1

CONTRIBUTION TO THE DEFINITION OF CONDITIONS OF USE OF THE MUNICIPAL SOLID WASTE SLAG IN EMBANKMENTS AND IN CAPPING LAYERS

Eric EVAIN – CETE Normandie Centre – CERAlain QUIBEL – CETE Normandie Centre – CERJean Claude AURIOL – Laboratoire Central des Ponts et Chaussées

2

OBJECTIVES OF THE RESEARCH PROGRAM(LCPC)

1) To elaborate a geotechnical characterization of the MSWS.

2) To define the conditions of use of theMSWS in embankments and in cappinglayers without treatment

3) To check the interpretation in control compaction with dynamic penetrometer.

3

Today in France

- GTR classification of MSW Slag : Class F61This class is characterized with an unburnt rate at 500°C < 5%

- Objectives of density- Embankments: q4 objective average ρd > 95% ρd SP

bottom ρd > 92% ρd SP

- Capping layer: q3 objective average ρd > 98.5% ρd SP

bottom ρd > 96% ρd SP

- Roadbase: q2 objective average ρd > 97% ρd MP

bottom ρd > 95% ρd MP

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GEOTECHNICAL CHARACTERIZATION OF THE MSW SLAG

• Moisture contentinfluence of the oven temperature.Measures at 35°C, 50°C and 105°C show that a measure of the moisture content in the

same conditions than those for the conventional materials (105°C) is convenient.influence of the grain sizeThe moisture content is deeply included in the fine size part of the soil (0/10mm)

influence of the compactionTests made with Standard Proctor energy show that it doesn't release enough water to generate a change of hydrous state of the MSWS.

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GEOTECHNICAL CHARACTERIZATION OF THE MSW SLAG

•Variations with the productionThe Proctor curves obtained from January to August 2002 on different productions of the same site show that the maximal dry density varies from 1,54 to 1,64 t/m3 and that the optimum moisture content varies from 15,4 to 21,1 %.

Standard Proctor tests on MSWS

1.4

1.45

1.5

1.55

1.6

1.65

1.7

1.75

1.8

5 7 9 11 13 15 17 19 21 23 25 27 29

Moisture content W(%)

Dry

den

sity

(t/m

3)

Standard Proctor test #1

Standard Proctor test #2

Standard Proctor test #3

Standard Proctor test #4

Standard Proctor test #5

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GEOTECHNICAL CHARACTERIZATION OF THE MSW SLAG

• Homogeneity of the material4 standard Proctor tests have been made on the same sample from the same stock.

W(%) ρd(t/m3) W(%) ρd(t/m

3) W(%) ρd(t/m3) W(%) ρd(t/m

3)Optimum Dry Density 19.8 1.54 21 1.53 19.0 1.61 18.3 1.60

Test 1 Test 2 Test 3 Test 4The variations of the Standard Proctor test on the same stock, are alike those of the whole production

1 . 4

1 . 5

1 . 6

1 . 7

1 . 8

0 5 1 0 1 5 2 0 2 5 3 0

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GEOTECHNICAL CHARACTERIZATION OF THE MSW SLAG

• An evolutionary materialI-Evolutivity of the material3 curves are obtained: one with Standard Proctor energy, one with Modified Proctor

energy and one with 1/3 of the Standard Proctor energy. Then, at the optimummoisture content value of every curve, 10 tests are repeated in the mold with the same sample put back every time, to check the evolution of the dry density

1.723

1.879

1.422

1.562

1.472

1.645

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Moisture content (%)

Dry

Den

sity

(t.m

-3)

1/3 Standard Proctor10 repetitionsStandard Proctor10 repetitionsModified Proctor10 repetitions

The 10 repetitions show the strong evolution of densities at the optimum point, whatever are the energies of compaction. The asymptote of evolution is not yet obtained after the 10th test.

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GEOTECHNICAL CHARACTERIZATION OF THE MSW SLAG

0

10

20

30

40

50

60

70

80

90

100

0.01 0.1 1 10 100

Sieve (mm)

Pas

sing

(%)

1/3 St. Proctor : Before tests

1/3 St. Proctor : After tests

St. Proctor : Before tests

St. Proctor : After tests

Mod. Proctor Before tests

Mod. Proctor : After tests

Grain size curves made before the first test and after the tenth test show that the relative material passing increase to 5mm is 33 %, and the one to 2mm is 50 %, with the Modified Proctor energy.

This evolution is checking the use of MSWS for the higher compaction objectives (>=q2).

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CONDITIONS OF USE OF THE MSW SLAG

Characterization of the MSWS used (Rouen)Tests have been made with a MSWS having 3 months of maturation from a homogeneous

stock. The MSWS comes from the MSWS plant of ROUEN. The Standard Proctor values are: ρdMAX = 1,57 t/m3 and WOMC = 19,5%.

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CONDITIONS OF USE OF THE MSW SLAG

Experimentation schemeThe studied parameters are: § The moisture content of the material,

§ The energy of compaction (number of roller passes),§ The thickness of layers.

3 Test sections have been made at CER.Sections 1 and 2 concern the influence of the layer thickness, and sections 2, 3 and 5 are devoted to the influence of the moisture content.

The experiment progress had two phases (A and B). Sections 1, 2 and 3 have been first placed. After dismantling of sections 2 and 3, sections 4 and 5 have been placed on section 1. Sections n°4 and 5 are identical (same thickness and moisture content); the section 4 is incorporated to provide section 5 with a similar foundation.

PHASE A PHASE B

test section # 3 test section # 5Hydrous state: dry Hydrous state: wetthickness=30cm thickness=30cmtest section # 2 test section # 4Hydrous state: dry Hydrous state: wetthickness=30cm thickness=30cmtest section # 1 test section # 1

Hydrous state: medium Hydrous state: mediumthickness=60cm thickness=60cm

For every section, the compaction is realized with a 28 kg/cm vibratory roller (V2 class).The size of every test section is about 2,5m x 25m.

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CONDITIONS OF USE OF THE MSW SLAGMeasure of average density with the Gammadensimeter (GPV)Measures of density (ρd) in current soils are plotted in a law of the type T(%) = a.log(N)+b

with N= Number of roller passes.The results show the important role of the moisture content, and particularly the difficulty

of compaction in the dry conditions.

d max Standard Proctor

dT ρ ρ

= (%)

80.0

82.0

84.0

86.0

88.0

90.0

92.0

94.0

96.0

98.0

100.0

1 10 100N

ρd/ ρ

d m

ax S

tand

. Pro

ctor

(%)

Section 1 - medium - 0.6m

Section 2 - medium - 0.3m

Section 3 - dry - 0.3m

Section 5 - wet - 0.3m

Evolution of the compaction versus the roller passes N

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CONDITIONS OF USE OF THE MSW SLAG

Measure of the density gradient with the “Gamma Double Probe ”GDS200.

Gradients of density are measured with the «Gamma Double Probe GDS200 » used for the compaction studies. This apparatus allows to measure gradient density up to 2,00m of depth.

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CONDITIONS OF USE OF THE MSW SLAG0

10

20

30

40

50

60

70

80

90

100

110

120

130

1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2ρ d (t/m3)

Dep

th (

cm)

Point 1

Point 2

Point 3

Point 4

0

10

20

30

40

50

60

70

80

90

100

110

120

130

1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2ρ d (t/m3)

Dep

ht (

cm)

Point2'

Point 3'

Point 4'

Point 1'

Measures of ρd= f(z) in 4 points, to the final roller pass number, show low gradients in wet conditions (4 and 5), compared to medium (1) and dry (2 and 3).

Test section 1

Test section 2

Test section 3

Test section 4

Test section 5

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CONDITIONS OF USE OF THE MSW SLAGConditions of compaction for the tested MSW Slag in quality q4 and q3

Embankment quality q4

Moisture Parameters V1 V2 V3 V4 V5

Q/S 0.040 0.070 0.115 0.150 0.185e 0.25 0.35 0.30 0.45 0.30 0.60 0.30 0.75

wet V 2.0 2.0 3.0 2.0 4.0 2.0 5.0 2.0N 6 5 3 4 0.02 4 2 4

Q/L 80 140 345 230 600 300 925 370Q/S 0.025 0.045 0.065 0.09 0.115

e 0.20 0.30 0.30 0.40 0.30 0.55 0.30 0.70medium V 2.0 2.0 2.5 2.0 3.5 2.0 4.5 2.0

N 8 7 5 6 4 6 3 6Q/L 50 90 162.5 130 315 180 517.5 230Q/S 0.02 0.03 0.035

e 0.20 030 0.35dry V 2.0 2.0 2.0

N 10 10 10Q/L 40 60 70

Capping layer quality q3

Moisture Parameters V1 V2 V3 V4 V5Q/S 0.020 0.030 0.040 0.050

e 0.20 0.30 0.30 0.40 0.30 0.50medium V 2.0 2.0 2.5 2.0 3.5 2.0

N 10 10 8 10 0.06 10Q/L 40 60 100 80 175 100

Q/S (m³/m²) : Ratio compacted volume / compacted surface.

e (m) : Compacted thickness

V (km/h) : Travel speed

N (km/h) : Number of passes (1 drum)

Q/L (m³/h per m) : Theoretical output per meter width

V1, V2, …, V5: vibratory roller class

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CONTROL OF COMPACTION BY DYNAMIC PENETROMETER

The aim of these measures is to determine limit values and reference values for the interpretation of controls in MSWS.

Dynamic penetrometer with constant energy PDG1000.

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CONTROL OF COMPACTION BY DYNAMIC PENETROMETER

Average profiles from penetrometerTo make the relationship between settlements per blow ec and compaction values T the average of the 8 profiles of penetration made are calculated by step of 5 cm in depth.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1.0010.00100.00Settlement per blow e c (mm)

Dep

th (m

)

po int 1

po int 2

po int 3

po int 4

po int 5

po int 6

po int 7

po int 8

average

Section test 3

Section test 2

Section test 1

0

0.1

0.2

0.3

0.4

0.5

1.0010.00100.00Settlement per blow ec (mm)

Dep

th (m

)Section test 5

Section test 4

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CONTROL OF COMPACTION BY DYNAMIC PENETROMETER

The final relation for the tested MSW slag is

Log (ec) = a.W + b.T + c.Z

0.00

5.00

10.00

15.00

20.00

25.00

30.00

88.00 90.00 92.00 94.00 96.00 98.00 100.00 102.00 104.00 106.00

Compaction rate T(%)

settl

emen

t per

blo

w (m

m/b

low

)

W=23,8%

W=21,2%

W=19,7%

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CONTROL OF COMPACTION BY DYNAMIC PENETROMETER

After a control, the penetrometer must not overflow on the left of the limit linecorresponding to the moisture class of the material, to conclude to a compliant quality tothe one that would result from the application of conditions of compaction.

0

10

20

30

40

50

60

70

80

90

100

110100

ec (mm/blow)

Dep

th Z

(cm

)

2722

21 17 14 9.5

26.5 19

18 11

19 14 10.513 9 6

0

10

20

30

40

50

60

70

80

90

100

110100

ec (mm/blow)

Dep

th Z

(cm

)

Limit - wet

Reference - wet

Limit - medium

Reference - medium

Limit - dry

Reference - dry

24.5 18 17

13.5

11.5 8

22 15.5

14.5 9

15.5

11.5 8.511

7

5

Limit and reference lines in objective q4 embankment (on the left) and in objective q3 capping layer (on the right) for the tested MSW Slag

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CLASSIFICATION OF MSW SLAG WITH MOISTURE CAPACITY

The whole tests realized had for conclusion to suggest to modify the bounds of moisture classes wet and medium and to place the new borders for the MSW Slag like this:

Limit wet/medium = 1,10xWOMC instead of 1.20xWOMC

Limit wet/very wet = 1,20 x WOMC instead of 1,30 x WOMC

ASSESSMENTS OF SITU BEARING CAPACITYMeasurements of modulus made with static plate Ø 600 mm or with the Dynaplaque 2 have

been done on the whole of the test sections. The values are around 20 MPa in the wet moisture, and near of 50 MPa to the medium and dry moisture conditions, however without passing this value.

The use of the MSW Slag confirms the observations made during the laboratory tests on the atypical behaviour of the material. Whereas the sensivity with water exists (rubber cushion when wet), the MSW Slag has a greatly draining behaviour: it changes on one day from a wet, to a medium state near the optimum moisture content.

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CONCLUSIONSThe experiment defines the possibilities to use the tested MSW Slag without

treatment in embankments and in capping layers.

The marginal character of this material is confirmed: in one hand, the conditions of compaction are close to a natural soil between a very silty and an argilous ones but, in other hand, its porosity, its important friction, its strong evolution under stresses, and its draining properties do not permit to deduce its mechanical behaviour from the natural soils above. For these reasons, specific tables of compaction conditions have been determined.

These experiment are going on with similar tests, realized on another nature of MSW Slag from Paris area, to widen the conclusions