1 《 road engineering materials 》 chapter2 asphalt materials

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Page 1: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

1

《 Road Engineering Materials 》

Chapter2 Asphalt materials

Page 2: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

2

Aggregates mixture and design1.3——the method of grading design: trial and error method

6.04~8 13.210.80.075

5.08~16—11.60.15

7.012~22—12.40.3

80518~30—16.00.6

12.024~41—22.51.18

13.536~53—24.02.62.36

18.570~88——41.79.5

2.5 95~100——5.213.2

0100———16

mid-value of

Envelope in C.R.

( % )

grading

Envelope in P.

( % )

Fine (C) retained

in C.R.(%)

Medium (B) retained

in C.R.(%)

Coarse (A) retained in

C.R.(%)

Mesh size( mm )

21.048~68—1.650.54.75

—1.2pan 86.8 6.0

Page 3: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

3

7162~8010010034.513.2

64~870.5——0.075

1510~209411.0—0.3

1615~279723.0—0.6

2720~3410036.0—1.18

3728~4610058.7—2.36

4838~5810077.94.64.75

6252~7210093.819.89.5

82. 575~9010010061.516

97. 595~1001001009719.

10010010010010026.5

midenvlopeenvelopefillerchipCrushed agg.

Objective envelope(%)Passing for each kind aggregate (%)Sieve size( mm)

106~1492——0.15

Example of Aggregate Mixture Design

(65.5) (29)

Page 4: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

4

Synthesis gradation

4~870.5——0.075

6~1492——0.15

10~209411.0—0.3

15~279723.0—0.6

20~3410036.0—1.18

28~4610058.7—2.36

38~5810077.94.64.75

52~7210093.819.89.5

62~8010010034.513.2

75~9010010061.516

95~1001001009719.

10010010010026.5

envelopeFiller ×10.9Chip ×46.8Crushed agg.×42.3

Objective envelope( % )不同规格集料各筛上通过量( %)Sieve size

( mm)

7.7

10.0

17.3

21.4

27.7

38.4

49

63.2

72.3

83.7

98.7

100

results

1.9

8.4

14.6

26.0

41.0

42.3

5.1

10.8

16.8

27.5

36.5

43.9

46.8

46.8

46.8

46.8

7.7

10.0

10.2

10.6

10.9

10.9

10.9

10.9

10.9

10.9

10.9

10.9

Page 5: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

5

Main topics

Introduction Petroleum Asphalt2.1

Technical Property of Petroleum Asphalt2.2

Polymer Modified Asphalt2.3

Other Asphalt2.4

Page 6: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Petroleum asphaltPetroleum asphalt2.1

Page 7: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

7

——IntroductionOrganic cementing materials

Tars Pitches

Natural deposits Petroleum asphalts

Rockasphalts

Asphalt cement(solid or semi-solid)

Cutback asphalts(liquid)

Emulsified asphalts(liquid)

Blown asphalt(semi-solid)

Slow curing Medium curing Rapid curing

Petroleum asphalt2.1

Petroleum Asphalt

Seeasphalts

Asphalts (Bitumen)

Lake asphalts

Page 8: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

8

Petroleum refinery

Residual matter

Air

Air-blownasphalt

Asphaltcement

DistillatesGasoline, kerosene, Diesel oil, etc

Rapid-curingCutback asphalt

Asphaltcement

Gasoline

Medium-curingCutback asphalt

Asphaltcement

Kerosene

Slow-curingCutback asphalt

Asphaltcement

Diesel oil

Emulsifiedasphalt

Asphaltcement

Water

Emulsifyingagent

ProcessingStill

——Asphalt processing

Petroleum asphalt2.1

Page 9: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

9

——Components of Petroleum Asphalt(沥青组分)Petroleum asphalt2.1

Asphalt

Saturated

(饱和分)

正庚烷沉淀

Asphaltene

(沥青质)

不可溶解部分

Soft Asphaltene

(软沥青质)

可溶解部分

Aromatics

(芳香分) Resin

(胶质)

正庚烷冲洗 甲苯冲洗 甲苯 / 乙醇冲洗

Page 10: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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四组分:饱和分( Saturated )芳香分( Aromatics )胶质( Resin )沥青质( Asphaltene ) ( S, Ar, R, As )

Petroleum asphalt2.1

——Components of Petroleum Asphalt (沥青组分)

Page 11: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

11

sol-gel type Gel type

Petroleum asphalt2.1

——Colloid structure of Petroleum Asphalt (沥青的胶体结构)

sol type

14 4 4

33

12 2

Diagram of Colloid structure of Petroleum Asphalt

1- Saturated ; 2-Aromatics ; 3- Resin ; 4-Asphaltene

Page 12: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

12

Petroleum asphalt2.1

——Colloid structure of Petroleum Asphalt (沥青的胶体结构)

Colloid structure sol type sol-gel type gel type

P.I <-2 -2~+2 >+2

Page 13: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

13

Technical Property of Petroleum Asphalt ——introduction

2.2

main properties of asphalt

physical properties

密度 体积膨胀系数

介电常数

Viscosity

(黏滞性)

黏 度 稠 度

low temperature property

延性 脆性

temperature susceptibility

针入度指

数( PI )

Adhesiveness黏附性

Durability耐久性

visco-elastic粘弹性

Page 14: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

14

Relative density (25℃/25 )℃ = Asphalt density (15 ℃) ×0.996

密度瓶

Technical Property of Petroleum Asphalt ——Density

2.2

m m

m m m m

沥青+瓶 瓶沥青 水

瓶 满水 瓶 瓶 沥青 水 瓶+沥青

-

( - )-( - )

Weigh the following mass successively:

1. m 瓶

2. m 瓶 + 满水

3. m 瓶 + 沥青

4. m 瓶 + 沥青 + 水

Page 15: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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2.2 Technical Properties of Petroleum Asphalt

Page 16: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Across the screen the autumn moonAcross the screen the autumn moon

stares coldly from the sky;stares coldly from the sky;

With silken fan I sit and flickWith silken fan I sit and flick

the fireflies sailing by,the fireflies sailing by,

The night grows colder every hour,——The night grows colder every hour,——

it chills me to the heartit chills me to the heart

To watch the Spinning Damsel To watch the Spinning Damsel

from the herd boy far apart.from the herd boy far apart. By Du MuBy Du Mu

银烛秋光冷画屏, 轻罗小扇扑流萤。 银烛秋光冷画屏, 轻罗小扇扑流萤。 天阶夜色凉如水,坐看牵牛织女星。天阶夜色凉如水,坐看牵牛织女星。 —— —— 杜牧杜牧

Page 17: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Technical Property of Petroleum Asphalt ——Viscosity ( 黏滞性 )

2.2

Viscosity means a capability that the particles of asphalt material resist shearing deformation under external force.

dvF A

dy ,

F dv

A dy 当

得到表征动力粘度的公式:

=

动力黏度与密度之比为运动黏度:

表示沥青层间的速度变化梯度(剪变率)为一个单位时,单位面积沥青可承受的的内磨阻力。

Page 18: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

18

Viscosity can be measured by different methods.

Technical Property of Petroleum Asphalt ——Viscosity ( 黏滞性 )

2.2

Measurement on viscosity

真空减压毛细管法

动力黏度 ( Pa.S )

毛细管法

运动黏度( mm2/S )

布洛克菲尔德粘度计法

表观黏度( Pa.S )

相对黏度

针入度 ( 0.1mm )

软化点(℃)

稠 度 高温稳定性

Page 19: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Relative viscosity such as penetration is consistency rather than viscosity actually, which means a standard needle penetrates depth (0.1mm) into the asphalt sample under specified conditions (test temperature 25℃, mass of standard needle 100g, time of penetration 5s). So penetration can be expressed as P25℃,100g,5s.

Technical Property of Petroleum Asphalt ——Relative viscosity: Penetration (针入度)

2.2

Schematic of penetration test Penetrometer

The lower of penetration value, the higher consistency is.Penetration not only expresses the consistency of asphalt sample, but it is the basis of asphalt grading. The greater of the value of penetration, the higher asphalt grade is.

Page 20: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Softening point expresses the specified softening level (℃: TR&B) of asphalt sample when heated under some specified conditions (e.g. rate of temperature: 5 /min.).℃

The higher softening point, the better of performance at high temperature asphalt is.

Softening point can be considered as a temperature under same consistency, while penetration is a consistency under same temperature condition.

Technical Property of Petroleum Asphalt ——Relative viscosity: Softening point ( 软化点 )

2.2

Schematic of softening point testSoftening point test apparatus

Page 21: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

21

Ductility is the total plastic deformation (mm) of asphalt sample when it is stretched under specified condition (e.g. temperature: 15℃ or10 , drawing ℃speed: 5cm/min.).

The greater ductility at lower temperature, the better low temperature performance of asphalt is.

Technical Property of Petroleum Asphalt ——properties at low temperature: Ductility (延度)

2.2

Test specimen Demonstration of ductility test

Page 22: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Asphaltic material may vary from solid to liquid, depending on the temperature. This characteristic is known as temperature susceptibility.

Temperature susceptibility can be expressed as penetration index (PI: 针入度指数 ) and index of penetration and viscosity number (PVN :针入度黏度指数 ).

The former indicates the temperature susceptibility of asphalt under softening point, while the latter indicates the property above the softening pointer.

Technical Property of Petroleum Asphalt ——Temperature susceptibility (感温性)

2.2

Page 23: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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PI can be expressed as:

21

21 lglg

TT

PPA

Technical Property of Petroleum Asphalt ——Temperature susceptibility (感温性)

2.2

10501

30

API Here:

PI determining

(1) When temperature of asphalt is at the softening point, penetration of the asphalt is nearly 800(0.1mm) at this temperature, So

which ( A ) is coefficient of penetration and

temperature.

25T

Plg800lg

B&R

25,100g,5s

A

Page 24: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

24

(2) Measuring several penetrations under different temperature condition (such as 15℃, 20 ℃, 25 ℃, 30 ℃, etc), through the mathematical regression, the coefficient of penetration and temperature (A) is find out. (Note the regression coefficient should not less than 0.997)

(3) Through the monograph to find PI directly.

Technical Property of Petroleum Asphalt ——Temperature susceptibility (感温性)

2.2

Page 25: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Significance of PI Expressing the degree of temperature susce

ptibility under softening point; The greater PI, the lower temperature susce

ptibility of asphalt is; Division types of colloid structure of asphalt: PI<-2, sol type

PI>+2, gel type

PI= -2~ +2, sol-gel type

Technical Property of Petroleum Asphalt ——Temperature susceptibility (感温性)

2.2

Page 26: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Equivalent softening point: means the corresponding temperature when penetration is 800(0.1mm), which shows the high temperature performance of asphalt.

Equivalent breaking point: the corresponding temperature when penetration is 1.2(0.1mm), which reflects the low temp. performance.

800

lg800 KT

A

Technical Property of Petroleum Asphalt ——Temperature susceptibility (感温性)

2.2

1.2

lg1.2 KT

A

Page 27: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

27

When asphalt mixes with aggregate particles, asphalt forms film on the particles. Adhesiveness represents connection degree of this thin film. The higher degree, the better adhesiveness is.

Alkali aggregate has better adhesiveness with asphalt than acid agg, which means the better water stability of asphalt mixture is.

Evaluation method: Boiling water method for coarse agg; Immersion method for fine agg.

Technical Property of Petroleum Asphalt ——Adhesiveness ( 黏附性 )

2.2

Page 28: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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2.2 Technical Properties of Petroleum Asphalt

Page 29: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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薄膜烘箱薄膜烘箱 (Thin film oven test)(Thin film oven test)

旋转薄膜烘箱(Rotate thin film oven test)

压力老化箱压力老化箱(Pressure aging vessel)(Pressure aging vessel)

Influence factors on durability of asphalt: temperature oxidation ultraviolet ray water hardening Evaluation methods thin film oven test ( TFOT ) : for short-term aging rotation thin film oven test (RTFOT): for short-term aging, especially for modified asphalt pressure aging vessel (PAV): for long-term aging Evaluation indexes mass loss penetration ratio residual ductility

Technical Property of Petroleum Asphalt ——Durability ( 耐久性 )

2.2

Page 30: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Asphalt is a typical visco-elastic material, which means asphalt shows viscosity property under low temperature condition while shows elastic property under high temperature condition.

This kind special property can be expressed by the stiffness modulus. This modulus is related not only with stress and strain, but with temperature and loading time.

Stiffness of asphalt can be read from the nomograph.

Technical Property of Petroleum Asphalt ——Visco-elastic property ( 黏弹性 )

2.2

Page 31: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Technical Property of Petroleum Asphalt ——Visco-elastic property ( 黏弹性 )

2.2

Nomograph of asphalt stiffness modulus

Page 32: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Based on current specifications of our country, asphalt marks are divided by penetration, which means the greater penetration, the higher marks asphalt is.

To heavy traffic asphalt (GB/T15180—2000), the are 5 marks: AH-50, AH-70, AH-90, AH-110 and AH-130.

To road petroleum asphalt (JTG F40-2004), there are 7 marks, commonly used asphalt marks are: mark50, mark70, mark90, mark110 and mark130, etc.

Technical Specifications of Petroleum Asphalt

2.2

Page 33: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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Technical Specifications of Petroleum Asphalt

2.2

The smaller of penetration,

the lower mark asphalt is,

and the more consistency to asphalt,

which this mark of asphalt is more suitable to

the hot weather condition.

Page 34: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

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粘稠道路石油沥青(针入度分级 penetration grade )Chinese specification

Index LevelAsphalt

160# 130# 110# 90# 70# 50# 30#

Penetration degree @25 oC, , 5s (0.1mm)

140-200 120-140 100-120 80-100 60-80 40-60 20-40

Suitable climate subarea 2-1 2-2 3-2 1-1 1-2 1-3 2-2 2-3 1-3 1-4 2-2 2-3 2-4 1-4

Penetration Index A -1.5~+ 1.0B -1.8~+ 1.0

Softening point (R&B) ≥

A 38 40 43 45 44 46 45 49 55

B 36 39 42 43 42 44 43 46 53

C 35 37 41 42 43 45 50

Viscosity @ 60 oC (Pa.s)≥ A - 60 120 160 140 180 160 200 260

Ductility @ 10 oC (cm) ≥A 50 50 40 45 30 20 30 20 20 15 25 20 15 15 10

B 30 30 30 30 20 15 20 15 15 10 20 15 10 10 8

Ductility @ 15 oC (cm) ≥A、 B 100 80 50

C 80 80 60 50 40 30 20

Wax content (% ) ≥A 2.2B 3.0C 4.5

Flashing point (COC)(oC) ≥ 230 245 260 solubility ≥ 99.5 Density @15℃

After TFOT (or RTFOT)

Quality loss % ≤ 0.8

Penetration ratio after evaporation ≥

A 48 54 55 57 61 63 65

B 45 50 52 54 58 60 62

C 40 45 48 50 54 58 60

Ductility ratio after evaporation (10 oC) ≥A 12 12 10 8 6 4 -B 10 10 8 6 4 2 -

Ductility ratio after evaporation (15 oC) ≥ C 40 35 30 20 15 10 -

Technical Specifications of Petroleum Asphalt

2.2

Page 35: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

35

Technical Specifications of Petroleum Asphalt

2.2

Asphalt quality grades ( 沥青质量等级 )

All layers of third and under third grade highwayC

Lower layer of expressway and first grade highwayAll layers of second and under second grade highwayUsed for basis asphalt

B

All layers of all grade highwayA

Suitable forGrades

Page 36: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

36

——The brief Introduction of Stratagem Highway Researching Plan (SHRP) in America

美国战略公路研究计划 (SHRP) 是 1987 年由美国国会通过的一项为期 5年( 1988-1992 )的研究计划,其投资总额为 1.5 亿美元,目的是改善其国家道路的使用性能和耐久性,使得这些道路对使用者及其维护者都更加安全。该计划的资金来自联邦资助公路基金的 0.25 %的预留费。开发及评价道路施工、养护、管理创新技术的工作都以合同的形式委托给了大学、咨询机构和研究人员。研究成果分为四大部分:沥青、混凝土及结构、路面性能、公路管理等。

1991 年 ISTEA( 水路运输功效联合法案 ) 提供了 1.08 亿美元,由联邦公路管理局 (FHWA) 管理,主要是用 6 年的时间帮助各州及公路行业把SHRP 的成果推广应用并继续路面长期性能 (LTPP) 的研究。

如今,已开发的 SHRP 技术每年可以为美国节约大量的资金。联邦公路管理局已开发出一个有效的、创新的、灵活的实施计划,并承诺和公路行业的合作伙伴一起尽快地、有效地发挥这些效益 .

Technical Specifications of Petroleum Asphalt

2.2

Page 37: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

37

Asphalt properties are evaluated according to different three stages:

——during the transportation and storage stage;

——blending and spreading process; ——service stage of asphalt pavement.

All specifications are provided under same requirement rather than same temperature.

Put forward some new evaluate indexes and corresponding instruments.

Technical Specifications of Petroleum Asphalt

2.2

——characteristics of SHRP

Page 38: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

38

RV 试验( P48 )

Rotary viscosimeter (旋转式粘度计): measure viscosity of asphalt ( 用于测量沥青的 粘度 ).

——The brief Introduction of SHRP

Technical Specifications of Petroleum Asphalt

2.2

Page 39: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

39

——The brief Introduction of SHRPDSR 试验

Dynamic Shear Rheometer (动态剪切流变仪)( P58 ):Determination of viscoelastic properties of asphalt within temperature at 5-85 ℃before and after aging, and also presentation the ability for anti-rutting at high temperature condition ( 测定未老化和老化之后的沥青在 5-85℃温度范围内线粘弹性性质,并可用于反映沥青的高温抗车辙能力 ).

粘弹性

复数剪切模量 剪切应力

剪切应变

t

t 频率 相位角

Technical Specifications of Petroleum Asphalt

2.2

Page 40: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

40

DTT 试验( P51 )

Direct Tension Test (直接拉伸仪): Evaluation of asphalt material performances at low temperature, such as stress and strain when destruction, especially to evaluate the performances for polymer modified asphalt. ( 评价低温下沥青胶结料性质,如破坏时的应力和应变,特别适用于聚合物改性沥青,也用于评价沥青的低温性能 )

——The brief Introduction of SHRP

应力

应变

Technical Specifications of Petroleum Asphalt

2.2

Page 41: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

41

BBR 试验( P50 )

Bending Beam Rheometer (弯曲梁流变仪): Measurement

accurately of stiffness at low temperature and creep rate for asphalt ( 精确测量沥青的低温劲度模量和蠕变速率 , 用于评价沥青的低温性能 ).

——The brief Introduction of SHRP

蠕变荷载

位移

荷载 位移

时间 时间

Technical Specifications of Petroleum Asphalt

2.2

Page 42: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

42

Technical Specifications of SHRP2.2

Performance GradePG46 PG52

-34 -40 -46 -10 -16 -22

Average 7-day Maximum Pavement Design Temp(℃) <46 <52

Minimum Pavement Design Temp (℃) >-34 >-40 >-46 >-10 >-16 >-22

Original Binder

Flash Point (℃) >230

Viscosity , max , 3Pa.s,Test Temp (℃) 135

Dynamic Shear , G*/sinδ , min , 1.0kPa, Test Temp@10rad/s (℃) 46 52

RTFOT or TFOT

Mass loss, max, (%) 1

Dynamic Shear , G*/sinδ , min , 2.2kPa, Test Temp@10rad/s (℃) 46 52

PAV

PAV Aging Temp, (℃) 90 100

Dynamic Shear , G*/sinδ , min , 5000kPa, Test Temp @10rad/s (℃ ) 10 7 4 25 22 19

Creep stiffness , S , max , 300MPa,m-value,min,0.35

Test Temp @60s (℃)-24 -30 -36 0 -6 -12

Direct Tension Failure Strain,min,1.0%Test Temp @1.0mm/min (℃ ) -24 -30 -36 0 -6 -12

Page 43: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

43

Other Asphalt2.3

Page 44: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

44

http://wenku.baidu.com/view/738de20c844769eae009ed5a.html

aw bw bwW ;

;

;

,

aw

ab

bw

aw ab bw

ab aw bw

con

con

固气

固液

液气

是书中的

是书中的

是书中的

所以网络上的公式可表示成:

bwW (1+con )说明书中的式 2-26 符号也有误。所以将上式带入式 2-25 正确表达式,

,得到与书中相同的结果:

这张图是从网络上得到的截图(网址如上),表达了 young式方程。注意由于考虑的三相体与书中的不同,所以这里:

aw bw abW

Page 45: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

45

Polymer Modified AsphaltPolymer Modified Asphalt2.3.1

Page 46: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

46

Polymer Modified Asphalt ——Introduction

2.3.1

Purposes of modification

Improve high

temperature

stability

Improve high

temperature

stability

Resist cracking

under low

temperature

Resist cracking

under low

temperature

Enhance

anti-aging

capability

Enhance

anti-aging

capability

Improve

adhesiveness

between

asphalt and

aggregate

Improve

adhesiveness

between

asphalt and

aggregate

Page 47: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

47

SBS Rubber

Anti-rutting agent

fiber

Main types of modifications:1. Resin— 聚乙烯( PE )、乙烯 - 乙酸共聚物

( EVA ) ;2. Rubber— 丁苯橡胶( SBR )、废弃轮胎橡

胶粉 ;3. Thermoplastic elastomeric— 苯乙烯丁二烯

嵌段聚合物( SBS ) .

Polymer Modified Asphalt ——classifications

2.3.1

Page 48: 1 《 Road Engineering Materials 》 Chapter2 Asphalt materials

48

Segregation test (离析试验)—— to judge the consolute stability between modified agent and asphalt;

Elastic recovery test (弹性恢复试验)—— to evaluate automatic recovery capacity on deformation for asphalt modified with SBS after stretching;

Dynamometric ductility test( 测力延度试验 )——to detect the ability of modified asphalt resisting external tension.

Toughness and tenacity test (黏韧性试验)—— to be appropriate for asphalt modified with rubber,

Polymer Modified Asphalt ——Index Evaluation Methods

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Type of thermoplastic elastomer ( 热塑性橡胶类 )—— SBS( 苯乙烯丁二烯嵌段聚合物 );

Type of rubber (橡胶类)—— SBR( 丁苯橡胶 );

Type of thermoplastic resin (热塑性树脂类)—— PE( 聚乙烯 ), EVA( 乙烯 -乙酸乙烯共聚物 );

Type of thermosetting resin (热固性树脂类)—— EP( 环氧树脂 ).

Polymer Modified Asphalt ——Commonly Used modified asphalts

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SBS modified asphalt is most widely used on road pavement at present. Because this type modified asphalt can be benefit both to high and low temperature performances.

SBS is a polymer made of butadiene ( 丁二烯 ) and styrene ( 苯乙烯 ) in embedded way.

It is this special structure that makes SBS particular features.

Polymer Modified Asphalt ——SBS modified asphalt

2.3.1

SBS 原料

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单体丁二烯与苯乙烯以嵌段方式进行聚合,也就是说每一个 SBS 高聚物的中间部分是由丁二烯单体相连的 B段,而两端则是由苯乙烯单体相连的S段,所以称之为 SBS;

SBS既可以是线形结构,也可以若干个丁二烯链段在中间连接形成星型结构;

苯乙烯链段( S段)聚集在一起,形成物理交联区域,成为“硬段”(塑性段)。丁二烯链段( B段)聚集在一起形成“软段”(橡胶段) ,呈高弹态;

由于 SBS 高聚物两种不同链段的同时存在,使得 SBS具有两个玻璃化温度,分别是 80℃ 和 -80 ℃ ,分别是属于聚苯乙烯段和丁二烯段 .

Polymer Modified Asphalt ——SBS modified asphalt

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SBS 作为改性剂通过高温混合、溶解、溶胀等过程与沥青形成改性沥青。在通常使用状态下,由于温度低于苯乙烯的玻璃化温度,使沥青能够保持较高的抗变形能力,所以这种改性沥青赋予沥青混合料较好的高温稳定性;

而当处于冬季较低温度时,由于环境温度肯定会高于丁二烯的玻璃化温度,所以 SBS赋予沥青较好的低温柔韧变形能力,从而使沥青混合料又具备了较好的低温性能,这就是 SBS 改性沥青具有兼顾高低温性能要求的原因所在 .

Polymer Modified Asphalt ——SBS modified asphalt

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Compatibility is a key factor that affects modification effect. Benefits to compatibility include:

——The ratio of S/B, 30:70 is better than 40/60; ——Molecular weight is great, it has fine

modification result, but the processes becomes difficult;

——SBS with star style has better modification result than the line style, but also is difficult to process of preparation;

——The more aromatics in asphalt, the more benefit to compatibility.

Polymer Modified Asphalt ——SBS modified asphalt

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According to the type of Polymer, the modified asphalts are classified to three categories: (SBS), (SBR), (EVA and PE)Ⅰ Ⅱ Ⅲ ;

Each type of category is classified to A 、 B 、 C and D (except II) grade based on softening point. From A to D, penetration becomes smaller, viscosity becomes increase, which means performance on high temperature is improved while performance on low temperature becomes poor.

Besides ordinary evaluation indexes, some special indexes such

as segregation, elastic recovery, toughness and tenacity are offered to evaluate the performances of modified asphalt.

Polymer Modified Asphalt ——Technical Requirements for Modified Asphalt

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Indexes.SBS (I)(热塑性弹性体类) SBR (II)(橡胶类) EVA、 PE (III)(树脂类)

I-A I-B I-C I-D II-A II-B II-C III-A III-B III-C III-D

Penetration degree@25 oC, , 5s (0.1mm)

>100 80-100 60-80 30-60 >100 80-100 60-80 >80 60-80 40-60 30-40

Penetration Index ≥ -1.2 -0.8 -0.4 0 -1.0 -0.8 -0.6 -1.0 -0.8 -0.6 -0.4Ductility @ 5 oC, 5cm/min (cm) ≥ 50 40 30 20 60 50 40 -Softening point TR&B ( ) ≥℃ 45 50 55 60 45 48 50 48 52 56 60Viscosity@135 (Pas)℃ ≤ 3Flash point ( ) ≥℃ 230 230 230Solubility (%) ≥ 99 99 -Recovery of elasticity 25 (%) ≥℃ 55 60 65 75 - -Toughness and tenacity (N·m) ≥ - 5 -Toughness (N·m) ≥ - 2.5 -

Storage stability Segregation, difference of softening point after 48h ( ) ≤℃ 2.5 - 无改性剂明显析出、凝聚

TFOT(或 RTFOT)后残留物 Quality loss % 1.0 Penetration ratio after evaporation @ 25℃(%) ≤

50 55 60 65 50 55 60 50 55 58 60

Ductility @ (cm) ≥ 30 25 20 15 30 20 10 -

Polymer Modified Asphalt ——Technical requirements for modified asphalt

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Emulsified asphaltEmulsified asphalt2.3.2

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Asphalt heated in liquid state is scattered in mixture of water and emulsified agent by mechanical action to form emulsified asphalt.

Advantages of emulsified asphalt: ——It can be used under normal temperature so

as to save energy and reduce pollution; ——It can prolong seasonal construction, which is

rarely affected by low temperature and rain day. ——It has good adhesiveness and workability to

aggregates, so as to save asphalt and ensure construction quality.

Emulsified asphalt ——Introduction

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Asphalt: higher grade asphalt is suitable to emulsify.

Water: low hardness water is preferred. Emulsified agent: it is also known as surface

activity agent which plays very important role.

Stabilizing agent: it improves stability of emulsified asphalt.

Emulsified asphalt ——Composition

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Emulsified agent is one of the surface activity agents. This substance has special molecular structure which consists two parts: one is polarity on the end of molecular and one is no polarity on the another end of molecular;

Emulsified agent can be classified into:

Emulsified asphalt ——Emulsified Agent

2.3.2

Types of emulsified agents

Nonionic surfactant

( 非离子型 )

Ionic surfactant

( 离子型 )

Cation surfactant

( 阳离子型 )

Anionic surfactant

( 阴离子型 )

Zwitterionic surfactant

( 两性离子型 )

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Because any one molecular of emulsified agent has two different structure, this molecular can be absorbed on the surface of asphalt directionally, which nonionic part is towards to asphalt while ionic part is towards to water.

In this way, surface energy between asphalt and water is reduced remarkably. Asphalt can be scattered steady in the water to form emulsified asphalt.

Emulsified asphalt——Mechanism of Emulsification

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In order to bring into play asphalt cohesiveness, asphalt is surely released from emulsified solution, which is known as demulsification.

The causes to demulsify include:

—charge adsorption; —water evaporation;

—acid-base neutralization.

Emulsified asphalt——Mechanism of demulsification

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Retained mass after sieving; Residue after evaporation and properties; Viscosity; Adhesiveness; Stability in storage, and stability in storage

at low temperature; Feature on ionic electric charge; Speed of demulsification.

Emulsified asphalt——Evaluation Indexes for Emulsified Asphalt

2.3.2