Porous Sand-Asphalt Mixtures

7/24/2019 Porous Sand-Asphalt Mixtures

1/40

MEMO

TO:

FROM

SUBJECT:

March 22, 1974

Calvin G

Grayson

Assis tant

Sta te H i g h w a y , : ~ ~ ~ e r

Jas .

H

Havens

a,.,, f -

Direc to r o f R e s e a r c h ~

H-2-66

Proposed Spec i f i ca t ions

for

Sand-Asphalt

and

Open-Graded,

Plant -Mix Seal s .

At

a meeting

of the

Sta te Highway

Engineer s

s t a f f ,

November

2, 1973

(cf .

Research memo,

Nobember 13,

1973), Mate r i a l s ,

Spec i f ica t ions and Research

were

assigned the

development

o f

spec i f i ca t ions

to ca rry forward a de l ibe ra te ,

surfac ing

program

l ead ing

to the q u a l i f i c a t i o n of and s ~ d r d i z t i o n of sk id

r e s i s t a n t ,

pavement surfaces . The t a sk force mutual ly agreed

upon

a

plan

February

15,

1973.

This

submi t t a l includes

proposed

spec i f i ca t ions and

recommendations

toward

implementa t ion .

Two

spec ia l

provis ions are

proposed, as fo l lows:

1. ' 'Open-Graded

Fr ic t ion Courses

(P lan t Mix Seal s )

2.

' 'Sand-Asphalt

Surfaces ' '

The one

fo r

' 'Open-Graded Fr ic t ion

Courses' '

i s

e n t i r e ly new.

I t

admits

crushed,

s i l i ceous

grave l s and

crushed

s lag . Both

aggregates

(crushed,

quar tz

grave l and s lag)

were

put to

on-road t e s t l a t e

l a s t

year and are yie ld ing very

high

s k id - t e s t

r e s u l t s .

The

Sand-Asphalt spec i f i ca t ion

i s

very

encompassing and

may

be

used to

supp lan t S.P. 59-C,

S.P. 22-C and any others

which

have

not been

r e t i r e d . t

provides four types and(or)

grades o f

sands

and

commensurate

(presumably) l eve l s o f sk id

res i s t ance . t preserves the

use

of

common

sands

where high


2/40

Pag

e 2

emo M

arch

22

, 197

4

sk id

- res i

s t anc

e i s

not

r

equi r

ed .

Typ

es 1

and 2

are

p

a t ter

n ed

a f

t e r

S.

P . 2

2-C

a

nd

S.P.

59-C

.

They

a

re in tend

ed to

be

dense

,

s t a b l e ,

durable

su rface s ;

Ty pe

2

i s

s im ila r

to . th e

m ixture

plac

ed on

U

S

3

1-W,

fr

om

West

P

oin t

to Ky.

163

8

i

n 19

72

and 1

973.

T

ype 1 would

be

l

im ite

d

to

lo w - t

ra f f i

c s t

r e e ts

and

roa

ds. Type

2

i s

su i ta

b le fo r

he

avy

t r a f f

i c

whe

re

th

e

speed

l im

it is

60 m

ph

or

l e s s .

Typ

e

3

rep re

sents

an

a t

tempt

to

u t

i l i z e

u l t r

a - f in

e

s

ands

not

al

lowed

in

T

ype 4. Ty

pes

3 a

nd 4

are

ope

n-gra

ded.

The

grad

ation

s

f

o r Type

s 3

and

4 ar

e o b

ta ine

d ,

conc

eptua

l ly

s

peaki

ng,

b

y s p l i

t t in g

th e

grad a

tion fo

r T

ype 2

sand

a

t th e

N

o 30

s iev

e (co

u ld

be phys

ical l

y ac

com p

lished

in a

wet c

l a s s

i f i e r )

.

Th

e two f

ra c t io

n s d i

f f e r

in p

a r t i c

le s ize

on ly

; an

d

m ixt

ures

made

wit

h each

f r ac

t ion

shoul

d be s im

i lar i

n

terms

of

voids

and

p

a r t ic

le

shap

e. T

his h

as been

acco

m plis

hed in

the

la

b o ra t

o ry ;

how

ever,

we w

ere

una

ble

to

o b ta

in hig

h s

ta b i

l i t i e s

w ith

th e

crushed conglomerate

sands

in

th e

u l t r a - f i n e

s iz e s .

High

s t a

b i l i t

i e s we

re

achi

eved by b

lendi

ng

th e f in e

q u ar

tz

sands

w ith f in

e s

lag a

nd w

ith o t

he r f i

n e

sands

an

d

f i l l e

r s . S

umma

rily,

Ty

pe 3 would

req u

ire

abou

t

t

h e same

a

sp h a

l t

c

onte

n t as

Type 4.

W

e do

no

t

kno

w how

w

ell t

would

p

erfor

m

on

ro

ads a

nd s t r e

e t s .

S

econd

and

She

lby S t r e e

ts in

F

rank

for t (1966

) were

comp

osed

p

r in c i

p a l ly

o fv

ery f ine

sand .

The

so -ca

l l ed

' 'op

en-g

rading

' ' i s

ach ie

ved

by

shor t

ening

an

oth

erw is

e de

nse gra

dat io

n . T

he two

g

rada t

io ns in

Op

en-Gr

aded

F r i

c t ion

Cou

rses

. .

, to

ge the

r w it

h Typ

es

4 an

d 3 in

San

d

Asph

alt . . p

rovid

e a

spect

rum o

f

our s iz

e range

s .

We

need

to

kno

w th

e per

form a

nce

c h

a r a c t

e r i s t

i c s o f e

ach. Ho

wever

, w

e

are

recommending

only

Type

4

Sand-Asphalt

fo r

t r i a l s

on high

-spee

d ,

h e

a v y - t

r a f f i

c

roads

.

Fo

r th e f i r

s t

t im

e , we

hav

e

inc l

uded s

ta b i l

i t y re

quire

m ents

in

th e

sp e

ci f ic

a t io n

s . T

he p

urpos

e

i

s tw o

fold:

1) to p

rovid

e

a

ssu ra

nces

ag a

ins t

s c a l i

n g , a

nd 2)

to

a

ssure

th a

t

m at

er ia ls

supp l

ied have

th

ose

q u a l

i t i e s

w

hich

prod

uce s

ta b le

m

ixture

s.

In e

f fe c t

, t h i s

ty

pe of r

equire

ment

i s

an

ex t

ensio

n

o f

th e

so -c

a l led

job

-mix

formu

la

t

o mee

t

desig

n and

en

d-pro

duct

r

equir

ement

s fo r

the

mix t

ures.

T

he

d ra

f t sp e

ci f ic

a t io n

fo r

'

'Open

-Grad

ed, Fr ic

t ion

Cours

es

(

P lan t

Mix S ea ls )

was d is tr ib u te d

by

th e S p ec i f ica t ion s

s t a f f ,

Mar

ch

21

, 1

974.

In o

rder to

u n it i

z e th

i s

packa

ge, a co

py th

e reo f

and

th

e cove

r

me

moran

dum

i s

in

c lude

d herew

ith . T

his

i s th

e

f i r s t

at

tachm

ent.


3/40

P

age 3

Memo

M

arch

2

2, 1974

The

second

at ta

c hm ent i s

the propo

sed

s

pec i f i ca t i o

n fo r

sand a spha l t s .

The th i

rd attach

ment i s a shor t t r e a

t i s e

on

p r ~ s (open-gra

ded)

sand a sp

ha l t s ;

t was

prepared by

reques t fo

r

p re

sen ta tio n

a t

the H

RB m eeting

l a

s t

January

b

ut was not offe red

fo r pub l i -

cat io

n . I t s

more

s in g

ula r

purpose was

to

ac

company

t h i s submi t ta l

and to fu r t

h e r

exp la in

porous sand

asph alts and

th

e

spec i f

i ca t ions

now

propose

d.

The four th

attachm

ent i s a

l st of p r o j ec t

s no

w pending

o r

be

ing

co

ns idered

for resu rf

ac ing and

sugge

sted su

r face types

in

ter

ms

of

th

e

p

roposed s

pec i f i ca t io

ns .

JHH:gd

At

tachments

CC s: J

R H

arbison

C

alvin

Gr

ayson

J T.

Anderson

G F. Kem p

er

J

W S p

u rrier

J

D W i

tt

C

G ook

E.

B

aither

C

S.

Layson

J

E. McCh

ord

A

R Romine


4/40

MEMO

TO:

FROM:

DATE:

SUBJECT:

J T.

Anderson

c

G.

Grayson

G.

F

Kemper

J

w

Spur r ie r

J

D.

Witt

c.

G.

Cook

E

B. Gaither ,

J H.

Havens

C.

S. Layson

J r

~ ~ ~ ~ ~ : d ~ t ~

Jack F Miller

Assis tan t

to the S ate Highway Engineer

Specif ica t ions E t ff

March

21, 1974

Draf t

of Special Provis ion for

Open-Graded Fr ic t ion Courses

(Plant

Mix Seals)

In

compliance

with a

direct ive

issued at

the November

13,

1973

staff

meet ing, to

the Divisions of

Materia ls and

Resea rch

and the Specif ica

t ions

Staff,

the

subject draft has been

prepa red

and is being submit ted

for cons iderat ion and comments . This draft has

been

prepared so as

to

incorpora te the best

informat ion avai lable

f rom

other states and

F H. W.

A.

in

a context compatible

with K entucky s potential

aggregate sources

and

with

our present tes t ing procedures for

angular i ty.

Fur the r

input

f rom

each of your

offices

will be appreciated.

Draf ts of

separa te

specif icat ions for other sand-asphal t - type f r ict ion

cour ses

have also

been prepared

and will

be submit ted by Mr. Havens in

the near

future.

J FM : eq

Attachment

cc:

J R. Harbison


5/40

KEN

TUCKY

BUREAU OF HIG

HWAYS

SPECIAL P

ROVISION

NO

.

OPEN -

GRADED FR

ICTION COU

RSES

PLAN

T MIX SEAL

S)

This

Special

Provision

shall

be applicable

when

in dicated

in

the plans

or

proposal and sh

all

s

upersede

any con

flicting

requiremen

ts

of the

Burea

u s

1965

Sta

ndard

Spe

cifications for R

oad

and

Brid

ge

Constructi

on.

Section

a

nd Article

refere

nces

herein are to

th e Sta

ndard

Sp

ecifications

.

I DESCR

IPTION

T

his work

shall

consist

of const

ructing one co

urse of hot-m

ixed, hot

laid,

ope

n-graded surfa

ce

m

ixture upon

a sat

isfactory

fou

ndation of either

new o r exi

sting pa

vements. T h e

thicknes

s of the

cour

se shall

be nominally

3/4

inch thickness,

or

as

spe

cified on

the plans and

/or propos

al.

All

leveling,

wedging and

patching

deemed

necessary

by

the

Engineer to

repair an

existing

pave

ment shall

be

pe

rformed

before t

he construction

of

this

surf

ace course is

started.

This

open-g

raded m

ixture is in

tended

t

o pro

vide

a coarse

texture d

, well

dra

ining, skid

-resistant,

wea

ring

su

rface or vehi

cular traffic.

Special

att

ention shall

b

e given to all

aspects of

the work to

insure that only

top

quality mate

rials,

e

quipment an d work

manship are

utili

zed at aU

times a

nd

that t

he fi

nished surface

is in close

conform

ity

to th

e lines, g

rades

and

sections

indi

cated

in the plans ,and/

or propos

al.

II.

MATERIALS

A

ll m

aterials fo

r

use

in this

work must

be sample

d,

tested

an

d approved

prior to

starting the

production o f

the

o

pen-graded

mixtu

re.

Sin

ce

t

he angula

r aggregate r

equired for this

work

is

a

select

mate

rial,

the B

ureau,

upon

requ

est

y contracto

rs qualif

ied

to

bid on the

work, will

test a reaso

nable

numbe

r

of

source

sampl

es of aggregates

furnished

byth

e

contractors

, FOR INFORM

ATIONAL P

URPOSES ON

LY, prio

r to

the date of the

opening o

f

bi

ds or

the

contr

act.

Ho weve

r,

te

sts of

the

actu( l l

aggreg

ate

subsequen

tly stoc

kpiled at

the

p

lant site

y th e co

ntractor who

is

th

e succes

s

ful

bidder will

be made

to determine the

acceptability

of

the aggregate

or

the

wor

k.

T h e

c

ontractor or

th e

work shall

stockpile

aggregate at

the p

lant site or

sa m

pling

a

t

least tw o weeks

be fore sta

rting plant opera

tions.

Enough agg

regate

for one d

ay s plant

operation shap

be consid

ered th

e

m

n mum allowa

ble amount

of a

ggregate necessary

to

be

s

tockpiled

in order

th

at repres

entative

samples

for testing

may be taken t

herefrom.


6/40

Aggrega

te. Except for

mineral

filler, ag

gregate

for

this m

ixture

shall

be crushed

slag

, meeting

the qua

lity

r

equirements

of Spe

cial

Provisio

n No. 10

2, or crushe

d gr

avel meeting

the

requ

irements

of

Special

Provision No.

102

except

that:

1.

Pe

rcent C

rushed - The grav

el

s

hall

be a 100

crush

ed

produ

ct with at

least

95

hav

ing one

or

more

crushed

faces

and at least

75 ha

ving two or more c

rushed fac

es when

tested

by Kentucky

Method

64-603.

This

req uirement

is

considered

satisfied wh

en th egravel

is crushed

from ma

terial

of 3/4

inch

sieve

size or greate

r.

2.

Silica

Content

-

T

he

gravel shall

have a m n mum

silica

Si02) c

ontent

of 75 as de

termined by

Kentucky

Me

thod 64-224.

Crus

hed limestone shall n

ot

be

permitt

ed

in

th

is mixture. The

C

ontractor may requ

est a

pproval

for o

ther types

of agg

regate. Oth

er

aggrega

tes

sh

all

havea proven

re cord of satisf

actory

friction

propertie

s

acceptable to

the Depa

rtment and

sha

ll mee

t

the

quality requirem

ents

of

the

aggregates

listed

in

Special

Prov ision No.

1 2 for

general

uses.

Whe n

lightweigh

t

aggre

gates are

appro

ved, the applicatio

n ratea

nd

a

sphalt per

centage sha

ll

be

a

djusted

to

a

chieve

the app

roximate volume p

ercentages

used

in the slag

or crushed

g

ravel mixe

s.

The

gradati

on

of

th

e

agg

regate,

including

minera l

fil

ler when

used

,

shall

meet

either

the Type

1 or

Type

2 grading

wh

en

tested

by Kentu

cky

M

ethod 64-606

.

Prior

the start

of cons

truction, th

e C

ontractor

sha

ll

specify

in

w

riting to the

Engineer

w

hich gradi

ng (Type 1or

Ty p e

2

) he

elects to use. He sha

ll also

submit

aggregate

samples and a

job-

mix

form

ula

co

nsisting

ofa sing

le value for

perc

ent

pass

ing on each

sieve

.

Tolerances

from

the

approved

job-mix

formula

but

within

th emaster

grada

tion range sh

all ap

ply

to

a

ll mix

tures provided, as

indicated

in the

table

below.

SIEVE

SIZ E

1

/2

3/8

No. 4

No. 8

No.

16

No.

20

0

MASTER

GRADATION

RANGE

PERCENT

PASSING

Type

1 T

ype 2

100

90

-100

100

2

5-50 50

-100

3-15

10-30

-----

5-1 5

2-5

2-5

*Mast

er r

ange

app

lies

JOB-M

IX FORMUL

A

TOLERANCE

S

..6

..4

*

The

angularityof th e

aggregate

parti

cles shall

b

e

such th

at

the

aggregate

willhave

a voids c

ontent

of

49

or

more

whe

n

su

bjected

to

the

Dry-Bulking

Te

st in accordan

ce with Kentucky

Test

Met

hod 64-60

9.

Mineral

fil ler,

if

u

sed,

sha

ll conform

to

the quality

requi

rements of

Artic

le 611

5 . 0 .

Sheet

2 of 5


7/40

g j

The bituminous

material

for

the

tack coat may

be

SS-lh conforming

to SHO

M

140

except

the

maximum

penetration

may

be 100 RC-250

conforming

to

AASHO M 81

or other materials approved by the Engineer.

Q

Unless otherwise

specified

in the

plans

or

on the

proposal the

asphalt cement for the open-graded mixture shall be AC-20 conforming

to

the requirements of SHO

M 22 6.

When required by

the

Engineer

Silicone

shall be furnished by the

Contractor and blended

into

the

asphalt cement as directed by

the

Engineer. The

silicone

shall

be

of a type and from a source approved

by

the

Engineer.

L/

An

anti-stripping additive of

a

type and source approved by

the

Engineer

shall

be

furnished

by the Contractor and

shall

be used as

directed by the Engineer

when

necessary to

prevent

stripping

of the

asphalt

from

the aggregate.

III.

CONSTRUCTION METHODS

Every requirement contained in Articles 3 06.3 .1 through 3 06.3 .1 0 that is

applicable to this type of work shall be

in force

except

as

provided herein and

in

the

plans

and

on

the

proposal.

The materials

equipment

and methods for leveling wedging and patching

shall

be those

designated

in the

proposal. The leveling

and wedging

shall

be

constructed

as

specified

in Article

3

06.3.

8

and shall be constructed

to

within

plus or

minus

1/4 inch of the desired elevation

as

determined by a stringline

measurement or by

a template. The contractor shall furnish

any

templates

in

accordance with

Article

3

06. 3. 2.

The

leveling

wedging

and

patching operations

are

particularly

significant to

the satisfactory performance of this type of surface

mixture and every reasonable effort shall

be

made to provide a uniform stable

and closed even

surface

as

a

foundation

for this

open-graded course.

f paved shoulders are

used or

i f

there

are

curb and

gutter

sections on

the

project

the open-graded mix should be

higher

than the shoulder or the gutter to

provide the

proper

drainage of the mix.

fi Tack

Coat.

When SS-lh is furnished for

the tack coat

it

shall be

diluted with

an

equal

amount

of water conforming to section 603

and thoroughly

mixed

prior

to

application.

The

diluted

SS-lh

shall

be

applied

at

an approximate

rate

of 0. 2 gallon

per

square

yard

in

one

or more applications and with a

sufficient

amount of time and

distance

allowed in advance of the paver to insure

that all of the water has escaped

and

evaporated before any of the mixture is

laid on the tacked

surface.

When

RC-250 is furnished for the tack

coat it

shall be applied at an approximate

rate

of 0.

1

gallon per square yard and with

a

sufficient time and distance allowance in advance of the paver to insure that

the volatiles

have evaporated

before

any of the

mixture

is laid

on the tacked

surface.

The open-graded mixture shall not be laid

on

the tacked surface

until

authorized by the

Engineer.

Sheet

3

of

5


8/40

When

other materials are approved by the Engineer they shall be

applied as directed by the Engineer.

Seasonal and

Weather Limitations.

The

mixture

shall be placed

only when

the

pavement

surface

is clean and dry

and

when

the

pavement

surface

temperature is 50F

or

greater. The air

temperature

shall

be

at

least

50F

and

rising.

No

seasonal limitations shall apply.

l

Preparation of Open-Graded Mixture. The mixture shall be prepared

by combining

the

approved

aggregate

with asphalt cement

in the

percentages

established by

the

Engineer. The percentage by weight of

asphalt cement

in

the

mixture will be established between 5. 5 and 8. 5 percent of the

total

mixture. The gradation limits for

the

mixture are

the

same as those

specified for

the aggregate and the

Engineer

will

approve a

job-mix formula

within the

specified

aggregate

gradation

and asphalt

content

limits.

Deviations from the

established asphalt

content

shall not

exceed 0. 4

per

cent when

the

mixture is tested by

Kentucky

Method 64-405.

1. f the aggregate for the mixture is a blend of two or

more materials

the materials shall

be

supplied from

individual cold bins

or stockpiles

in

the proportions required to meet the gradation and voids content specified

herein.

2.

The

temperatures of the materials and the mixture

in degrees

Fahrenheit shall be

maintained

within

the following ranges:

Aggregate

Asphalt Cement

Mixture

at

Plant

Mixture when Laying

MINIMUM

200

250

200

180

MAXIMUM

26

300

260

260

Q

Paving.

Insofar

as practical

the

paver shall

be

operated at a

constant forward

speed that will

produce

a smooth uniform

mat

free from

tears open areas and other imperfections. Any raking done should

be

kept to the absolute minimum.

Rolling. Normal

equipment

for

placing and compaction will apply

except that

rolling

shall be accomplished

by

means of

a

8-10

ton

steel

wheel tandem roller. The amount of rolling shall

be

confined to

only

that

necessary

for

consolidating the bituminous

mixture and bonding

it

to the underlying surface. Excessive rolling shall be avoided.

Sheet 4 of 5


9/40

IV

M E T H O D O

MEASUR

EMENT

The

open grad

ed mixture

will bemeasure

d intons

in acco

rdance with

A

rticle 1 9

. 1.

T he

bi

tuminous materi

al for tack co

at will

be meas

ured

in

g

allons in accordance

w

ith Sect

ion

62

1.

V BA

SIS OF PAYM

ENT

The accepted

quantities

of open gr

aded mixtur

e an

d

bi

tuminous ma

terial

for

tack coat wi

ll

b

e paid

for

in accor

dance with

Article

3

06. 5. 0 excep

t that

an

y

silicone

or

anti

strippin

g

add

itive fo r the

mixture an

d any

wat

er used fo r

dilut

ing the S

S lh willbe c

onsidered

as incident

als and

will

not be pa

id

fo

r

sepa

rately.

ppro

ved

J R. HARBI

SON

STATE HIG

HWAY EN

GINEER

Sheet5

of

5


10/40

SAND ASPHALT SURFACES

This

Spec ia l Provis ion

sha l l

be

appl icable

when

indica ted in

the plans

or

proposa l and

s ha l l

supersede

any

co n f l i c t i n g

requirements

of

the Department s

1965 Standard Spec i f ica t ions

fo r Road

and Bridge Cons t ruc t ion .

Sect ion

and A r t i c l e

r e f e r

ences

here in a re to the Standard Spec i f i ca t ions .

I .

DESCRIPTION

This

work

s ha l l cons is t o f the cons t ruc t ion o f

one

course

of

hot-mixed, h o t - l a i d Sand-Asphalt Surface mixture

upon

a

sa t i s f a c t o ry

foundat ion

of

e i the r

new of ex i s t ing

pavements.

The th ickness

of the

course sha l l be approximately

3/4 inch.

Al l

l eve l ing

wedging and

patch ing deemed

necessary

by

the

Engineer to r e p a i r an ex i s t i n g pavement

so

t wi l l provide

a

smooth,

uniform

and sa t i s f a c t o ry foundat ion sha l l be

performed

before cons t ruc t ion

o f

t h i s

sur face course i s

s t a r t e d .

These sand-aspha l t mixtures are in tended to

provide

f i n e -

tex tu red s k id - r e s i s t a n t

wearing

sur faces

for vehicula r

t r a f f i c .

Specia l a t t en t ion s ha l l be given to a l l aspec t s o f the work

to

insure t ha t

only h igh qua l i ty mate r ia l s equipment, and

workmanship

are

u t i l i z e d

a t

a l l

t imes

and

t ha t

the

f in i shed

surface

i s in

conformi ty to the l i ne s grades

and

sec t ions

ind ica t ed

in the plans and /or

proposal . These

sand-aspha l t

mix-

t u r e s

are des ignated as

fo l lows:

Type

l dense-graded,

fo r general use

Type

2 dense-graded,

skid r e s i s t an t ;

for

moderate-speed

t r a f f i c


11/40

SAND

ASPH

ALT SUR

F CES

Th

is Sp

ecia l

P rov

is ion

sh a

l l b

e

appl i

cable

when

in d ica ted

in

th e

pla

ns or

p

rop o s

a l and

s h a l

l

s

upers

ede a

ny

c o n f

l ic t in

g

requi

remen

ts o

f th

e De

partm

ent s

1965

St

andar

d

S p e

c i f ic

a t io n

s

fo

r

Roa

d and

Bridg

e C

onst

ruc tio

n .

Sec ti

on

an

d

A rt ic

le r e

f e r

e

nces h

erein

ar

e

to

t

h e S

tanda

rd S p

ec if i

ca t io

ns .

I

.

DES

CRIPT

ION

This

work

s

ha l l

co n

s is t

o f

the

co n

s t ruc

t ion

o f o

ne c

ourse

o f

ho

t-m ix

ed, h o

t - l a i

d Sa

nd-A

sphalt

Surf

ace

m ix

ture upon

a


founda tion

o f

e i th e r

new o f e x is t ing

pavements.

T

he t

h ick n

ess o

f

the cour

se

s h a

l l be a

pprox

im ate

ly 3/4

in c

h .

A l

l

le v e

l ing

we

dging

and

pa

tching

de

emed

n

ecess

ary

by

the

Eng

ineer to

re p

a ir an

e x i s ti

n g

pavem

ent so

t

w il

l provi

de

a

smoo

th,

unif

orm and

sa t i s

fa c t o

ry f

ound

ation

sh a l

l be

per

forme

d

befo

re

co

ns t ru

c t ion

o f

th i s

su r

face c

ourse

i s

s ta r

te d .

These

s

an d -a

sp h a

lt mixt

ures

are

in te

nded

to p

rovid

e

f i

n e -

t

ex tu r

ed

s k id

- r e s i

s ta n t

w

earin

g su rfa

ces fo r

veh i

cula r

t r

a f f i c

.

Spec

ial a t ten

t io n

s

ha l l be

giv

en

to

a

l l a

sp ec t

s o f th e

wor

k

to

insu

re

th a t

only

h

igh q u

a l i ty

m a

te r ia l

s

eq

uipme

nt, and

work

mansh

ip

are u t

i l i z e

d a t a

l l

tim

es

an

d

th a

t th e f in

i shed

su rfa

ce i s i

n

confo

rm ity

to

the l in

e s

gra

des and

sec t io

n s

in d

ica te

d

in t

h e p

lans

and

/or p

ropos

al.

T

hese

s

an d -a

sp h a

lt

m

ix-

tu re s

are

de

s igna

ted

as

fo llow s:

Type

l

den

se-g

raded

, fo r

gener

a l u s

e

Ty

pe

2

den

se-g r

aded

,

sk id

r e s

i s t a n

t ;

fo r

m o

derat

e-spee

d

t r a f

f i c


12/40

SANDASPH

ALT SURF C

ES

This

S pec ia l Provis ion

sh a l l

be

app l icable

when

indica ted

in

the p l

ans

or

p ro po

sal and

s ha l l supersed

e any

conf l i c t in

g

re

quiremen t

s

of the Depar tm

ent s

1965 Stand

ard

S p ec i f

ica t ion s

fo r

Road and

Bridge

Co n stru

ct ion . Sect i

on and A

rt ic le re f

e r

ences here in

ar

e

to

th e Sta

ndard S p e

cif ica t ion

s .

I

DESCRIPTIO

N

T

his

wo

rk sha l l

co ns is t of the

cons t ru

c t ion o

f one co

urse

o f

hot-mixed

, h o t - l a i d

Sand-Asph

alt

Surfac

e mixture

upo

n

a


foundat ion

of

e i th e r

n w

of

ex i s t ing

pavements.

The

th ickn

ess of

the course sh a

l l be a

pproximate

ly 3/4

inch.

All

le

v e l i n g we

dging and

pa

tching deemed nec

essary

b

y

the

Engineer

to

re p a i r an

e x is

t i n g pave

ment so

t w i l l

pro

vide

a

smooth,

unif

orm

and

s a t i s fac to

ry foundat

ion sh a

l l be p

erformed

be

fore

cons

truc t ion o

f th

is sur face cour

se i s

s ta r te d

.

These

sa

nd-aspha l

t

m i

xtures

are

in t

ended

to provide

f ine -

tex

tu red

s k i d - r e s i

s t a n t wear ing

sur fac

es fo r vehicula

r t r a

f f i c .

S

pecial a t t en t

i o n s h a l

l

be

given

to

a l l asp

ec ts o f th e

work

to in

sure

t ha t only

high

q

ua l i ty m

ate r ia l s

equipmen

t, and

w

orkmanship

are

u t

i l i z e d a t

a l l t imes

and

t ha t th e f in i shed

s

ur face i s in

conform

ity

to

the

l

in e s g

rades, and sec t

ions

in d ic

a t ed

in

the plans

and or pro

posal . These sa

nd-aspha l

t mix-

tu re

s are

desig

nated as

fo

l lows:

Type

1

de

nse-grad ed

, fo r

gen

eral use

Type 2 dense-g

raded,

sk id

r e s i s ta

n t ; fo r

m o

derate-spe

ed

t r a f f i c


13/40

-2 -

Type 3

open-graded;

sk id r e s i s t a n t ; in tended

fo r

moderate t r a f f i c .

Type 4 open-graded;

skid r e s i s t an t ;

in tended

fo r

high speed

heavy t r a f f i c .

The type o r types sha l l be des ignated on

the

plans

o r

proposals .

I I . MATERIALS

All mater ia l s for

use in t h i s work

must be

sampled

t e s t e d ,

and approved p r i o r to s t a r t i n g the p roduct ion o f the sand-aspha l t

mixture.

The

Contrac to r fo r

the work

sh a l l

s tockp i l e

sand a t

the

p lan t

s i t e

fo r sampling a t l e a s t 2 weeks before s t a r t i ng

p lan t

opera t ions .

A s u f f i c i e n t quant i ty o f

sand

to supply

one

d ay s p lan t

opera t ion sha l l

be

cons idered al lowable s tockp i l e t o obta in

t e s t

samples.

A. The

bituminous mate r i a l

fo r

the

t ack coa t

sha l l conform to

the requirements

in

the plans and proposal .

B. The aspha l t cement fo r

the

sand-aspha l t mixture sha l l conform

to

the requirements in

the

plans and

proposal .

C. Since the angular sand r eq u i r ed

fo r

t h i s work i s a se l e c t

mate r i a l ,

the

Bureau upon

reques t

by Contrac to rs qua l i f i ed

to

bid

on

the

work

wi l l

t e s t

a

reasonab le

number

o f

source

samples

o f sand

furnished

by the Cont rac to rs ,

fo r in fo rmat iona l purposes

only , p r i o r to the date o f the opening o f bids for the con t rac t .

However

t e s t s

of the ac tua l sand

subsequent ly

s tockp i led a t

the plan t

s i t e

by

the Contractor

who i s the success fu l b idder

wi l l

be made

to

determine the accep t ab i l i t y o f the sand

fo r

the work. The sand fo r the sand-a spha l t mixture sha l l

be obta ined


14/40

-3 -

from n a t u ra l

p

rocessed

o r c

rushed mate r i a l s

in wh

atever

combin

ations th

a t may be p ra c

t i ca l . The

sand m

ay

c o

ns is t

of

e i the r q uar tz

sand, na tu ra

l sand s l ag

sand

, ceramic

sand, o r

com binat ions

th e reof .

The

combined

carbonates

expressed as

ca l

c ium

ca

rbonate

equiva len

t; Ky . T es

t M

ethod No f

o r sands

used

in Type l

m ixtur

es

s

h a l l not

exceed

p e rcen t

;

car

bonates

in Type

2 sand

s h a l l not

excee

d

25 p

ercent ; carb o

nates in

T

ype

3

and Type

san

ds s h a l l

n ot

exceed 15 p

ercen t

The

m ximum q u

an ti ty o f m in

eral

f i l l e

r

which

may be

incorpo

ra ted

in

to

the sand in

o r

der

fo r t

h e

sand

to

conform

to

the

sp ec if i ed

gradati

on

i

s 5 pe

rcen t fo r Type I a

nd 2

and

1

5 p ercen t

f

o r

Types

3 and

Each in

g redient sa

nd used,

except

mineral

f i l l e r

s

h a l l have a

Sand

-Equivalen

t

valu

e of

not

le

s s than

10;

th e

b lend

includ

ing

m in

eral

f i l l e r sh a l l

have

a

Sand-Eq

uivalent va lue

o f

not

le

s s tha

n 25.

Dele t

er ious s

ubstances re ta in

ed

on

t

he No.

200

s ieve sha l l no

t exceed th

e follow

ing percent g

es by

weig

ht

o f

th

e t o t a l

combi

ned

san

d mixture

:

Clay lumps

Other

de l i t e r io u

s

sub

stance

su

ch a s but not l i

mi t ed

to

a l k a l i

mica,

sha le

coat

ed

g ra i n s

so f

t

and

f

laky p a r

t i c le s

Percent by

Weigh

t

None

1.

0

The angu la r i t

y o f the

sand

p a r t ic le

s

fo r

use in

Type 2, 3 ,

o r

mixtures

sh a l l

be

such

t h a t

th e

sand

w il l

have

a

voids

con tent

o f

percen

t

o r

more when

su b jec

ted

to

the Dry-B

ulking T es

t in

accor

dande with

Kentucky Tes t

Met

hod 6 ~ 6 0 9 .


15/40

-4-

D

Mineral

f i l

l e r i f

used

sh a l l

c

onform to the

quali ty r

equ ire

ments of Article

611. 5. 0

and s

hal.l not be fly

ash.

E

Silicone

sh al l

be

of

a

type

and

source

approved

by

the

Enginee

r and sh

a ll be fur

nished an

d used as

directed

by

the

Engineer.

F.

A hea t -stab

le an t i -st r

ipp ing

a

ddit ive of a

typ

e and source

approved

by the E

ngineer shal l

be

furnishe

d w

hen necess

ary

by the

Contracto

r an

d

shal l

be used

as dire

cted by the

Enginee

r.

I I I . CONS

TRUCTION

METHOD

S

E

very

r

equirement

con

tained in Ar t ic

les 306.3

.1 througJ

.

306.3.

10 tha t

i s appl i

cable

to

th

is

type of w

ork

shal l

be in

forc

e except

as provid

ed herei

n and in the

plans an

d proposal.

The

m ate

rials equipment

and

methods

for leve

l ing we

dging

and pa

tching sh a

ll be t

hose designate

d in

t

he pr

oposal.

The

le

vel ing an

d wedgi

ng

sh

al l

be

co

nstructed

as

specif i

ed

in

A r

ticle 30

6.3.8 and

sha

ll be constru

cted

to within

plus or

minus

1/4 in

ch

of

the

d

esired

elev

ation as determ

ined by

a

s t r ing l ine

m

easuremen t

or by

a templ

ate. he

Contrac

tor

shal l

f

urnish any te

mplates in acco

rdance

with Art ic

le 30

6.3.2. The

level in

g wedging

and

patching

o

perations

are p art ic

ular ly

s ignif ica

n t to the sa t i sfa

c tory

performa

nce of th is

type of

surface

mixture

and

every

reasonable

e f fo r t

sha ll

be

made

to

provide a unifo

rm

stab

le

and even

surface a

s

a

foundatio

n

for

th is sand-asph

alt

course.


16/40

-5 -

A. T

ack Coat. W

hen SS-lh

i s fur

n ished fo r the ta

ck c o a t

t

s h a l

l be d i lu ted

w

ith an equal a

mount

o f water conformi

ng to

Sect ion

6

03

a

nd tho

roughly

mixed pr i o r

to app l ica t i

o n . Th

e

d i

lu ted

SS-lh

s h a

l l

be

appl ie

d a t a

n approxima

te r a te

of

0

.1 g a l . /

s

q yd

.

fo

r Type 1

and2

m

ixes

and 0.2 g a l .

/ s q .

yd.

in

two o r

more a pp l i

ca t ions fo r

Type

3 an

d 4 m ixes. S u

f f ic ien t

time s h a l

l

be a

l lowed t

o in s

u re

t ha t

a l l the

water has eva

porated b

efore

the

m ix

ture

i s

place

d on t he tacked

surface . The

sand -asph

al t

m ixture

s ha l l

no t

be

l a i d

on

the

tacked

su rfac e

u n t i l

au thor ized

by

the Engine

er. When RC-25

0

i s furn ish

ed for the tack

coa t

t

s h

a l l be

app lied

a t an appr

oximate

r a t e o f 0

.1 ga l . / s q . y

d.

a

nd a s u

f f i c i en t tim

e

and

dis tance

in

adv

ance o

f

th e

paver

to

insure

t

h a t the

v o la t

i l es

have

evapor

ated be

fore

any of th e m i

xture

i s la id

on

th

e

t

acked

su rfa

ce .

B

Seasonal and Weathe

r L i m i

ta t ions .

The sand-a s

p h a l t m

ixtures

s ha l l be

la i d

only a t

t imes when

a l l w ea

ther co ndi t ion

s ar

e

ve

ry favorab

le in the

judgment

of

th

e Engineer whe

n th e

atm

ospheric

tem

perature

i s above

60

F . and

when th

e underly in

g pavem

ent

i s

c lean

and dry

exc

ept

for

th

e ta ck

coa t .

C

Prepa

ra t ion

o f

the San

d-Asphalt

Mixtur

e.

T

he sand

and a s p h a

l t

c

ement s h a l

l be

combined

in

th

e p ropo

r t ion s es ta b l is

hed

by th e

E ngineer

. A job-m

ix o r m u l ~

dete

rmined by the

Marsha

ll

Design

Metho

d wi th i

n the spe ci f ied

g rada t io

n

and

as

phal t conte

n t

l i m i

ts

w i

l l be e

s ta b l i shed

by t

he Engin

eer fo r each

pro j e ct .


17/40

-6 -

Deviat ions

from

the

es t ab l i shed a spha l t content

sha l l not

exceed

0.5 pe rcen t and the f ine ss modulus o f

the sand sh a l l

not

vary

more

than

0.2

from

the

value

es t ab l i shed

by

the

job-mix

formula.

The grada t ion o f

the mixture

by dry

s ieving

sh a l l be

as fo l lows:

PERCENT PASSING

SIEVE SIZE

1/4 inch

No 4

No.

8

No.

16

No.

30

No.

50

No. 100

No.

200

Type

1 o r

100

75-100

60-95

45-90

20-65

3-20

2-6

2

Type

3

100

40-65

25-36

5-15

Type

4

100

40-65

10-40

5-15

1. I f the sand fo r the mixture i s a blend o f

two

o r more

mate r i a l s the mate r i a l s sha l l

be

supp l ied from i nd iv idua l

co ld

bins

in

t he propor t ions es t ab l i shed

by

the

Engineer .

2. The t empera tu res

o f

the mate r ia l s and the

mixtures

sh a l l

be maintained with in

the

fo l lowing ranges :

Sand

265-3750f

Asphil.l

t

Cement

275-3500f

Mixture

a t

Plant

265-350F

Mixture

when

Placed

250-350F

Marshal l

Design

Method c r i t e r i a are as fo l lows:

Minimum

Air

Mixture

S t a b i l i t y Clb

Voids

( )

Type 1 300

3-9

Type

2

600

3-9

Type

3

400

9-18

Type 4 1000 9-18


18/40

-7 -

D In s o

fa r a

s p ra

c t i c a

l th

e pav

er s

h a l l b

e o

pera t

ed a t

a

c

ons ta

n t forw

ard spee

d

t h a t w

il l

prod

uce

a smoo

th unif

orm

mat

f ree

from

t e

a r s op

en a rea s

and

o th e r

im

p er f

ec t io

n s .

E A

ll in

t e rs e

c t io n

s appr

o ache

s

en tra

n ces

a

prons

ma

ilbox

tu rn

o u t s

and

o t

h er in c i

d e n ta

l

a

reas

t

h a t

a

re to be

su

r faced

as

a

p a

r t o

f

th e

wor

k s h a l

l b

e

surfac

ed e i

th e r

befor

e o r a f

t e r

the

layin

g

o

f th e

s

and-

aspha

lt su

r face

cou

rse

on

the main

l ine

so

as n

ot to

d e t

ra c t

from

nor

in t e r

f e r e

with

th

e p

aver

o p

era t i

ons

in

any manner

while

t h i s

course

i s

being

ap p lied

to

th e

t r a f f i c

la n

e s .

F

Ta

ndem

r o l

l e r s w

eighi

ng n o

t le ss

than

5 nor mo

re

than

8 to ns

s h

a l l be u

sed

fo

r th

e com

pacti

on o f

t

he sa n

d -asp

hal t

mix

tu re

and

the

su r

fac in

g

o f

the

i

n c id e

n ta l

a

re a s .

G

Ve h i

cular

t r a f f

i c s h

a l l

no t

be

perm

itted

to

u

se

th

e

com

pacted

sand

-asph

alt mix

ture u

n t i l

thas

co

oled

s u f f

i c i e n

t ly to

w ith

s tand

the t r a f

f ic w

ithou

tany

d

amage

In t

e r s e c

t io n s

and any

o th

e r

a re

as

w

hich

mu

st be

reop

ened t

o t r

a f f i c

soon

a

f t e r th

e sand

asp

ha l t m i

xture

ha

s

been

com

pacte

d s h

a l l

be

thoro

ughly

spray

ed

with

wa te

r so

as to

h a

s ten

th e

co o l

ing

o f

th e com

pacted

m

ixtur

e

to a

tmosp

heric

t

em pe

ra ture

b e

fo re

t

i s su b j

ec ted

to t r

a f f i c

.

An

y ad j

acen t

a r

eas to

re

ce iv e

th e

sa

nd-a s

pha l

t

co u

rse w

hich

a re

w

et ted

by

th e

water

s h a l l

be a

llowe

d to

tho r

ou hl

y dr

y befo

re

th

e san

d-a sp

ha l t co

urse i s

l a i d

.

IV

MET

HOD

OFME

SUREM

ENT

The

san

d-asp

ha l t mix

ture w

il l

be measu

red

in

ton

s

in

acco

rdanc

e

w

ith

A r

t ic le

1 .9 .1

.

The bitu

m ino

us m

ate r

ia l

for

t ack co

a t w i l l

be mea

sured

in

g a

llo n s

in

accor

dance

w

ith Se

c t ion

621


19/40

8

V BASIS

OF P YMENT

The

accepted q u an t i t i e s of sand aspha l t

mixture

and

bituminous

mater ia l for t ack

coat

wi l l

be paid

fo r i n accordance

with A r t i c l e

306.5 .0

except t h a t

any ~ i l i c o n e and/or a n t i s t r i p p i n g add i t ive

fo r the mixture and

the water

fo r d i lu t ing the

SS lh

and

fo r

coo l ing

the

pavement

wi l l be cons idered as i nc iden ta l s and wi l l

not be paid

for

sepa ra t e ly .


20/40

Research R

epor t

385

POROUS SAND

-ASPHALT M IX

TURES

y

as H

Havens Direct

or

o

f Research

BURE A

U OF HIGHWA

YS

K e

n t ucky Depar t me

nt o f Transpor t

at ion

prepared f

or

Session 47 Spon

sored by Com m

ittee A2DOS

Program

on

Skid-Resistan ce - C or re ctive Measures using

Bitum

inous Surfaces

5

rd Annual Meeti

ng Highway Re

search Board

Sherato

n-Park Hotel

Washingt o

n D. C

January 24 197

4


21/40


22/40


23/40

sea

l co

ns tr

ucte

d in

197

3 o

n a

n ab

ut ti

ng s

ectio

n o

f th

e sam

e

road

.

N

ow,

it is

ap p

aren

t th

at th

e sh

ape

and

te xt

ure q

ua li

ties

soug

ht in

sand

s fo

r san

das

ph al

ts are

con

vers

e

to t

hose

sou

ght

for

po r

tland

ce

men t

co

ncre

te an

d m

ort a

r sa

nds. Riv

er

sa

nds,

glac

ial

sand

s, es

peci

ally

glac

ial

ou tw

ash

san

ds,

and

bea

ch a

nd

blow

san

ds t

en d

to

be r

ou nd

ed ,

fros

ted,

an d

pol

ished

. M

any

sand

ston

es

an

d con g

lom e

rate

s yi

eld s

harp

a

ngula

rsan

ds.

Crus

hed

ma

nufa

cture

d no

nuca

rbon

ate

san

ds

al to

ge th

er

o

r

b

lend

ed w

ith

qual

ifyin

g n

atura

l sa

nd f

racti

on s

may

pro

vide

new

op

por t

uniti

es t

o

ut

ilize

lo

cal

reso

urce

s

andin

digen

ous

ma t

erial

to

achi

eve

skid-

resis

tant

pave

men

t su

rface

s. C

ontr

olled

wea

r

and

at

tritio

n

arees

sent

ial. h

e

surf

ace

the

refor

e b

ecom

es

sacr

ificia

l bu

t re

newa

ble.

S

cali

ng

S

calin

g, i

llust

rated

in Fig

. I

is

a

ttrib

uted

to

a de

ficie

ncy

in

the

desig

n of

th

e m

ixtur

e . th

at is

in

stab

ility

. Us

ual ly

, su

ch

mixt

ures

are

de fi

cien

t in

asph

alt

and

or )

fille

r. F

ailure

s ar

e ac

com

pani

ed b

y

str i

ppin

g of

asp

halt

from

the

san

d p

artic

les.

Coat

ings

are

thin

, an

d as

ph al

t me

nisci

are

not

well

form

ed

atthe

int

er-pa

rticl

e co

nta c

ts. P

ersis

ting

wate

r or

con

tin u

al w

etnes

s i

n co n

jun c

tion

with

load

ing

acce

lerat

es

sc

aling

8)

. Ha

rd

asph

alts

impr

ove

stab

ility

, mi

nim i

ze s

pon

gines

s, a

nd are

m

ore

resi

stant

to

strip

ping

.

A

ntis

tripp

ing

age

nts

may

be

need

ed

with

som

e a

ggreg

ates

. Ke

ntuc

ky

Roc

k As

phal

t su

rface

s sh

owin

g

go o

d d

urab

le p

erfor

man

ce c

on ta

ined

asp

halt

bind

ers

{afte

r

1

5

yea

rs or

so

in se

rvice

) ha

ving

pe n

etrat

ions

of

ab o

ut 1

5. N

o sa

nda

spha

lt or

Roc

k A

spha

lt ha

ving

stab

iliti

es M

arsh

all) o

f as

mu

ch as

40

0 ha

s sc

aled.

F

ig. I

Earl

y S

calin

g of

S

an da

sp h

alt h

avin

g L

ow

St ab

ility

and

In

suffi

cien

t

Asp

halt.


24/40


25/40

App

ro xim a

te ly 1

50 0 gr

ams o

f each

ofthe

above

sizes

shall

be requ

ire d f

or the

tests.

T

he tes

t shall

be co

nd ucte

d on o

nly th

e speci

fied

size frac

tions h

aving

5 perce

nt or

more

of the

aggreg

ate by

weigh

t co n

tained

in the

give

n specif

ied siz

e fract

ion.

A size

ofthe

aggreg

ate

shall be

po ured

into t

he fun

ne l wh

ile a s

ti ff pie

ceof

me tal is

held

aga inst

the

ottom o

pening

. The

funnel

shall

be flll

ed un t

il the

materi

al is h

eaped

be twee

n 1 a

nd 2 in

ches

above

its to p

level;

care s

hall be

take n

not to

overf

low th

e funn

el or t

o spill

ma teri

al into

th e cy

lin der

b

elow.

The pi

ece o

f metal

used t

o close

the b

otto m

openin

g of

the fun

nel sha

ll

be

q

uickly

withdr

aw n

in a ho

rizont

al mov

em ent

and th

e mate

ria l pe

rm itte

d to fl

ow free

ly into

the cylinder until it overflow s.

Th en,

the flo

w of t

he ma t

eri al on

to the

filled

cy linde

r shall

be cut

off, a

nd any

ofthe

materi

al rema

ining

in the

funne

l shall

be al

low ed

to flow

into

a pa n

.

Th

e mat

er ial in

the

cylinde

r shall

then

be care

fu lly s

tru ck

offeve

n with

the to

p of t

he cy l

inder

with

the st

rai ghte

dg e. Th

is is a

cco mpl

ish ed b

y hold

ing the

straig

hte dg e

in bo t

h han d

s, edge

do wn;

sta rting

at

one sid

e, strik

e off

the ma

terial

above

the to p

of th

e cylin

der. Th

e strai

ghtedg

e is the

n plac

ed alon

g

a dia

meter

of the

cy linde

r and t

he ma t

erial st

ru ck of

f again

. This

is then

repeate

d in th

e opp o

sited ir

ec tion.

Ex t

reme c

are sh

all be

ta ken

during

the st

rik ing-

of f op e

ra tion

to avo

id any

down w

ard p

ressure

on th

e

agg

regate

or any

jarrin

g of t

he cy l

inder.

After

caref

ull y re

mo ving

any

materia

l that

may

be ad h

eri ng t

o the

ou tsid

e of th

e cylin

de r, th

e

weig

ht of

the co

nt ents

shall

be dete

rm ined

to th

e near

est

0.1 gram

.

The

aggrega

te in t

he cy l

ind er s

hall th

en

be recom b

ined w

ith th

e exces

s of th

e sam

e siz

e

f

rom th

e

pan,

th oro u

gh ly m

ixed,

and tw

o ad d

itional

de term

in atio

ns mad

e. An

avera

ge of th

ree de

te rmin

at ions

havin

g a m

aximu m

varia

tio n

of 4 gr

ams sh

all co

ns titute

a tes

t.

T

he pe r

ce nt v

oids in

each

size sh

all

be de term

in ed

by th e

follow

ing fo

rm ula:

wh e

re

Perc

en t vo

ids

10 0 1 -

- )

VG

W =

averag

e weig

ht of

materi

al in t

he cy l

in der,

V = v

olume

ofcy l

inder i

n cubi

c cent

im eters

, and

G bu l

ksp

eci fic g

ravity

oven

dr y) o

f the ag

gregat

e as de

termin

ed y

the app

licable

portio

ns

of

ASTM C

127.

The

ar ithm

etical a

verage

ofthe

perce

nt void

s so d

eterm i

ne d fo

r the t

es ted

size .. t

ha t is

the su

m

of th

e perc

en tage

s divid

ed by

the n

um ber

ofsiz

es test

ed s

hall be

repor

ted.

Fig.

2 sh

ows

the te

st be

ing p

erform

ed.

Fi

g. 2:

Bu

lking

Test;

for

Contro

l

of

Aggre

gate

Shape

.

5


26/40

Figs. 3 through 6 illustrate, by association, the relationship between the bulking value and particle

shape

II).

The test

is

subject to some error when the aggregate

is

highly vesicular. The errors arise

from inherent inability to determine the true, oven-dry, bulk, specific gravity.

The bulk specific gravity

of slag

larger than the No. 4 sieve may be about 2.30; fine slag sand

passing the No. 30 or No. 50 sieve may exceed 3.00. Expanded shale fines may range 2.59 and 2.84.

Quartz grains approach 2.64.

ll

approach zero percent absorption

as

the size diminishes. The specific

gravity

of

powdered material

is

equivalent to that of a voidless mass.

Porosity and Capillarity

A relatively dense sand-3sphajt gradation divided at the No. 30 sieve will provide a coarse and fine

sand, each of which will yield about twice the VM

in

asphalt mixtures

as

the original sand. The coarser

fraction would not contain filler; the filler would have to

be

added. Such sorting might be accomplished

in

a wet classifier. ll filler could be removed and proportioned back into each of the sands at the

hot-mix plant. The two mixtures would be very much alike

in

terms

of

total voids porosity) but have

very different pore sizes. Capillary rise and wicking would be greater in the finer mixture if the voids

remain open

and

if the internal surfaces

are

wettable. Both the coarse

and

fine mixture would exhibit

wicking capabilities. Wicking

is

merely capillary forces at work in a porous medium.

Capillary rise, capillary siphoning, and wicking are illustrated

in

Fig. 7. Height H must be sufficient

to overcome the tensions holding the drop at the tip of the tube before efflux will occur. A wick

may substitute for or extend a capillary tube,

as

shown.

Suppose the capillary rise

is

I em. in a surface course which

is

2 ems. thick; if the surface course

were inundated by rain surface flow and some internal flow would carry the excess water to a lower

elevation; the free-water surface would then subside into the surface course; ordinary gravity drainage

would cease at some point; shallow basins would siphon by capillary action) into lower basins and

emerge laterally or surface at low points; water which can form concave surfaces menisci) having shorter

radii than the pores causing capillary rise will not drain, the hydrostatic law does not apply; as drying

progresses the menisci recede but blotting c ;tpacity remains

high;

additional water cast onto the surface

is absorbed readily.

Clogging of Pores

Soil and road scum intrusions affects the porosity and surface texture of various types of bituminous

surfaces. Dust tends to adhere to

fresh asphalt until the asphalt becomes de-tackified; interior surfaces

also retain dust; this mineralizing process improves wettability with respect to water and gives

rise

to

capillary action. Permanent clogging may occur, but the pumping action induced by passing tires during

rainy periods tends to flush and clear pores in the wheel paths.

Fig. 8, left, illustrates a dense, sand-asphalt surface, outside the wheel paths, which is clogged and

not readily wettable. The righthand view shows the same drop of water after the addition of a wetting


27/40

>--

'

>--

'

'

j

:0

D

-

a

0

__

6

'

>--

z

w

u

a

w

-

E X ~ N E SHALE

CRUSHED

KENLITE

Fig. 3:

CRUSHED SANDSTONE

CONGLOMERATE

JENKINS

UNCRUSHED SAND FRACTION

OF CONGLOMERATE

{ aseyville )

GREEN RIVER

UNCRUSHED RIVER

SAND

OHIO RIVER

(

Carrollton

)

4-8 SIEV

AVERAG

UNCRU

OH

(P

Bulking Value

of

Sands Associated Visually with Particle Shape; No. 4


28/40

ti

w

U

0

-

i

z

2

-

j

z

::> w

aJ u

'

w

i a_

65

EXFI\NDED

SHALE

CR

USHED

KENLITE

8-16SIE V

E

AVERAGE

CRUS

HED SANDSTO

NE

UNCRUSH

ED SAND FRACTION

UNCRUSHED RIVER

UNCRUSH

CONGLOMERA

TE

OF CONGLOMER

ATE

SAND

SA

(Coseyville

I

JENKIN

S

GREEN RIVER

OHIO RIV

ER

OHIO

I Carrol

lton I

Pad

Fig. 4:

Bulking

Va lue

of

Sands

Ass ociated Visu

ally with Particle

Sh a pe; No. 8

to

No. 6

Sieve S

izes


29/40

f

'

f

'

f

z

.J

w

::J

u

'

'

w

>-

-

'

"'

I

EXF \NDED SHALE

CRUSHED

KENLITE

Fig. 5:

""'

CRUSHED

SANDSTONE

CONGLOMERATE

JENKINS

UNCRUSHED

SAND FRACTION

UNCRUSHED RIVER

OF CONGLOMERATE SAND

Caseyville)

GREEN RIVER

OHIO RIVER

Carrollton )

Bulking Value

o

Sands Associated Visually with Particle Shape; No. 16

t

No 30 Sieve Sizes

16-3

AVE

UN


30/40

-

z

w

0

:

w

o_

EXR


31/40

C PILL RY RIS

T

I

1

Fig. 7:

Fig. 8:

0

0..

O SIPHON

0

ROP OR STRE M . . 0

lllustration of Capillary Rise, Capillary Siphoning and Wicking.

Quarter-Inch Diameter

ead o

Water left) on Dense, Clogged

Sand-Asphalt Surface not readily Wetted; Wetting Agent Induces Wetting

right) without Blotting.

I I


32/40

agent. T

he surfa

ce wette

d, but t

here w

s no in-

rush or

blotting.

In con

trast, Fig

. 9 show

s a dry

ing

porous

sand-asp

halt Ke

ntucky

Rock A

sphalt) w

hich ha

s been f

ully wet

ted and

flushed

clean in

the

w

heel pat

hs. Blot

ting occ

urs read

ily. Traf

fic assis

ts the w

etting p

rocess i

f the sur

face

is

s

omewha

t

hydro

phobic a

t first a

nd also

hastens

the de-s

aturation

process

.

T

ack Co

at

Porous s

and-asph

alts have

a high b

lotting c

apacity

toward a

sphalt us

ed in the

tack coa

t. An abu

ndant

ta c

k applic

ation see

ms nece

ssary

t prevent

delamin

ations a

nd t se

al the u

nderlying

pavem

ent. t

is

us

ually p ru

dent

t subtract

an equiv

alent am

ount of

asphalt

from des

ign aspha

lt conte

nt of the

mixture

.

This a

djustme

nt becom

es very

significa

nt when

the san

d surfac

e course

is

very

thin.

Particl

e Orient

ation an

d Surfac

e Textu

re

Pa rti

cles havi

ng one

or more

flat sid

es tend

to be p

ositione d

in the

surface

during c

ompactio

n

so that th

ey prese

nt a flat

side rat

her than

an acute

angle or

cutting

edge tow

ard the t

ire. In th

is positio

n,

the edges,

if

th ey remain sharp contribute to tractive resistance. The micro-texture

of

th e flat surface

may b

e lost th

rough w

ear and

polishing

. Certain

ly, micro

-texture

is

obscu

red by as

phalt wh

en the s

urface

cours

e

is

new

. Skid-r

esistance

should

improve

rapidly

for a b r

ief time

and the

n dimini

sh gradu

ally to

a more-o

r-less c

onstant v

alue. A

ttrition o

r loss o

f partic le

s from

an open-

graded, p

lantmix

seal wou

ld

present

an impr

ession o

f ravelling

; attritio

n from

a sand su

rface wo

uld be d

esirable

if it occu

rs unifor

mly

and at

a rate c

ommens

urate wi

th the li

fe expec

tancy o

f surface

course.

Indeed,

a steady

wearing

away

b

ecomes

an assur

ance aga

inst even

tual pol

ishing o

f sand g

rains at

the surf

ace. Fine

r sands

appear t

o

be more

favorab

le from

this po i

nt of

view than

coarse s

ands. A d

mittance

of finer

sands a

lso perm

its

a hig

her size-

reduction

ratio an

d conseq

uently p

rovides g

reater an

gularity

when ma

nufactur

ing sharp

sands

b

y crushi

ng coars

e sands o

r pea gra

vel.

No4 t No.

8 siz

e

do

not app

ear to be

essential

to the p

erforman

ce

of san d

mixture

s.

O ri

entation

of partic

les of f

ine, crus

hed qua

rtz sand

, oiled a

nd comp

ressed l

ightly ag

ainst a f

lat

surface

, is show

n in

F

ig. 10.

2


33/40

Fig. 9:

Fig

. 10:

Porous SandAs

phalt Kentucky

Rock Asphalt,

after Rain; Sho

wing

C

leansing of

Wheel Paths; Surface

Blots readily.

Particle Or

ientation

o

Co m

pressed Fine San

d; Flat Sides Te

nd to be

Horizontal.

3


34/40

Fig. 9:

Fig. 10:

Porous San

d-Asphalt Kent

ucky Rock Asp

halt, after Rain;

Showing

Cleans

ing o

Wheel

Pa

ths; Surface Blo

ts readily.

Particl

e Orientation

o Compressed Fin

e Sand; Flat Sid

es Tend to be

Horizontal

3


35/40

SUMMARY

Skid Resistance

Thus far, dense sand-asphalts containing blends o crushed limestone sands and natural sands have

performed bout equiv lent

to bituminous concretes cont ining

n tur l s nds

nd

crushed

limestone

co rse

aggregates. All-limestone sand-asphalts have performed about the same

as

all-limestone bituminous

concretes. Sand-asphalts containing all-natural sands have tended to exhibit higher skid resistance;

variability in shape texture nd composition has affected performance; a crushed quartz sand in a dense

sand-asphalt is showing very good skid resistance after a year under severe traffic. A porous sand-asphalt

containing selected quartz sand less angular than crushed sand has shown superiority over the same sands

in denser mixtures. The ultimate combination o high porosity and sharp angular crushed quartz) sands

or other hard vesicular sands such

as

slags scoria or expanded shales have not been field tested.

Performance equations indicating statistical confidence limits with respect to time

nd

accumulated traffic

are yet to developed. Performance equations are needed to qualify types o surfaces and materials to

meet minimum standards or criteria for skid resistance.

Porous sand-asphalts may be considered to possess almost all of the attributes o a popcorn mix

or n open-graded plantmix seal. They do not have comparable pore sizes. For instance unless a porous

sand-asphalt surface is pre-wetted before making and

ASTM

E 274

skid

test, the water sprayed in front

o the test wheel has not significant time to wet

or

be blotted into the surface. The effect on the

Skid Number might be about the same

as

i the test were made on a dense, non-wetting surface. On

the other hand, a fully-wetted, but unsaturated porous sand-asphalt may imbibe the sprayed water

very

quickly.

Other Attributes

Sand-asphalt surfaces and more especially the more porous ones generate a minimum o tire noise

and tend to damp other noises generated by a vehicle. Under-car noise caused by splash and spray in

wet weather

is

reduced. More significantly, perhaps, the spray generated by vehicles

is

reduced unless

water is ponded or the surface is otherwise flooded.

14


36/40

RE

FE

RE

NC

ES

I

Go

ld b

ec

k, A

T.

; "

S to

ne

S

an d

f

or U

se

a

s

Fi n

e

Ag

gr e

ga t

e;"

C

onc

re

te ,

Vo

l.

5 9

; 1

95

1.

2

.

C

ar te

r,

Ja

s.

L.,

Jr

:

11

A

St

udy

o

f t

he Serv ice Life

of

Pave m ents

in

K entucky;'' Thesis,

M

S

in

C

E.;

U

niv

er s

ity

of

K

en

tu c

ky

, 1

95

5.

3

.

C

ra n

e,

C.

W

;

"S

an d

f

or

Sh

ee t

A

sp h

al

t P

av e

me

nts

;

P

ro c

ee

di n

gs ,

F

if th

A

nn

ua l

A

sp

ha l

t P

avi

ng

C o

nfe

re n

ce

; T

he

A

sp h

al t

A

sso

ci a

tio

n;

19

26 .

4.

N

ic h

ol

so n

, V

ic

to r

; "

A

Stu

dy

of

th

e

E ff

ect

of

S

ha p

e o

f

Mi

ner

al

Ag

gre

ga t

e o

n

Sta

bil

it y

of

A

sp h

al t

Pa

vin

g M

ix

tu r

es ;

" P

ro

ce e

di n

gs

, F

if th

A

nn

ual

A

sp h

alt

P

avi

ng

Co

nfe

re n

ce

; T

he

As

ph

al t

As

so

ci a

tion

;

19

26

.

5.

Ga

ge ,

R

. B

.;

Di

scu

ss i

on

of

R

ep

or t

b

y C

W

C

ra n

e;

Pro

ce

ed i

ng s

, F

if

th

An

nu a

l

Asp

ha

lt

Pav

ing

Co

nf

er e

nce

; T

he

A

sp

ha l

t P

avi

ng

A

ss o

ci a

tion

,

192

6.

6

.

N

ijb

oer

, L

W ;

Pl

as t

ic it

y a

s

a F

ac

tor

in

th

e

De

sign

of

D

en

se

Bi

tu m

in

ous

R

oa d

C

ar

pet

s; E

ls

ev ie

r,

1

94

8.

7.

Hav

en

s,

Ja s

. H

.;

11

H

ot-M

ix

S

an d

S

urf

ac e

;"

Pr o

ce

ed i

ng s

, K

en

tu c

ky

H

igh

wa y

C

on

fe r

en c

e;

Bu

llet

in

90

,

Co

lleg

e o

f

En

gin

ee

rin g

,

Un

iv e

rs it

y o

f

K e

ntu

ck

y;

O c

to b

er

19

69

.

8.

M

aj

id z

ad e

h,

K.

, a

nd

S

ta n

der

, R

.

R.,

Jr

.;

"E f

fe c

t o

f

W a

ter

on

B

eha

vio

r o

f

San

d-

As

pha

lt

M i

xt u

re s

und

er

R

epe

ate

d

Lo

ad i

ng ;

H

ig h

wa

y

Res

ea

rc h

R

eco

rd

N

o. 2

73

;

HR

B;

19

69

.

9.

Fa

ro u

ki,

O

m a

r T

., a

nd

W

in t

er k

orn

, H

an

s F

.;

"M

ec h

an

ic a

l P

ro p

er t

ie s

of

G

ra n

ula

r S

yst

em

s; "

H

igh

wa

y

Re

se

ar c

h R

ec

or

d N

o.

5

2;

HR

B;

19

64

.

1

0 .

A r

m s

tr o

ng

, Ja

m

es

C.,

an

d

D u

nla

p,

Wa

yn

e A

.;

"T

h eU

se

of

P

ar t

ic u

la t

e M

ec

ha n

ics

in

th

e S

im

ula

tio

n

o

f

St

re s

s-S

trai

n

Ch

ara

cte

ri s

tic

s o

f

G

ra n

ula

r

M

ate

rial

s;

' R

es

ea r

ch

R

ep

ort

N

o.

9

9- 1

,

Te

xa s

T r

an

spo

rt a

ti o

n

Ins

ti tu

te ;

A

ug

ust

, 1

96

6.

1

1.

Ha

ve

ns ,

Ja

s.

H .;

11

Ag

gre

ga t

e S

ha

pe

an

d

Sk

id

Res

is t

an c

e; "

C

on

fe r

enc

e P

ro

ce e

di n

gs ,

C

onf

er e

nc

e o

n

S

ki

d R

es

is ta

n t

Su

rfa

ce

C

ou r

se s

; C

hic

ag

o

Hei

gh

ts ,

il l.

; S

ep

te m

be

r

14 -

16 ,

1

971

;

Reg

io

n 1

5,

U

S

Dept.

of

Transp ortati on .

1

5


37/40

LIS

T

OF PRO

JE CT

S

AND

S

UGG

ESTE

D

SUR

FAC

E TY

PES

Pad

uca

h

Be

lt l i

n e

MP 73

-633

2-G

; E

.

cur

b li

ne o

f

Ky

994

to

W

. c

urb

l ine

o f

Brid

ge S

t . ; U

.

S.

6

8, 62

, 6

0;

2.0

0 m

i.

Rec

omm

end

ed S

urf

ace

:

Op

en-

Gra

ded F

r ic

t ion

Cou

rse,

Ty

pe 1

o r

Type

2;

o r

Sand-Asphalt

Surface

Type

2

o r

T

yp e

4

.

P

adu

cah

-Bro

okp

ort

L a

ndi

ng,

MP 73

-601

2-N

; N.

cur

b lin

e o f

Je f

fe rs

on

S

t.

to

WC

L

(

300

E

. o

f

J e

t .

U

.

S. 4

5 a

nd N

.

8t

h

S t .

; U .S

.

45;

1

.7 m

i.

Re

com

men

ded

Surf

ace

:

O

pen-

Gra

ded F

r ic

t io

n

Co

urse

, Typ

e 1

or

T

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Porous Sand-Asphalt Mixtures

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