2
Model Specification for Pavement Layers made from Soil Stabilised by Lime and Hydraulic Binders BRITISH LIME ASSOCIATION 1. General This model specification describes the requirements for the constituents, composition and performance of sub-base and base layers made from soil stabilised with combinations of lime, ground granulated blast furnace slag, pulverised fuel ash, cement and hydraulic road binder. The specification relates primarily to mix-in-place treatment but can be adapted for central plant mixing. 2. Standards Lime - BS EN 459-1: 2001 Cement - BS12 Ground granulated blast furnace slag - BS6699: 1992. Fly ash - BS 3892 part 1: EN450 Hydraulic road binders - DD ENV 13282: 2000 Methods of test for stabilised soils - BS1924: 1990 3. Definitions, symbols and abbreviations PFA - pulverised fuel ash also known as (coal) fly ash. GGBS - ground granulated blast-furnace slag. HRB - hydraulic road binder (a factory blended hydraulic binder specifically for roads and pavements) HB - hydraulic binder (a material that hardens both under water and in air, when mixed with water) e.g. cement, HRB, and the lime/PFA or lime/GGBS combination. SHB - soil treated or stabilised by an hydraulic binder OMC - optimum moisture content MCV - moisture condition value 4. Constituents 4.1 Soil Soil for SHB shall be naturally occurring material, artificial material, recycled material, or a combination of these. When wet sieved, not less than 95% of the soil shall pass the 63mm sieve. Organic matter, if present, shall not adversely affect the performance of the mixture. If this exceeds 2% by weight, laboratory tests shall be carried out to confirm that the required strength can be achieved. Soil, particularly that containing or suspected of containing sulfates or other potentially disruptive material, shall be deemed suitable for treatment provided the requirements of clause 8.13 are satisfied both at laboratory mixture design stage and during construction. 4.2 Lime Lime shall be quicklime to EN459-1: 2001 and the following specification: CaO + MgO content > 80% MgO content < 10% Reactivity with water, established in accordance with EN459-2, shall achieve a temperature of at least 60 degrees C within 25 minutes. (Less reactive Quicklimes may be used providing complete hydration is ensured before final compaction.) Particle size: For in-situ treatments 100% passing a 10mm sieve and at least 95% passing a 5mm sieve or finer. Where airborne dust is less critical, such as a sealed static mixing plant, finer grades of quicklime may be used. Where a sealed mixing plant is to be used and dust is not a concern Hydrated Lime to BS EN 459-1: 2001, CL90 may be considered. The drying reaction achieved with Quicklime will not be present using Hydrated Lime. 4.3 GGBS GGBS shall comply with BS6699: 1992. 4.4 PFA PFA shall comply with BS 3892 part 1 or EN450. The Engineer may also approve dry or conditioned (wet) run-of-station ash providing recent supplier certificates indicating the physical and chemical characteristics of the material are available. Before use, conditioned PFA shall be stored for at least 3 days at minimum moisture content of 10% and screened to remove particles greater than 10mm. 4.5 HRB HRB shall comply with DD ENV 13282: 2000. 4.6 Cement Cement shall be portland cement complying with BS EN 197-1: 2000. 4.7 Water Water shall not contain components that affect the performance of the SHB. 5. Composition 5.1 SHB shall be made from constituents selected from section 4 using proportions that satisfy the requirements of this section and the performance requirements of section 8, particularly noting the requirements of sections 8.10, 8.11 and 8.12 on strength, trafficking and frost resistance respectively. 5.2 Unless otherwise agreed by the Engineer, the minimum proportions of a constituent in any mix, by dry weight of the total mix, shall be; lime 1.5%, GGBS 3%, PFA 5% (8% in the case of conditioned PFA), HRB 3% and cement 3%. 6. Method Statement 6.1 Before commencement of the main works, the contractor shall provide a full method statement. This shall specify the operational procedure for the works, site preparation, type of plant and programme. Specific details shall be supplied regarding estimated durations and intervals between the main stages of the treatment, lime amelioration stages (if applicable) and the hydraulic binder addition, curing and protection. 6.2 In particular, the method statement should specify the procedures, controls and production checks with respect to site preparation, powder spreading, pulverisation (if applicable), water addition, MCV, depth of mixing, compaction, insitu density measurement, level control, finishing rolling, curing and protection. 6.3 The method statement shall include the intended mixture proportions, the supportive data to justify the proportions, the moisture content and related MCV limits and binder additions for all stages of the work. 6.4 The method statement shall include a sample record sheet to be completed for each construction bay detailing; construction times, sample and test locations and check results for all control parameters including those in clause 6.2. 6.5 The main works shall not commence until receipt of a satisfactory method statement and record sheet. 7. Demonstration area 7.1 Prior to the commencement of the main works, the contractor shall undertake a demonstration area of at least 800m 2 conforming to his method statement. The demonstration area shall consist of at least 2 full-width bays so as to include a transverse end-of-bay joint. 7.2 The demonstration area may be accepted into the permanent works with the agreement of the Engineer. 8. Mixture Performance and Construction Requirements The frequency of tests, controls and checks shall be in accordance with 8.14. 8.1 Spread rates With the exception of conditioned PFA, which shall be spread by blade, dry powders shall be spread by purpose-made spreaders at rates high enough to avoid non-uniformity and low enough to minimise displacement by plant that traverse the area just spread. This will normally be between the ranges 8 – 20 kg/m 2 . 8.2 Amelioration Where lime is used to ameliorate (break down) cohesive soils prior to the addition of GGBS, PFA, HRB or cement, it shall be added and mixed with the soil not less than 24 hours nor more than 72 hours before the subsequent addition. For sulfate bearing cohesive soils this period shall be between 48 and 72 hours. During this period it must be ensured that any quicklime added to the soil is fully hydrated. The moisture content at this stage shall be not less than the OMC (or more than the equivalent MCV) for the lime modified mixture determined in accordance with the 2.5kg Proctor method of BS1924. 8.3 Mixing and pulverisation Mixing and pulverisation shall be carried out by one or more passes of a purpose made mixer until uniformity is achieved. In the case of amelioration of cohesive soils (8.2), the degree of pulverisation of the full depth of treatment after lime addition shall be in excess of 30%, or other agreed value, determined in accordance with BS1924. For cohesive mixtures after final mixing of the final constituent addition, the degree of pulverisation of the full depth of layer shall be in excess of 60% or other agreed value. NOTE: The measurement of the degree of pulverisation may be difficult with mixtures at or wetter than the OMC. 8.4 Depth of mixing. The depth of mixing at all relevant stages of the process shall be checked using suitable reference stations to ensure that after final trim and compaction, the final thickness of the layer is to specification. 8.5 Final water content At final compaction, the moisture content for granular mixtures shall be not less than 0.9 OMC determined in accordance with the vibrating hammer method of BS1924, and for cohesive mixtures not less than the OMC (or more than the equivalent MCV) determined in accordance with the 2.5 kg Proctor method of BS1924. 8.6 Compaction Final compaction, including finishing rolling, shall be completed within 2 hours of mixing of cement, 4 hours for GGBS and HRB, and 6 hours for PFA.Where a single powder is added over 2 operations, the time shall apply from the mixing of the first application. 8.7 Surface finish On completion of final compaction, the surface of the layer shall be well closed, free from movement under compaction plant, and free from ridges, cracks, loose material, segregated areas, pot holes, ruts and other defects. On no account is it permissible to add thin layers of material to build up areas that are low once rolling has started. 8.8 Density The full depth of the layer shall be compacted to an average density of not less than 95% of the average fresh wet density of the strength specimens made in accordance with clause 8.10. The insitu wet density shall be measured using a nuclear density gauge in accordance with BS1924: 1990. The average insitu densities shall relate to the mean of the results for one day production samples specified in Table SHB. 8.9 Sealing Immediately on completion of compaction, the surface of the layer shall be sealed with a bitumen emulsion applied at the rate of 0.5 litre/m 2 . Alternatively another approved product at an equivalent application may be used or a single surface dressing (see 8.11) to achieve a continuous and consistent seal across the whole area of the works. 8.10 Strength Strength shall be measured using samples of the mixture representing the full depth of the layer after final mixing. Groups of cubic or 1:1 cylindrical specimens representing one day’s work shall determine the average compressive strength. They shall be made in rigid plastic (HDPE) moulds and compacted to refusal within one hour of the final constituent addition in accordance with either BS1924 or using MCV apparatus. The specimens shall be sealed and cured as described in BS1924-2, section 4.1.6, using the recommendations for cement to cover SHB that contain cement and the recommendations for lime to cover SHB that do not contain cement. The strengths recorded shall be not less than 1 MPa or other specified value (see 8.11 and 8.12). NOTE 1: Whatever the age of testing and curing conditions, it should be noted that SHB made from high plasticity clays may struggle to reach compressive strengths of 1 MPa. NOTE 2: As an alternative to, or in conjunction with, compressive strength, laboratory or insitu surface stiffness can be specified. For guidance, in comparison with the above compressive strength, laboratory NAT stiffness would range upwards from 1000 MPa and, depending on age and temperature, insitu surface stiffness from 200 MPa. MCV apparatus has been found suitable for the manufacture of NAT stiffness specimens. NOTE 3: As a further alternative to compressive strength, soaked CBR testing may be employed. Typically, a CBR value of 100% may be considered equivalent to 1 MPa compressive strength. 8.11 Trafficability Unless agreed otherwise, construction plant and traffic shall not run on the layer other than to enable construction of the overlying layer. Note: Experience suggests that SHB meeting the strength level of 1 MPa specified in 8.10 should provide a sufficiently robust layer for site trafficking associated with the next layer and possibly for drainage and edge detail work. Where trafficking will be light, a specified strength as low as 0.5 MPa may suffice. Where heavy trafficking is expected then a specified strength of at least 1.5 MPa will be necessary. In the later case, consideration should be given to the application of a surface dressing. lime think 21425_specPav1_sheet 13/1/06 12:12 pm Page 1

Model Specification for Pavement Layers made 8. … Specification for Pavement Layers made ... furnace slag,pulverised fuel ash,cement and hydraulic road binder. ... fresh wet density

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Page 1: Model Specification for Pavement Layers made 8. … Specification for Pavement Layers made ... furnace slag,pulverised fuel ash,cement and hydraulic road binder. ... fresh wet density

Mod

el

Spec

ific

atio

n fo

r Pa

vem

ent

Laye

rs

mad

efr

om S

oil

Stab

ilise

d by

Lim

e an

d H

ydra

ulic

Bin

ders

BR

ITIS

H L

IME

AS

SO

CIA

TIO

N

1.G

ener

al

This

m

ode

l sp

ecif

icat

ion

de

scri

bes

the

req

uir

emen

ts

for

the

con

stit

uen

ts,

com

posi

tion

an

d pe

rfor

man

ce

of

sub-

base

and

base

laye

rs m

ade

from

soi

l sta

bilis

ed w

ith

com

bina

tion

s of

lim

e,gr

ound

gra

nula

ted

blas

tfu

rnac

e sl

ag,p

ulve

rise

d fu

el a

sh,c

emen

t an

dhy

drau

lic

road

bi

nde

r.Th

e sp

ecif

icat

ion

rela

tes

prim

arily

to

mix

-in-

plac

e tr

eatm

ent

but

can

be a

dapt

ed f

or c

entr

al p

lant

mix

ing.

2.St

anda

rds

Lim

e -

BS E

N 4

59-1

:200

1C

emen

t -

BS12

G

roun

d gr

anul

ated

blas

t fu

rnac

e sl

ag -

BS

6699

:199

2.Fl

y as

h -

BS 3

892

part

1:E

N45

0H

ydra

ulic

roa

dbi

nder

s -

DD

EN

V 1

3282

:200

0 M

etho

ds o

f te

st f

orst

abili

sed

soils

-

BS19

24:1

990

3.D

efin

itio

ns,s

ymbo

ls a

nd a

bbre

viat

ions

PFA

-pu

lver

ised

fue

l ash

als

o kn

own

as

(coa

l) f

ly a

sh.

GG

BS -

grou

nd g

ranu

late

d bl

ast-

furn

ace

slag

.H

RB

-hy

drau

lic r

oad

bind

er (

a fa

ctor

y bl

ende

d hy

drau

lic b

inde

r sp

ecif

ical

lyfo

r ro

ads

and

pave

men

ts)

HB

-hy

drau

lic b

inde

r (a

mat

eria

l tha

t ha

rden

s bo

th u

nder

wat

er a

nd in

air

,w

hen

mix

ed w

ith

wat

er)

e.g.

cem

ent,

HR

B,an

d th

e lim

e/PF

A

or li

me/

GG

BS c

ombi

nati

on.

SHB

-so

il tr

eate

d or

sta

bilis

ed b

y an

hy

drau

lic b

inde

rO

MC

-op

tim

um m

oist

ure

cont

ent

MC

V -

moi

stur

e co

ndit

ion

valu

e

4.C

ons

titu

ents

4.1

Soil

Soil

for

SHB

sh

all

be

natu

rally

o

ccur

ring

mat

eria

l,ar

tifi

cial

mat

eria

l,re

cycl

ed m

ater

ial,

or a

com

bina

tion

of

thes

e.W

hen

wet

sie

ved,

not

less

tha

n 95

% o

f th

e so

il sh

all

pass

the

63m

m s

ieve

.O

rgan

ic m

atte

r,if

pre

sent

,sh

all

not

adve

rsel

y af

fect

the

per

form

ance

of

the

mix

ture

.If

th

is

exce

eds

2%

by

w

eigh

t,la

bora

tory

tes

ts s

hall

be c

arri

ed o

ut t

o co

nfir

mth

at t

he r

equi

red

stre

ngth

can

be

achi

eved

.

Soil,

part

icul

arly

tha

t co

ntai

ning

or

susp

ecte

dof

co

ntai

ning

su

lfat

es

or

othe

r po

tent

ially

disr

upti

ve m

ater

ial,

shal

l be

dee

med

sui

tabl

efo

r tr

eatm

ent

prov

ided

the

req

uire

men

ts o

fcl

ause

8.1

3 ar

e sa

tisf

ied

both

at

labo

rato

rym

ixtu

re d

esig

n st

age

and

duri

ng c

onst

ruct

ion.

4.2

Lim

e Li

me

shal

l be

quic

klim

e to

EN

459-

1:20

01 a

ndth

e fo

llow

ing

spec

ific

atio

n:C

aO +

MgO

con

tent

> 8

0%M

gO c

onte

nt <

10%

Reac

tivi

ty w

ith

wat

er,e

stab

lishe

d in

ac

cord

ance

wit

h EN

459-

2,sh

all a

chie

ve a

te

mpe

ratu

re o

f at

leas

t 60

deg

rees

C

wit

hin

25 m

inut

es.

(Les

s re

acti

ve Q

uick

limes

may

be

used

pr

ovid

ing

com

plet

e hy

drat

ion

is e

nsur

ed

befo

re f

inal

com

pact

ion.

) Pa

rtic

le s

ize:

For

in-s

itu

trea

tmen

ts 1

00%

pass

ing

a 10

mm

sie

ve a

nd a

t le

ast

95%

pas

sing

a 5m

m s

ieve

or

fine

r.W

here

air

born

e du

st i

sle

ss c

riti

cal,

such

as

a se

aled

sta

tic

mix

ing

plan

t,fi

ner

grad

es o

f qu

ickl

ime

may

be

used

.W

here

a s

eale

d m

ixin

g pl

ant

is t

o be

use

dan

d du

st is

not

a c

once

rn H

ydra

ted

Lim

e to

BS

EN 4

59-1

:200

1,C

L90

may

be

cons

ider

ed.T

hedr

ying

rea

ctio

n ac

hiev

ed w

ith

Qui

cklim

e w

illno

t be

pre

sent

usi

ng H

ydra

ted

Lim

e.

4.3

GG

BSG

GBS

sha

ll co

mpl

y w

ith

BS66

99:1

992.

4.4

PFA

PFA

sh

all

com

ply

wit

h BS

38

92

part

1

orEN

450.

The

Engi

neer

may

als

o ap

prov

e dr

y or

con

diti

on

ed

(wet

) ru

n-o

f-st

atio

n

ash

prov

idin

g re

cen

t su

ppli

er

cert

ific

ates

indi

cati

ng

the

phys

ical

an

d ch

emic

alch

arac

teri

stic

s of

the

mat

eria

l ar

e av

aila

ble.

Befo

re u

se,c

ondi

tion

ed P

FA s

hall

be s

tore

d fo

rat

leas

t 3

days

at

min

imum

moi

stur

e co

nten

tof

10

%

and

scre

ened

to

re

mov

e pa

rtic

les

grea

ter

than

10m

m.

4.5

HR

B H

RB

shal

l com

ply

wit

h D

D E

NV

132

82:2

000.

4.6

Cem

ent

Cem

ent

shal

l be

por

tlan

d ce

men

t co

mpl

ying

wit

h BS

EN

197

-1:2

000.

4.7

Wat

er

Wat

er

shal

l no

t co

ntai

n co

mpo

nent

s th

ataf

fect

the

per

form

ance

of

the

SHB.

5.C

om

posi

tio

n

5.1

SHB

shal

l be

m

ade

from

co

nsti

tuen

tsse

lect

ed fr

om s

ecti

on 4

usi

ng p

ropo

rtio

ns t

hat

sati

sfy

the

requ

irem

ents

of

this

sec

tion

and

the

perf

orm

ance

req

uire

men

ts o

f se

ctio

n 8,

part

icu

larl

y n

oti

ng

the

req

uir

emen

ts

of

sect

ions

8.

10,

8.11

an

d 8.

12

on

stre

ngth

,tr

affi

ckin

g an

d fr

ost

resi

stan

ce r

espe

ctiv

ely.

5.2

Unl

ess

othe

rwis

e ag

reed

by

the

Engi

neer

,th

e m

inim

um p

ropo

rtio

ns o

f a

cons

titu

ent

inan

y m

ix,b

y dr

y w

eigh

t of

the

tot

al m

ix,s

hall

be;

lime

1.5%

,GG

BS 3

%,P

FA 5

% (8

% in

the

cas

e of

cond

itio

ned

PFA

),H

RB 3

% a

nd c

emen

t 3%

.

6.M

etho

d St

atem

ent

6.1

Bef

ore

co

mm

ence

men

t o

f th

e m

ain

wor

ks,

the

cont

ract

or

shal

l pr

ovid

e a

full

met

hod

stat

emen

t.Th

is

shal

l sp

ecif

y th

eo

pera

tio

nal

pro

cedu

re

for

the

wo

rks,

site

prep

arat

ion,

type

of

plan

t an

d pr

ogra

mm

e.Sp

ecif

ic

deta

ils

shal

l be

su

pplie

d re

gard

ing

esti

mat

ed

dura

tion

s an

d in

terv

als

betw

een

the

mai

n

stag

es

of

the

trea

tmen

t,li

me

amel

iora

tion

st

ages

(i

f ap

plic

able

) an

d th

ehy

drau

lic

bin

der

addi

tio

n,

curi

ng

and

prot

ecti

on.

6.2

In

part

icu

lar,

the

met

ho

d st

atem

ent

shou

ld s

peci

fy t

he p

roce

dure

s,co

ntro

ls a

ndpr

odu

ctio

n

chec

ks

wit

h

resp

ect

to

site

prep

arat

ion,

pow

der

spre

adin

g,pu

lver

isat

ion

(if

appl

icab

le),

wat

er a

ddit

ion,

MC

V,d

epth

of

mix

ing

,co

mpa

ctio

n,

insi

tu

den

sity

mea

sure

men

t,le

vel

cont

rol,

fini

shin

g ro

lling

,cu

ring

and

pro

tect

ion.

6.3

The

met

hod

stat

emen

t sh

all

incl

ude

the

inte

nded

mix

ture

pro

port

ions

,the

sup

port

ive

data

to

just

ify

the

prop

orti

ons,

the

moi

stur

eco

nten

t an

d re

late

d M

CV

lim

its

and

bind

erad

diti

ons

for

all s

tage

s of

the

wor

k.

6.4

The

met

hod

stat

emen

t sh

all

incl

ude

asa

mpl

e re

cord

she

et t

o be

com

plet

ed f

or e

ach

con

stru

ctio

n

bay

deta

ilin

g;

con

stru

ctio

nti

mes

,sa

mpl

e an

d te

st l

ocat

ions

and

che

ckre

sult

s fo

r al

l co

ntro

l pa

ram

eter

s in

clud

ing

thos

e in

cla

use

6.2.

6.5

The

mai

n w

orks

sha

ll no

t co

mm

ence

unt

ilre

ceip

t of

a s

atis

fact

ory

met

hod

stat

emen

tan

d re

cord

she

et.

7.D

emo

nstr

atio

n ar

ea

7.1

Prio

r to

th

e co

mm

ence

men

t of

th

e m

ain

wo

rks,

the

con

trac

tor

shal

l u

nde

rtak

e a

dem

on

stra

tio

n

area

o

f at

le

ast

80

0m

2

conf

orm

ing

to

his

met

hod

stat

emen

t.Th

ede

mon

stra

tion

are

a sh

all

cons

ist

of a

t le

ast

2fu

ll-w

idth

bay

s so

as

to i

nclu

de a

tra

nsve

rse

end-

of-b

ay jo

int.

7.2

The

dem

onst

rati

on a

rea

may

be

acce

pted

into

the

perm

anen

t w

orks

wit

h th

e ag

reem

ent

ofth

e En

gine

er.

8.M

ixtu

re P

erfo

rman

ce a

nd C

ons

truc

tio

nRe

quir

emen

ts

The

freq

uenc

y of

tes

ts,c

ontr

ols

and

chec

ks s

hall

bein

acc

orda

nce

wit

h 8.

14.

8.1

Spre

ad r

ates

Wit

h th

e ex

cept

ion

of c

ondi

tion

ed P

FA,w

hich

sha

llbe

spr

ead

by b

lade

,dry

pow

ders

sha

ll be

spr

ead

bypu

rpos

e-m

ade

spre

ader

s at

ra

tes

high

en

ough

to

avoi

d no

n-un

ifor

mit

y an

d lo

w e

noug

h to

min

imis

edi

spla

cem

ent

by p

lant

tha

t tr

aver

se t

he a

rea

just

spre

ad.T

his

will

nor

mal

ly b

e be

twee

n th

e ra

nges

8 –

20 k

g/m

2 .

8.2

Am

elio

rati

on

Whe

re

lime

is

used

to

am

elio

rate

(b

reak

do

wn)

cohe

sive

soi

ls p

rior

to

the

addi

tion

of G

GBS

,PFA

,HR

Bor

cem

ent,

it s

hall

be a

dded

and

mix

ed w

ith

the

soil

not

less

tha

n 24

hou

rs n

or m

ore

than

72

hour

s be

fore

the

subs

eque

nt a

ddit

ion.

For

sulf

ate

bear

ing

cohe

sive

soils

thi

s pe

riod

sha

ll be

bet

wee

n 48

and

72

hour

s.D

urin

g th

is

peri

od

it

mus

t be

en

sure

d th

at

any

quic

klim

e ad

ded

to t

he s

oil

is f

ully

hyd

rate

d.Th

em

oist

ure

cont

ent

at t

his

stag

e sh

all b

e no

t le

ss t

han

the

OM

C (

or m

ore

than

the

equ

ival

ent

MC

V)

for

the

lime

mod

ifie

d m

ixtu

re

dete

rmin

ed

in

acco

rdan

cew

ith

the

2.5k

g Pr

octo

r m

etho

d of

BS1

924.

8.3

Mix

ing

and

pulv

eris

atio

n M

ixin

g an

d pu

lver

isat

ion

shal

l be

car

ried

out

by

one

or

mor

e pa

sses

of

a

purp

ose

mad

e m

ixer

un

til

unif

orm

ity

is a

chie

ved.

In t

he c

ase

of a

mel

iora

tion

of

cohe

sive

soi

ls (

8.2)

,the

deg

ree

of p

ulve

risa

tion

of t

hefu

ll de

pth

of t

reat

men

t af

ter

lime

addi

tion

sha

ll be

inex

cess

of

30%

,or

othe

r ag

reed

val

ue,d

eter

min

ed i

nac

cord

ance

wit

h BS

1924

.Fo

r co

hesi

ve m

ixtu

res

afte

r fi

nal

mix

ing

of t

he f

inal

cons

titu

ent

addi

tion

,th

e de

gree

of

pulv

eris

atio

n of

the

full

dept

h of

lay

er s

hall

be i

n ex

cess

of

60%

or

othe

r ag

reed

val

ue.

NO

TE:

The

mea

sure

men

t o

f th

e de

gree

o

fpu

lver

isat

ion

may

be

diff

icul

t w

ith

mix

ture

s at

or

wet

ter

than

the

OM

C.

8.4

Dep

th o

f m

ixin

g.Th

e de

pth

of m

ixin

g at

all

rele

vant

sta

ges

of t

hepr

oces

s sh

all

be c

heck

ed u

sing

sui

tabl

e re

fere

nce

stat

ion

s to

en

sure

th

at

afte

r fi

nal

tr

im

and

com

pact

ion,

the

fina

l th

ickn

ess

of t

he l

ayer

is

tosp

ecif

icat

ion.

8.5

Fina

l wat

er c

ont

ent

At

fin

al

com

pact

ion

,th

e m

ois

ture

co

nte

nt

for

gran

ular

mix

ture

s sh

all

be n

ot l

ess

than

0.9

OM

Cde

term

ined

in a

ccor

danc

e w

ith

the

vibr

atin

g ha

mm

erm

etho

d of

BS1

924,

and

for

cohe

sive

mix

ture

s no

tle

ss t

han

the

OM

C (

or m

ore

than

the

equ

ival

ent

MC

V)

dete

rmin

ed i

n ac

cord

ance

wit

h th

e 2.

5 kg

Proc

tor

met

hod

of B

S192

4.

8.6

Co

mpa

ctio

nFi

nal

com

pact

ion,

incl

udin

g fi

nish

ing

rolli

ng,s

hall

beco

mpl

eted

wit

hin

2 ho

urs

of m

ixin

g of

cem

ent,

4ho

urs

for

GG

BS a

nd H

RB,

and

6 ho

urs

for

PFA

.Whe

rea

sing

le p

owde

r is

add

ed o

ver

2 op

erat

ions

,the

tim

esh

all a

pply

fro

m t

he m

ixin

g of

the

fir

st a

pplic

atio

n.

8.7

Surf

ace

fini

shO

n co

mpl

etio

n of

fin

al c

ompa

ctio

n,th

e su

rfac

e of

the

laye

r sh

all

be w

ell

clos

ed,f

ree

from

mov

emen

tun

der

com

pact

ion

plan

t,an

d fr

ee f

rom

rid

ges,

crac

ks,

loos

e m

ater

ial,

segr

egat

ed a

reas

,pot

hol

es,r

uts

and

othe

r de

fect

s.O

n no

acc

ount

is it

per

mis

sibl

e to

add

thin

laye

rs o

f m

ater

ial t

o bu

ild u

p ar

eas

that

are

low

once

rol

ling

has

star

ted.

8.8

Den

sity

The

full

dept

h of

the

lay

er s

hall

be c

ompa

cted

to

anav

erag

e de

nsit

y of

not

less

tha

n 95

% o

f th

e av

erag

efr

esh

wet

den

sity

of

the

stre

ngth

spe

cim

ens

mad

e in

acco

rdan

ce w

ith

clau

se 8

.10.

The

insi

tu w

et d

ensi

tysh

all

be m

easu

red

usin

g a

nucl

ear

dens

ity

gaug

e in

acco

rdan

ce w

ith

BS19

24:

1990

.Th

e av

erag

e in

situ

dens

itie

s sh

all

rela

te t

o th

e m

ean

of t

he r

esul

ts f

oron

e da

y pr

oduc

tion

sam

ples

spe

cifi

ed in

Tab

le S

HB.

8.9

Seal

ing

Imm

edia

tely

on

com

plet

ion

of c

ompa

ctio

n,th

e su

rfac

eof

the

lay

er s

hall

be s

eale

d w

ith

a bi

tum

en e

mul

sion

appl

ied

at

the

rate

of

0.

5 lit

re/m

2 .A

lter

nati

vely

anot

her

appr

oved

pro

duct

at

an e

quiv

alen

t ap

plic

atio

nm

ay b

e us

ed o

r a

sing

le s

urfa

ce d

ress

ing

(see

8.1

1) t

oac

hiev

e a

cont

inuo

us a

nd c

onsi

sten

t se

al a

cros

s th

ew

hole

are

a of

the

wor

ks.

8.10

Str

engt

h St

reng

th

shal

l be

m

easu

red

usin

g sa

mpl

es

of

the

mix

ture

rep

rese

ntin

g th

e fu

ll de

pth

of t

he l

ayer

aft

erfi

nal

mix

ing.

Gro

ups

of

cubi

c or

1:

1 cy

lindr

ical

spec

imen

s re

pres

enti

ng

one

day’

s w

ork

shal

lde

term

ine

the

aver

age

com

pres

sive

str

engt

h.Th

eysh

all

be m

ade

in r

igid

pla

stic

(H

DPE

) m

ould

s an

dco

mpa

cted

to

refu

sal

wit

hin

one

hour

of

the

fina

lco

nsti

tuen

t ad

diti

on

in

acco

rdan

ce

wit

h ei

ther

BS19

24 o

r us

ing

MC

V a

ppar

atus

.The

spe

cim

ens

shal

lbe

sea

led

and

cure

d as

des

crib

ed in

BS1

924-

2,se

ctio

n4.

1.6,

usin

g th

e re

com

men

dati

ons

for

cem

ent

to c

over

SHB

that

con

tain

cem

ent

and

the

reco

mm

enda

tion

sfo

r lim

e to

cov

er S

HB

that

do

not

cont

ain

cem

ent.

The

stre

ngth

s re

cord

ed s

hall

be n

ot l

ess

than

1 M

Pa o

rot

her

spec

ifie

d va

lue

(see

8.1

1 an

d 8.

12).

NO

TE 1

:W

hate

ver

the

age

of t

esti

ng a

nd c

urin

gco

ndit

ions

,it

shou

ld b

e no

ted

that

SH

B m

ade

from

hig

h

plas

tici

ty

clay

s m

ay

stru

ggle

to

re

ach

com

pres

sive

str

engt

hs o

f 1

MPa

.

NO

TE 2

:A

s an

alt

erna

tive

to,

or in

con

junc

tion

wit

h,co

mpr

essi

ve s

tren

gth,

labo

rato

ry o

r in

situ

sur

face

stif

fnes

s ca

n

be

spec

ifie

d.Fo

r gu

idan

ce,

inco

mpa

riso

n w

ith

the

abov

e co

mpr

essi

ve s

tren

gth,

labo

rato

ry N

AT s

tiff

ness

wou

ld r

ange

upw

ards

fro

m10

00 M

Pa a

nd,d

epen

ding

on

age

and

tem

pera

ture

,in

situ

su

rfac

e st

iffn

ess

fro

m

20

0

MPa

.M

CV

appa

ratu

s h

as

been

fo

un

d su

itab

le

for

the

man

ufac

ture

of

NAT

sti

ffne

ss s

peci

men

s.

NO

TE

3:A

s a

furt

her

alte

rnat

ive

to

com

pres

sive

stre

ngth

,so

aked

C

BR

test

ing

may

be

em

ploy

ed.

Typi

cally

,a

CBR

val

ue o

f 10

0% m

ay b

e co

nsid

ered

equi

vale

nt t

o 1

MPa

com

pres

sive

str

engt

h.

8.11

Tra

ffic

abili

ty

Unl

ess

agre

ed

othe

rwis

e,co

nstr

ucti

on

plan

t an

dtr

affi

c sh

all n

ot r

un o

n th

e la

yer

othe

r th

an t

o en

able

cons

truc

tion

of

the

over

lyin

g la

yer.

Not

e:Ex

peri

ence

su

gges

ts

that

SH

B m

eeti

ng

the

stre

ngth

lev

el o

f 1

MPa

spe

cifi

ed i

n 8.

10 s

houl

dpr

ovid

e a

suff

icie

ntly

rob

ust

laye

r fo

r si

te t

raff

icki

ngas

soci

ated

w

ith

the

next

la

yer

and

poss

ibly

fo

rdr

aina

ge a

nd e

dge

deta

il w

ork.

Whe

re t

raff

icki

ng w

illbe

lig

ht,a

spe

cifi

ed s

tren

gth

as l

ow a

s 0.

5 M

Pa m

aysu

ffic

e.W

here

hea

vy t

raff

icki

ng i

s ex

pect

ed t

hen

asp

ecif

ied

stre

ngt

h

of

at

leas

t 1

.5

MPa

w

ill

bene

cess

ary.

In t

he l

ater

cas

e,co

nsid

erat

ion

shou

ld b

egi

ven

to t

he a

pplic

atio

n of

a s

urfa

ce d

ress

ing. lime

thin

k

21425_specPav1_sheet 13/1/06 12:12 pm Page 1

Page 2: Model Specification for Pavement Layers made 8. … Specification for Pavement Layers made ... furnace slag,pulverised fuel ash,cement and hydraulic road binder. ... fresh wet density

spec

ific

atio

n data

BR

ITIS

H L

IME

AS

SO

CIA

TIO

N

Qua

rry

Pro

duct

s A

ssoc

iatio

n,G

illin

gham

Hou

se,

38-4

4 G

illin

gham

Str

eet,

Lond

on

SW

1V 1

HU

Te

l 020

7 96

3 80

00

Fax

020

7 96

3 80

01

emai

l inf

o@qp

a.or

g

3pa

vem

ents

The

Brit

ish

Lim

e A

ssoc

iati

on is

one

of

the

cons

titu

ent

bodi

es o

f th

e Q

uarr

y Pr

oduc

ts A

ssoc

iati

on,t

he t

rade

asso

ciat

ion

for

the

aggr

egat

e,as

phal

t an

d re

ady-

mix

edco

ncre

te in

dust

ries

.w

ww

.bri

tish

lime

.org

8.12

Fro

st r

esis

tanc

e Th

e SH

B la

yer

shal

l ha

ve s

uffi

cien

t st

reng

th,

prot

ecti

on o

r bi

nder

add

itio

n to

wit

hsta

nd

surf

ace

fro

st

effe

cts

duri

ng

and

afte

r

cons

truc

tion

.In

add

itio

n it

sha

ll be

abl

e to

wit

hsta

nd f

rost

hea

ve if

use

d w

ithi

n th

e zo

ne

of f

rost

pen

etra

tion

whe

re g

roun

d w

ater

can

be d

raw

n-up

into

the

SH

B la

yer.

If t

he d

esig

n in

dica

tes

the

SHB

laye

r w

ill b

e

wit

hin

450m

m o

f th

e ro

ad s

urfa

ce,o

r 35

0mm

if t

he a

nnua

l fro

st in

dex

of t

he s

ite

is le

ss t

han

50

,th

en

resi

stan

ce

to

fro

st

mu

st

be

dete

rmin

ed in

acc

orda

nce

wit

h BS

1924

:Par

t 2

and

the

amen

ded

BS81

2 te

st.

This

is

in a

ccor

danc

e w

ith

clau

se 6

02.1

9 of

the

Spec

ific

atio

n fo

r H

ighw

ay W

orks

.Fr

ost

susc

epti

bilit

y sh

ould

be

dete

rmin

ed a

fter

28

days

cur

e bu

t th

is m

ay b

e ex

tend

ed t

o 56

day

s

if t

he m

ater

ial

is s

low

to

gain

str

engt

h an

d

deve

lop

fros

t re

sist

ance

.

Not

e 1:

It

is

advi

sed

that

du

ring

co

nstr

ucti

on

and

prio

r to

ove

rlay

ing,

the

tem

pera

ture

of

SHB

shal

l not

fal

l bel

ow 5

ºC.I

n or

der

to a

llow

SH

B

to g

ain

adeq

uate

str

engt

h be

fore

the

fir

st

fro

sts,

it

is

reco

mm

ende

d th

at

SHB

cons

truc

tion

sha

ll no

t be

und

erta

ken

afte

r th

e

end

of

Oct

obe

r an

d in

th

e ca

se

of

the

lime/

PFA

bin

der

com

bina

tion

,no

t af

ter

the

end

of S

epte

mbe

r.

8.13

Vo

lum

e st

abili

ty

Vol

ume

stab

ility

tes

ting

of

the

mix

ture

sha

ll be

car

ried

out

in a

ccor

danc

e w

ith

the

imm

ersi

on t

est

inBS

1924

and

sat

isfy

the

req

uire

men

ts o

f Ta

ble

VS.

The

seal

ed c

urin

g pe

riod

pri

or t

o im

mer

sion

sha

llbe

28

days

and

the

imm

ersi

on p

erio

d 32

day

s.

TABL

E V

S

SHB

type

Imm

erse

d st

reng

th in

MPa

%ag

e vo

lum

etri

c sw

ellin

gC

ohes

ive

> 6

5% o

f no

n-im

mer

sed

stre

ngth

at

60 d

ays

< 2

Gra

nula

r>

80%

of

non-

imm

erse

d st

reng

th a

t 60

day

s<

1

NO

TE:T

he B

S te

st c

an b

e ca

rrie

d ou

t on

cyl

inde

rs a

s w

ell a

s cu

bes

and

can

be c

arri

ed o

ut a

t ea

rlie

rag

es w

ith

or w

itho

ut a

ccel

erat

ed c

urin

g if

con

veni

ent.

8.14

Tes

ting

fre

quen

cyC

ompl

ianc

e w

ith

the

abov

e re

quir

emen

ts s

hall

be d

eter

min

ed i

n ac

cord

ance

wit

h Ta

ble

SHB

atlo

cati

ons

agre

ed w

ith

the

Engi

neer

.

TABL

E SH

B

Test

/co

ntro

lRe

fere

nce

clau

seSu

gges

ted

freq

uenc

y (m

ay b

e m

odi

fied

eit

her

way

dep

endi

ng o

n pe

rfo

rman

ce a

nd t

he

natu

re o

f th

e jo

b)O

N T

HE

CO

NST

ITU

ENTS

:So

il:m

/c,p

last

icit

y or

gani

cs1

per

1,00

0m2

carr

ied

out

and

repo

rted

inan

d to

tal p

oten

tial

sul

fate

4.1

adva

nce

of t

he w

orks

Add

ed c

onst

itue

nts:

4.2,

4.3,

4.4,

Wee

kly

Supp

lier

cert

ific

ate

4.5,

4.6

Add

ed c

onst

itue

nts:

8.1

3 pe

r 50

0m2

Spre

ad r

ates

ON

TH

E SH

B:M

oist

ure

cont

ent/

MC

V8.

21

per

500m

2bu

t no

t le

ss t

han

3 pe

r da

y af

ter

lime

addi

tion

Moi

stur

e co

nten

t/M

CV

8.5

1 pe

r 50

0m2

but

not

less

tha

n 6

per

day

at f

inal

com

pact

ion

If a

pplic

able

,pul

veri

sati

on8.

31

per

500m

2bu

t no

t le

ss t

han

3 pe

r da

yaf

ter

lime

addi

tion

If a

pplic

able

,pul

veri

sati

on8.

31

per

500m

2bu

t no

t le

ss t

han

3 pe

r da

yat

fin

al c

ompa

ctio

n D

epth

of

mix

ing

at a

ll8.

41

per

500m

2bu

t no

t le

ss t

han

5 pe

r da

y.re

leva

nt s

tage

sIn

-sit

u de

nsit

y8.

8D

itto

Com

pres

sive

str

engt

h8.

101

per

500m

2bu

t no

t le

ss t

han

3 pe

r da

y*Fi

nal l

evel

8.4

To b

e ag

reed

but

for

a r

oad

sugg

est;

Gri

d:10

m lo

ng,2

m t

rans

vers

eV

olum

e st

abili

ty8.

131

pair

per

300

0 m

2bu

t no

t le

ss t

han

1 pa

ir p

er d

ay*

*

Thus

a m

inim

um o

f 5

stre

ngth

spe

cim

ens

are

mad

e pe

r da

y;th

e av

erag

e w

et d

ensi

ty o

f th

e 5

prov

idin

g th

e ta

rget

den

sity

for

the

insi

tu d

ensi

ty.

Rev

:12

July

200

4

BR

ITIS

H L

IME

AS

SO

CIA

TIO

N

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