Ho (2003)

Tester Mix Specimen Accum. Strain (microstrain,

fn)

Creep Stiffness (MPa)

Pulse Count @ 10000 fn

Pulse Count @ 30000 fn

This Study(Lee, 2009)

W3B RCA27

S1-1 30255 5.6 53 368S1-2 30275 5.5 37 274S1-5 30235 5.3 55 381S2-2 30122 5.5 51 530S2-3 30107 5.6 31 433S2-4 30077 5.5 44 541

Ho, 2003

W3B-PEN 60/70

S4-1 67628 2.58 29 198S4-2 76436 1.44 30 261S5-1 85646 2.19 40 193S5-2 78746 2.36 30 178S6-1 73579 2.54 35 379S6-2 67407 2.76 29 354

27


CHAPTER 7

RUTTING TEST

7.1 Introduction

The rutting test was conducted on four cored 200mm diameter specimens to evaluate the rut

response of the W3B hybrid mix. All four 200mm specimens are in good quality and are thus

used for the Rutting tests. The experiment was conducted on a wheel tracking machine (see

Figure 7.1) based on the procedure described in BS598: Part 110: 1996 as well as improvements

made by past studies.

Figure 7.1 Wheel Tracking Machine

7.2 Track Rate and Relative Rut Depth

Track rate represents the rate at which the rut depth increases with time under repeated passes of

a loaded wheel (in mm/h). For each tested specimen, the track rate should be calculated using

the following formula:

15

900

TTR = (7.1)

28


where,

TR = Track Rate (mm/h)

T15 = Time, in minute, for rut depth to reach 15 mm

When rut depth of 15 mm is not reached by 45 minutes, an alternative formula is used to relate

the track rate of the specimen to time:

60×=t

R T

RRDT (7.2)

where,

RRD = Relative Rut Depth (mm)

T1 = Test time (minute)

7.3 Test Procedure

A wooden block encases the specimen which is padded up with hard acrylic panels, as shown in

Figure 7.1. The temperature of the specimen is monitored via a sensor coated with heat transfer

silicon inserted into a 15mm hole bored into the specimen.

A thin layer of granite fines is spread on the length of rutting area to prevent bitumen from

damaging the wheel and affecting the experiment. Through a firm schedule shown in Appendix

F it was possible to complete testing four specimens in one day.

29


7.4 Test Results

Figure 7.2 Cored Specimens S1-1 and S2-2 After Rutting Test

The tested specimens are shown in Figure 7.2. The summary of the results by the author as well

as those of previous rutting tests performed by Ang (2008), Ho (2003) and Ie (2000) are shown

in Table 7.1. The data output is shown in Appendix G.

Table 7.1 Rutting Test Results

Tester Slab Specimen Relative Rut Depth (mm)

Track Rate (mm/h)

Bulk density (kg/

m3)Lee, 2009 W3B RCA27 S1-1 2.60 3.47 2276.5

W3B RCA27 S1-2 1.92 2.56 2284.8

W3B RCA27 S2-1 2.71 3.61 2270.0

W3B RCA27 S2-2 2.71 3.61 2271.8

Average 2.49 3.31 2275.8Ang, 2008 W3B RCA37

(Average)2.47 3.29 2198.0

W3B RCA24 (Average)

1.38 1.84 2190.0

Ho, 2003 PEN 60/70 6.91 9.21 -　PEN 60/70 6.01 8.01 -　PEN 60/70 8.15 10.87 -　

Ie, 2000 W3B (Average) 4.00 5.33 2285.0

30


Chapter 8

CONCLUSIONS AND RECOMMENDATIONS

8.1 Review of Results

The objective of this study is to evaluate the performance of a hybrid mix of the Land Transport

Authority (LTA)’s W3B with partial substitution of Recycled Concrete Aggregate (RCA)

through creep performance and rutting tests.

The optimum binder content of the hybrid mix W3B-RCA27 was determined according to

LTA’s Marshall Design Criteria for W3B’s wearing course. A value of 5.3% binder content was

used for the hybrid mixes, and Ho’s (2003) W3B slab specimens were used as benchmark for

comparison in this research. Two slabs of this mix were fabricated. Samples were cored from

the slabs for performance testing. The individual performance values obtained would

correspond to the values to the fabricated slab on a whole.

The asphalt content tester results suggest that the bitumen content was higher than 5.3%. This

can be due to the burning off of minerals and fines in RCA. Further tests can be made to

determine the actual amount of RCA material burnt off in order to better assess the actual

bitumen content.

The results from the creep tests, on average, have higher creep stiffness but lower accumulated

strain than those obtained by Ho (2003). As the hybrid mix has higher pulse counts to failure

but a lower accumulated strain, the author suggests that the hybrid mix is not as stiff as Ho’s

(2003) W3B mix, but is more ductile and able to take more repetitions of pulse counts before

failure. The higher creep stiffness can be appropriated to the high density of the hybrid mix as

compared to Ho’s (2003). The hybrid mix is considerably weaker than Ho’s W3B-PEN 60/70

mix, and fails at a lower accumulated strain.

31


The rutting tests showed that the hybrid mix has a lower track rate, exhibiting higher rutting

resistance compared to the results by Ho (2003) which consisted of pure granite aggregate. The

specimen (S1-2) with the highest bulk density gave the lowest track rate. This can be due to the

specimen being heavily compacted during the fabrication, which keeps the aggregate highly

interlocked and thus resistant to rutting. The graphs in Appendix G show that the rutting rate

decreases with time and forms a gentle slope near the end of the 45 minutes of testing. This

could be due to the initial shifting of the aggregate in the rutting specimen, causing the angular

aggregates to interlock even further near the end to form a stiffer structure.

8.2 Recommendations

The author would like to offer the following recommendations to reinforce the findings attained

in this research and to further verify the feasibility of RCA application in HMA.

The current rutting results suggest that the hybrid specimen has a better rutting performance

compared to conventional W3B, but shows a lower accumulated strain capability. Research can

be done to understand the durability of the wearing course in Singapore and whether the

pavements are first worn out by creep or rutting. There will be value-add in terms of designing a

hybrid that would make up for the weaker parameter and thus increases the longevity of the

wearing course of pavements.

The bulk density of the slab specimens implies that they have been over compacted. Better

knowledge of the newly acquired plate compactor will help to fabricate slabs with it and to

assess the differences in the Plate Compactor and Wheel Roller Compactor. Further research can

be done to increase the quality of the fabrication of large slabs in future studies.

32


References

Ang, C. H. (2008). Performance Characteristics of Hot-Mix Asphaltic Concrete with Recycled

PCC Aggregate, Bachelor of Engineering Final Year Project Report, School of Civil and

Environmental Engineering, Nanyang Technological University, Singapore [Unpublished]

Cheong, C. M. (2007). Performance Evaluation of Recycled Concrete Aggregate in Hot-Mix

Asphalt, Bachelor of Engineering Final Year Project Report, School of Civil and Environmental

Engineering, Nanyang Technological University, Singapore [Unpublished]

Chow, C. G. (1998). Evaluation of the Asphalt Content Tester, Bachelor of Engineering Final

Year Project Report, School of Civil and Structural Engineering, Nanyang Technological

University, Singapore [Unpublished]

FHWA (2003). Summary of California Recycled Concrete Aggregate Review, Recycling,

Pavements, U.S. Department of Transportation, Federal Highway Administration (in

http://www.fhwa.dot.gov/pavement/recycling/rcaca.cfm; retrieved August 2008).

FHWA (2006). Reclaimed Concrete Material, US Department Of Transportation, Federal

Highway Administration (http://www.tfhrc.gov/hnr20/recycle/waste/index.htm; retrieved

August 2008).

Focus (April 2004). Recycled Concrete Study Identifies Current Uses, Best Practices, (in http://

www.tfhrc.gov/FOCUS/apr04/01.htm; retrieved August 2008).

Hidehito Ie (2000). Rutting Characteristics of Asphalt Concrete Mix, Bachelor of Engineering

Final Year Project, School of Civil and Structural Engineering, Nanyang Technological


Ho, S. S. (2003). Fatigue Characteristics of Hot-Mix Asphalt Concrete, Bachelor of Engineering

33


http://www.tfhrc.gov/FOCUS/apr04/01.htm

http://www.tfhrc.gov/FOCUS/apr04/01.htm

http://www.tfhrc.gov/hnr20/recycle/waste/index.htm

http://www.fhwa.dot.gov/pavement/recycling/rcaca.cfm

Final Year Project, School of Civil and Environmental Engineering, Nanyang Technological


LTA (2009) Code of Practice for Works on Public Streets, March 2009 Edition Revision R1 (in

http://www.lta.gov.sg/dbc/doc/guideline/COP%20for%20Works%20on%20Public

%20Streets_Mar09Edrev1.pdf; retrieved March 2009)

NEA (2002). Waste Minimisation Section - Formation of Waste Minimisation Section (in http://

app.nea.gov.sg/cms/htdocs/article.asp?pid=1460 ; retrieved September 15, 2008).

NEA (2006). Semakau Landfill & Tuas Marine Transfer Station, (in

http://www.nea.gov.sg/cms/esd/brochure/TMTS.pdf ; retrieved September 15, 2008).

NEA (2008). Waste Statistics and Recycling Rate for 2007 (in http://app.nea.gov.sg/cms/htdocs/

article.asp?pid=2706; retrieved August 2008).

Phoon, Y. L. (1998). Resilient Modulus Characteristics of Stone Mastic Asphalt, Bachelor of

Engineering Final Year Project, School of Civil and Structural Engineering, Nanyang

Technological University, Singapore [Unpublished]

Sim, Y. M. (2003). Fatigue Characteristics of Hot-Mix Asphalt Concrete, Bachelor of

Engineering Final Year Project, School of Civil and Environmental Engineering, Nanyang

Technological University, Singapore [Unpublished]

Thein Moe (2005). Rutting Characteristics of Asphalt Concrete Mix, Master of Science

(Transportation Engineering) Dissertation, School of Civil and Environmental Engineering,

Nanyang Technological University, Singapore [Unpublished]

34


http://app.nea.gov.sg/cms/htdocs/article.asp?pid=2706


http://www.nea.gov.sg/cms/esd/brochure/TMTS.pdf



http://www.lta.gov.sg/dbc/doc/guideline/COP%20for%20Works%20on%20Public%20Streets_Mar09Edrev1.pdf

http://www.lta.gov.sg/dbc/doc/guideline/COP%20for%20Works%20on%20Public%20Streets_Mar09Edrev1.pdf

APPENDIX A:

Results for Change in Gradation of Recovered W3B-RCA Specimens


Tables of Recovered W3B Gradation

By Mass* (g)

Sieve Size (mm) W3B(g) W3B-1(g) W3B-2(g)

19 0 0 013.2 120 113.8 102.96.3 324 289.6 295.33.35 216 195.5 184.91.18 228 207.7 224.70.3 144 58.2 57.6

0.075 96 157.7 142.4

0 72 50.9 57.7

Total Weight 1200 1073.4 1065.5Total Coarse 660 598.9 583.1

19 - 13.2 Lost (%) - 5.17 14.2513.2 - 6.3 Lost (%) - 10.62 8.866.3 - 3.35 Lost (%) - 9.49 14.403.35 - 1.18 Lost (%) - 8.90 1.451.18 - 0.3 Lost (%) - 59.58 60.000.3 - 0.075 Lost (%) - -64.27 -48.33

Pan Lost (%) - 29.31 19.86Total Coarse Lost (%) - 9.26 11.65

Total Fines (g) 540 474.5 482.4Total Fines Lost (g) - 65.5 57.6

Total Fines Lost (%) - 12.13 10.67*negative values in Lost (%) mean there is a gain in mass

Volume Passing (%)

Sieve Size (mm) W3B(cm^3) W3B-1-2(cm^3) W3B-2-2(cm^3)

19 100.00 100.00 100.0013.2 90.00 89.40 90.346.3 63.00 62.42 62.63

3.35 45.00 44.21 45.271.18 26.00 24.86 24.190.3 14.00 19.43 18.78

0.075 6.00 4.74 5.42


Recovered W3B Gradations In Comparison with Specifications

0

10

20

30

40

50

60

70

80

90

100

0.01 0.1 1 10 100Aggregate Size (mm)

Vol

ume

Pas

sing

(%)

Upper Limit

Lower Limit

W3B-1(cm^3)

W3B-2(cm^3)


Tables of Recovered W3B-RCA53 Gradation

By Mass* (g)

Sieve Size (mm) W3B-RCA53 (g) W3B-RCA53-1 (g) W3B-RCA53-2 (g)19 0 0 0

13.2 112.59 96.50 147.10 6.3 303.98 266.90 218.20

3.35 202.66 156.00 157.00 1.18 228 225.80 241.20 0.3 144 66.30 59.40

0.075 96 140.30 224.60 0 72 58.80 19.40

Total Weight 1159.23 1010.60 1066.90 Total Coarse 619.23 519.40 522.30

19 - 13.2 Lost (%) - 14.29 -30.65 13.2 - 6.3 Lost (%) - 12.20 28.22 6.3 - 3.35 Lost (%) - 23.02 22.53

3.35 - 1.18 Lost (%) - 0.96 -5.79 1.18 - 0.3 Lost (%) - 53.96 58.75

0.3 - 0.075 Lost (%) - -46.15 -133.96 Pan Lost (%) - 18.33 73.06

Coarse Lost (%) - 16.12 15.65 Total Fines 540 491.20 544.60

Total Fines Lost (g) - 48.80 -4.60 Total Fines Lost (%) - 9.04 -0.85

*negative values in Lost (%) mean there is a gain in mass

Volume Passing (%)

Sieve Size (mm)

W3B-RCA53 (cm^3) W3B-RCA53-1 (cm^3) W3B-RCA53-2 (cm^3)

19 100.00 100.00 100.00 13.2 90.00 90.36 86.08 6.3 63.00 63.70 65.42

3.35 45.00 48.12 50.56 1.18 26.00 26.00 28.17 0.3 14.00 19.50 22.65

0.075 6.00 5.76 1.80


Recovered W3BRCA53 Gradations In Comparison with Specifications

0

10

20

30

40

50

60

70

80

90

100

0.01 0.1 1 10 100Aggregate Size

Vol

ume

Pas

sing

(%)

Upper Limit

Lower Limit

W3B-RCA53-1(cm^3)

W3B-RCA53-2(cm^3)


APPENDIX B:

Marshall Specimen Mass-Volume Relationship Table


Spe

cim

en N

o.1

23

45

67

89

Mas

s of

Spe

cim

en in

Air

, g12

45.1

1239

.812

39.2

1232

.012

38.7

1242

.012

39.5

1246

.112

47.5

Mas

s of

Spe

cim

en in

Wat

er, g

694.

069

5.6

692.

668

5.6

689.

869

4.9

696.

369

8.4

704.

1

Vol

ume,

cm

355

1.1

544.

254

6.6

546.

454

8.9

547.

154

3.2

547.

754

3.4

Ave

rage

Thi

ckne

ss, m

m70

.49

68.4

669

.13

68.2

469

.25

68.6

367

.57

68.7

868

.16

Bin

der

abso

rpti

on, %

0.7

0.7

0.7

0.7

0.7

0.7

0.7

0.7

0.7

Bin

der

cont

ent,

%4.

754.

754.

755.

005.

005.

005.

255.

255.

25

Den

sity

of

bind

er, g

/cm

31.

021.

021.

021.

021.

021.

021.

021.

021.

02

Mas

s of

bin

der,

g59

.158

.958

.961

.661

.962

.165

.165

.465

.5M

ass

of a

ggre

gate

, g11

86.0

1180

.911

80.3

1170

.411

76.8

1179

.911

74.4

1180

.711

82M

ass

of a

bsor

bed

bind

er, g

8.3

8.3

8.3

8.2

8.2

8.3

8.2

8.3

8.3

Mas

s of

eff

ecti

ve b

inde

r, g

50.8

50.6

50.6

53.4

53.7

53.8

56.8

57.1

57.2

Vol

ume

of b

inde

r, cm

358

.057

.757

.760

.460

.760

.963

.864

.164

.2

Vol

ume

of a

bsor

bed

bind

er, c

m3

8.1

8.1

8.1

8.0

8.1

8.1

8.1

8.1

8.1

Vol

ume

of e

ffec

tive

bin

der,

cm3

49.8

49.6

49.6

52.4

52.6

52.8

55.7

56.0

56.1

Bul

k de

nsit

y of

agg

rega

te, g

/cm

32.

532.

532.

532.

532.

532.

532.

532.

532.

53M

ass

of a

ggre

gate

, g11

86.0

1180

.911

80.3

1170

.411

76.8

1179

.911

74.4

1180

.711

82B

ulk

volu

me

of a

ggre

gate

, g/

cm3

468.

846

6.8

466.

546

2.6

465.

146

6.4

464.

246

6.7

467.

2E

ffec

tive

vol

. of

aggr

egat

e, g

/cm

346

0.6

458.

645

8.4

454.

645

745

8.2

456.

145

8.6

459.

1

Vol

ume

of a

ir, c

m3

32.5

27.8

30.5

31.4

31.1

27.9

23.2

25.0

20.1

Bul

k de

nsit

y, g

/cm

32.

262.

282.

272.

252.

262.

272.

282.

282.

30

Max

imum

theo

reti

cal d

ensi

ty, g

/cm

32.

402.

402.

402.

392.

392.

392.

382.

382.

38

Voi

ds in

tota

l mix

, VT

M, %

5.90

5.11

5.57

5.75

5.67

5.11

4.28

4.56

3.71

Voi

ds in

min

eral

agg

rega

te, V

MA

, %14

.914

.214

.615

.315

.314

.814

.514

.814

.0

Voi

ds f

ille

d w

ith

bind

er, V

FB

, %60

.564

.161

.962

.562

.865

.470

.669

.273

.6


APPENDIX C:

Measurements of Cored Specimens


100m

m D

iam

eter

Cor

ed S

ampl

e

Sla

b N

umbe

rN

o.W

eigh

t in

Air

(kg

)W

eigh

t in

Wat

er (

kg)

Vol

ume

Bul

k de

nsit

y (k

g/m

3 )

Per

cent

age

com

pact

ion

(%)

1st

read

ing

(mm

)

2nd

read

ing

(mm

)

3rd

read

ing

(mm

)

Ave

rage

th

ickn

ess

(mm

)(m

3 ) X

10-3

S1

10.

946

0.52

8 0.

417

2266

.298

.11

55.5

5 55

.71

56.1

9 55

.82

20.

922

0.51

9 0.

403

2285

.698

.94

54.4

5 54

.34

54.7

2 54

.50

30.

895

0.51

1 0.

384

2328

.310

0.79

53.6

6 53

.00

53.2

4 53

.30

40.

886

0.50

4 0.

381

2323

.510

0.59

53.7

6 53

.05

52.5

8 53

.13

50.

905

0.51

6 0.

389

2328

.110

0.78

53.1

2 53

.58

52.9

3 53

.21

S2

10.

857

0.48

6 0.

370

2313

.910

0.17

50.5

7 50

.23

50.2

5 50

.35

20.

867

0.48

7 0.

380

2282

.698

.81

51.7

2 51

.73

52.4

5 51

.97

30.

866

0.49

2 0.

374

2314

.110

0.18

50.5

3 49

.89

50.7

7 50

.40

40.

842

0.47

7 0.

365

2306

.899

.86

49.4

1 49

.65

50.0

3 49

.70

50.

868

0.49

1 0.

377

2301

.099

.61

52.6

7 51

.31

52.6

0 52

.19

200m

m D

iam

eter

Cor

ed S

ampl

e

Sla

b N

umbe

rN

o.W

eigh

t in

Air

(kg

)W

eigh

t in

Wat

er (

kg)

Vol

ume

Bul

k de

nsit

y (k

g/m

3 )

Per

cent

age

com

pact

ion

(%)

1st

read

ing

(mm

)

2nd

read

ing

(mm

)

3rd

read

ing

(mm

)

Ave

rage

th

ickn

ess

(mm

)(m

3 ) X

10-3

S1

14.

305

2.41

4 1.

891

2276

.598

.55

63.3

0 61

.95

62.1

2 62

.46

24.

096

2.30

3 1.

793

2284

.898

.91

61.7

6 60

.30

56.9

0 59

.65

S2

13.

463

1.93

7 1.

525

2270

.098

.27

49.8

8 50

.73

50.3

5 50

.32

23.

799

2.12

7 1.

672

2271

.898

.35

55.4

4 56

.10

54.6

6 55

.40


APPENDIX D:

Results from Asphalt Content Tester


Res

ults

fro

m A

spha

lt C

onte

nt T

este

r

Cor

e S

ampl

e N

o.D

urat

ion

(min

)S

ampl

e W

eigh

t (g)

Wei

ght

Los

s (g

)P

erce

nt L

oss

(%)

Bin

der

Con

tent

(%

)Te

mpe

ratu

re

(o C)

Cal

ibra

tion

Fac

tor

for

Tem

pera

ture

Est

imat

ed

Bin

der

Con

tent

(%

)S

1 C

OR

E 1

8291

551

.15.

58

5.26

450

0.33

5.1

S2

ED

GE

9319

7110

5.1

5.33

5.

1845

00.

155.

02S

1 C

OR

E 2

3193

157

.26.

14

5.82

650

0.32

5.66

S2

CO

RE

235

863

52.7

6.11

5.

7665

00.

355.

6A

vera

ge B

inde

r C

onte

nt =

(5.

26%

+ 5

.18%

+ 5

.82%

+ 5

.76%

) / 4

= 5

.505

%

Bea

m N

o.D

urat

ion

(min

)S

ampl

e W

eigh

t (g)

Wei

ght

Los

s (g

)P

erce

nt L

oss

(%)

Bin

der

Con

tent

(%

)Te

mpe

ratu

re

(o C)

Cal

ibra

tion

Fac

tor

for

Tem

pera

ture

Est

imat

ed

Bin

der

Con

tent

(%

)S

1-1

105

2577

137.

05.

32

5.20

450

0.12

5.04

S1-

312

629

3316

2.4

5.56

-*

450

-*-*

S1-

488

2375

133.

05.

60

5.47

450

0.13

5.31

S2-

188

2457

129.

05.

25

5.13

450

0.12

4.97

S2-

211

025

1713

9.4

5.54

5.

4545

00.

095.

29S

2-3

-*27

1915

6.6

5.76

5.

6545

00.

115.

49S

2-4

117

2638

144.

45.

47

5.39

450

0.09

5.23

*Val

ues

not o

btai

ned

due

to b

reak

dow

n in

asp

halt

con

tent

test

erA

vera

ge B

inde

r C

onte

nt =

5.3

8%


APPENDIX E:

Data Output from Dynamic Creep Test














APPENDIX F:

Time Schedule for Rutting Test


56

78

910

11

12

13

14

15

16

17

18

Hours

Heatin

g u

p O

ven

with

Sam

ple

(15m

ins)

Heatin

g u

p o

f S

am

ple

in

Ove

n

Tra

nsfe

r S

am

ple

to M

/C,

Heat

for

1h

r

Ru

n T

est

Com

ple

te T

est

Heatin

g u

p o

f S

am

ple

in

Ove

n

Tra

nsfe

r S

am

ple

to M

/C,

Heat

for

1h

r

Ru

n T

est

Com

ple

te T

est

Heatin

g u

p o

f S

am

ple

in

Ove

n

Tra

nsfe

r S

am

ple

to M

/C,

Heat

for

1h

r

Ru

n T

est

Com

ple

te T

est

Heatin

g u

p o

f S

am

ple

in

Ove

n

Tra

nsfe

r S

am

ple

to M

/C,

Heat

for

1h

r

Ru

n T

est

Com

ple

te T

est

Sample 1 Sample 2 Sample 3 Sample 4P

roje

ct T

ime

Lin

e

Not

es:

T

ime

line

ass

umes

a s

tart

ing

time

of m

anua

l wor

k at

9.0

0am

,

Ove

ns a

re ti

med

to s

tart

at 7

.45a

m a

nd 8

.00a

m

Tim

e to

hea

t up

sam

ple

in o

ven

is 3

hrs,

tim

e fo

r ac

tual

test

is 4

5min

utes

A

n ex

tra

15m

inut

es is

take

n in

to c

onsi

dera

tion

E

stim

ated

tim

e of

com

plet

ion

is 5

.00p

m


APPENDIX G:

Data Output from Rutting Test


Tim

eR

utti

ng D

epth

(m

m)

Tim

eR

utti

ng D

epth

(m

m)

00.

00

232.

31

10.

89

242.

35

21.

31

252.

41

31.

51

262.

41

41.

60

272.

41

51.

75

282.

41

61.

81

292.

41

71.

91

302.

41

82.

00

312.

44

92.

01

322.

51

102.

01

332.

51

112.

07

342.

51

122.

10

352.

51

132.

10

362.

51

142.

11

372.

51

152.

21

382.

51

162.

21

392.

51

172.

21

402.

51

182.

22

412.

51

192.

31

422.

60

202.

31

432.

60

212.

31

442.

60

222.

31

452.

60

Sla

b S

am

ple

S1

-1

0

0.51

1.52

2.53

05

101

52

025

30

35

40

45

Tim

e (

min

)Rutting Depth (mm)


Tim

eR

utti

ng D

epth

(m

m)

Tim

eR

utti

ng D

epth

(m

m)

00.

0023

1.51

10.

1824

1.61

20.

4125

1.61

30.

6126

1.61

40.

7227

1.64

50.

8328

1.71

60.

9029

1.71

71.

0130

1.71

81.

0131

1.71

91.

1132

1.73

101.

1233

1.81

111.

2134

1.81

121.

2535

1.81

131.

3136

1.81

141.

3137

1.81

151.

3138

1.81

161.

3539

1.83

171.

4040

1.90

181.

4041

1.90

191.

4142

1.90

201.

4743

1.90

211.

5144

1.90

221.

5145

1.92

Sla

b S

am

ple

S1

-2

0

0.51

1.52

2.53

05

10

15

20

25

30

35

40

45

Tim

e (

min

)

Rutting Depth (mm)


Tim

eR

utti

ng D

epth

(m

m)

Tim

eR

utti

ng D

epth

(m

m)

00.

0023

2.30

10.

7924

2.31

21.

0125

2.41

31.

3726

2.41

41.

5127

2.41

51.

6128

2.41

61.

7129

2.41

71.

7430

2.46

81.

8931

2.51

91.

9132

2.51

101.

9633

2.51

112.

0134

2.51

122.

0135

2.53

132.

1136

2.61

142.

1137

2.61

152.

1138

2.61

162.

1339

2.61

172.

2140

2.61

182.

2141

2.62

192.

2142

2.71

202.

2743

2.71

212.

3044

2.71

222.

3045

2.71

Sla

b S

am

ple

S2

-1

0

0.51

1.52

2.53

05

10

15

20

25

30

35

40

45

Tim

e (

min

)

Rutting Depth (mm)


Sla

b S

am

ple

S2

-2

0

0.51

1.52

2.53

05

10

15

20

25

30

35

40

45

Tim

e (

min

)

Rutting Depth (mm)

Tim

eR

utti

ng D

epth

(m

m)

Tim

eR

utti

ng D

epth

(m

m)

00.

00

232.

31

10.

76

242.

36

21.

13

252.

41

31.

33

262.

41

41.

52

272.

41

51.

60

282.

41

61.

71

292.

43

71.

81

302.

51

81.

83

312.

51

91.

91

322.

51

101.

93

332.

51

112.

01

342.

51

122.

01

352.

51

132.

10

362.

60

142.

10

372.

60

152.

10

382.

60

162.

21

392.

60

172.

21

402.

60

182.

21

412.

61

192.

21

422.

61

202.

31

432.

61

212.

31

442.

63

222.

31

452.

71


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