cementitious stabilisation of road construction materials: quo vadis

CEMENTITIOUS STABILISATION CEMENTITIOUS STABILISATION OF ROAD CONSTRUCTION OF ROAD CONSTRUCTION MATERIALS: QUO VADISMATERIALS: QUO VADIS

Phil Paige-Green,

CSIR-Transportek, Pretoria

Frank Netterberg

Consultant

INTRODUCTIONINTRODUCTION

Stabilisation of marginal materials is still an important part of road building in RSA

Will probably become more important as good materials are depleted

Specification of stabilisation is based on:– COLTO Standard Specs for R&B (1996) – with assistance from Draft TRH 13 (1986)

INTRODUCTIONINTRODUCTION Cement stabilisation experience incorporated in

COLTO and TRH13 was based mainly on the use of:

– Ordinary Portland Cement (SABS 471)– PBFC (SABS 626)– Portland cement blends (SABS 831)– Portland flyash cement (SABS 1466)

Things have changed !!

SABS ENV 197-1SABS ENV 197-1

In 1992, became a European pre-standard (ENV) After 3 years should be upgraded to European

standard (EN) ?? Adopted “as is” by SABS in 1996 for RSA Applicable to “common cements” Similar spec for masonry cements (SABS ENV

413-1) Concentrate on SABS ENV 197-1 as this is most

relevant for roads

NEW REQUIREMENTSNEW REQUIREMENTS Totally different classification system 5 cement types

– 9 groups (depend on additive) 19 subgroups (depend on composition)

Also classified by strength and rate of strength gain (6 additional permutations)

CLASSIFICATIONCLASSIFICATION I Portland cement II Other Portland cements

Portland slag cement Portland silica fume cement Portland flyash cement Portland limestone cement Portland composite cement

III Blastfurnace cement IV Pozzolanic cement V Composite cement

Strength requirementsStrength requirements

Strength class

Compressive strength (MPa)

Early strength Standard strength

2 days 7 days 28 days

32.5 - ≥ 16.0 ≥ 32.5 ≤ 52.5

32.5R ≥ 10.0 -

42.5 ≥ 10.0 - ≥ 42.5 ≤ 62.5

42,5R ≥ 20.0 -

52.5 ≥ 20.0 - ≥ 52.5 -

52.5R ≥ 30.0 -

STANDARD DESIGNATIONSTANDARD DESIGNATION

Cement ENV 197-1 CEM I 32.5– (equiv to OPC ?)

Cement ENV 197-1 CEM II/A-S 42.5

CHEMICAL PROPERTIESCHEMICAL PROPERTIES

SABS 471 SABS ENV 197-1

Lime sat factor 0.66 -1.02 CaO/SiO2 ≥ 2

MgO cement ≤ 5% MgO clinker ≤ 5%

Max SO3 = 3.0 – 3.5 % Max SO3 = 3.5 – 4.0 % (4.5)

Max LoI = 4 % Max LoI = 5 %

Max insoluble residue = 2.5% Max insoluble residue = 5%

Chloride N/S Max chloride 0.1%

Pozzolanicity N/S Pozzolanicity - Yes

PHYSICAL PROPERTIESPHYSICAL PROPERTIES

Property SABS 471 ENV 197-1

Max % >212 μm 1.2

0.5 (RH)

N/S

Min specific surface area (cm2/g)

2250

3250 (RH)

N/S

Min UCS (MPa) 3 days

7 days

16 21 (RH)

24 28 (RH)

Earlier table

Min transverse str (MPa)

3 days

7 days

1.8 2.8 (RH)

2.8 3.8 (RH)

N/S

N/S

PHYSICAL PROPERTIES (cont)PHYSICAL PROPERTIES (cont)

Property SABS 471 ENV 197-1

Setting times:

Min initial (min)

Max final (hrs)

45 45 (RH)

10 10 (RH)

45 – 60

N/S

Soundness:

Max expansion (mm)

10 10 (RH) 10

STRENGTHSTRENGTH

0

10

20

30

40

50

60

0 5 10 15 20 25 30

Days

Stre

ngth

(MPa

)

PortlandcementRH Portlandcement32.5

32.5R

42.5

42.5R

52.5

52.5R

Linear (52.5R)

Linear (42.5R)

Linear (42.5)

Linear (32.5R)

Linear (52.5)

Strength requirementsStrength requirements

Strength class

Compressive strength (MPa)

Early strength Standard strength

2 days 7 days 28 days

32.5 - ≥ 16.0 ≥ 32.5 ≤ 52.5

32.5R ≥ 10.0 -

42.5 ≥ 10.0 - ≥ 42.5 ≤ 62.5

42,5R ≥ 20.0 -

52.5 ≥ 20.0 - ≥ 52.5 -

52.5R ≥ 30.0 -

CHEMICAL PROPERTIESCHEMICAL PROPERTIES

SABS 471 SABS ENV 197-1

Lime sat factor 0.66 -1.02 CaO/SiO2 ≥ 2

MgO cement ≤ 5% MgO clinker ≤ 5%

Max SO3 = 3.0 – 3.5 % Max SO3 = 3.5 – 4.0 % (4.5)

Max LoI = 4 % Max LoI = 5 %

Max insoluble residue = 2.5% Max insoluble residue = 5%

Chloride N/S Max chloride 0.1%

Pozzolanicity N/S Pozzolanicity - Yes

PHYSICAL PROPERTIESPHYSICAL PROPERTIES

Property SABS 471 ENV 197-1

Max % >212 μm 1.2

0.5 (RH)

N/S

Min specific surface area (cm2/g)

2250

3250 (RH)

N/S

Min UCS (MPa) 3 days

7 days

16 21 (RH)

24 28 (RH)

Earlier table

Min transverse str (MPa)

3 days

7 days

1.8 2.8 (RH)

2.8 3.8 (RH)

N/S

N/S

PHYSICAL PROPERTIES (cont)PHYSICAL PROPERTIES (cont)

Property SABS 471 ENV 197-1

Setting times:

Min initial (min)

Max final (hrs)

45 45 (RH)

10 10 (RH)

45 – 60

N/S

Soundness:

Max expansion (mm)

10 10 (RH) 10

STRENGTHSTRENGTH

0

10

20

30

40

50

60

0 5 10 15 20 25 30

Days

Stre

ngth

(MPa

)

PortlandcementRH Portlandcement32.5

32.5R

42.5

42.5R

52.5

52.5R

Linear (52.5R)

Linear (42.5R)

Linear (42.5)

Linear (32.5R)

Linear (52.5)