Reuse Of Petroleumcontaminated Soils In Concrete Production

An experimental investigation designed to evaluate the effectiveness of using petroleum-contaminated soils (PCS) as fine aggregate replacement in concrete was conducted at Stevens Institute of Technology. The details of the experimental program and the resulting findings are

Table 6 Research on Stabilization using Pozzolanic Binders

Binder

Waste type

Waste description

Organization

Fly ash, lime

Class C ash, lime, and cement mixtures with Class F ash Fly ash, lime

Portland cement, fly ash, calcium sulfate dihy-drate, lime, recycled rubber, asphaltene, adsorbent material Class C fly ash, hydraulic blast furnace slag Portland cement, Class C

and Class F fly ash Class C fly ash

Fly ash, portland cement

Fly ash, cement, lime, hemihydrated calcium sulfate, dehydrated calcium sulfate Type I cement with Class F

fly ash Portland cement, Class C

fly ash T^pe 2 portland cement

Class C fly ash Class C fly ash, lime

Organic Acid hydrocarbon sludge, spent clay

Organic Solvent extraction raffinate

Organic Methanol, xylene, benzene, adipic acid, oil and grease Organic Organic sludges

Inorganic Radioactive waste alkaline salt solution Inorganic Radioactive soluble salts waste

Inorganic Mo processing waste, Zn refining sludge, electroplating sludge Inorganic Zinc nitrate, cadmium ni trate, mercury chloride, mercury nitrate solutions Inorganic Neutralized sludge from titanium processing

Inorganic Iron, steel

Inorganic Electroplating sludge

Inorganic Synthetic metal hydroxide sludges

Inorganic Water-based drilling muds

Organic and Garbage and chemical incin-inorganic erator waste, gasification ash and slag, sewer sludge, kiln waste, gypsum, ash from Lo-nox burners, fluidized-bcd ashes

Drexel Univ. ORNL/DOE

Corps of Engineers

Velsicol Chemical Corp.

DOE Pennsylvania State

Univ. American

Resources Corp.

Oxford Univ. Imperial College

State Univ. of New York

Pennsylvania State

Univ. Univ. of Missouri

Univ. of New Hampshire Univ. of Oklahoma Aardelite USA

discussed by Ezeldin [5-7]. In this section a general description of the experimental program and highlights of results are presented.

Five PCS types with different levels of heating oil and gasoline contamination were investigated. Three PCS/sand replacement ratios were incorporated. Setting times, strength, durability, and leachability of benzene to water were evaluated. Type III portland cement meeting ASTM C-150 standard specifications was used during the entire experimental program. Fine

Table 7 Interaction of Solidification/Stabilization Binders and Organic Chemical Groups

Chemical group

Bitumen

Acrylamide

Alcohols and glycols

Durability: no significant effect

Durability: decrease

Aldehydes and ketones

Durability: decrease (destructive

Durability: no significant effect

action occurs over a long time

period)

Aldehydes only—Set time and

durability: no significant effect

Aliphatic and aromatic

Durability: decrease (destructive

Durability: no significant effect

hydrocarbons

action occurs over a long time

period)

Amides and Amines

D/U

D/U

Chlorinated hydrocarbons

D/U

Durability: no significant effect

Ethers and epoxides

D/U

Durability: no significant effect

Heterocyclic

D/U

Durability: no significant effect

Nitriles

D/U

D/U

Organic acids and acid

Durability: no significant effect

Set time: increase (lengthen or pre

chlorides

vent from setting)

Durability: no significant effect

Organometallics

D/U

D/U

Phenols

Durability: decrease (destructive

D/U

action occurs over a long time

period)

Organic esters

D/U

D/U

D/U = data unavailable. Source: Spooner et al. [3].

D/U = data unavailable. Source: Spooner et al. [3].

aggregate was a natural sand, and coarse aggregate consisted of 3/8-in. crushed stone. The soil classification, moisture content, contaminant type, and contamination concentration are shown in Table 10. Soils were sieved through a No. 4 sieve before use to discard any debris or large unwanted particles.

A concrete control mixture with no PCS was used as reference and had a compressive strength of 6000 psi after 7 days. For each soil type, three mixtures were obtained by replacing sand with PCS (PCS/sand ratio of 10%, 20%, and 40% by weight). Table 11 shows the mixture proportions and designations. After mixing, the following specimens were cast: 3 x 6 in. and 4X8 in. cylinders for compression tests, 4 X 4 X 14 in. prisms for flexural tests, 2 x 2 x 10 in. prisms for durability tests, and 2 x 2 x 2 in. cubes for leachability tests. All concrete specimens were left at room temperature for 24 hr and then removed from their molds. They were then immersed in water until testing, with the exception of the leachability test specimens, which were left uncovered at room temperature.

The 3 x 6 in. compression cylinders were tested in duplicate at an early age (2 days; see Table 12). The 4 X 8 in. compression cylinders were tested in duplicate at a later age (7 days; see Table 12). Tests were conducted in accordance with ASTM procedure C-39. The 4 X 4 x 14 in. prisms were tested after 7 days according to ASTM C-78 as indicated in Table 12. The durability tests consisted of two parts: freeze-thaw testing and wet-dry testing. The wet-dry testing was performed in accordance with ASTM D-559, while the freeze-thaw testing was performed according to ASTM D-560. The leachability test were performed in duplicate on monolithic 2 x 2 X 2 in. concrete cubes obtained using mixture C3 for each of the five soil types (see Table 11).

Table 8 Interaction of Solidification/Stabilization Binders and Organic Chemical Groups

Chemical group

Phenolic

Urethane

Urea-formaldehyde

Epoxy

Polyester

Alcohols and glycols D/U

Aldehydes and ketones

Aliphatic and aromatic hydrocarbons

Amides and amines

Chlorinated hydrocarbons

Set time: decrease Durability: no significant effect

Durability: decrease (destructive action occurs over a long time period) Low molecular weight polymers only D/U

Durability: decrease (destructive action occurs over a long time period)

Ethers and epoxides D/U

Set time: decrease Durability: no significant effect Durability: decrease (destructive action occurs over a long time period) Durability: no significant effect

Durability: decrease (destructive action begins within a short time period) Durability: no significant effect

Durability: no significant effect

Set time: increase Durability: no significant effect

Set time: increase (lengthen or prevent from setting) Durability: no significant effect Durability: decrease (destructive action occurs over a long time period)

Durability: no significant effect

Durability: decrease (destructive action occurs over a long time period)

Durability: decrease (destructive action occurs over a long time period)

Durability: no significant effect

Durability: decrease (destructive action occurs over a long time period)

Durability: decrease (destructive action occurs over a long time period)

Chemical group

Phenolic

Urethane

Urea-formaldehyde

Epoxy

Polyester

Heterocyclics

D/U

D/U

D/U

D/U

D/U

Nitriles

D/U

D/U

D/U

D/U

D/U

Organic acids and

D/U

Set time: increase

Set time: no significant

Durability: decrease

Durability: decrease

acid chlorides

(lengthen or prevent

effect

(destructive action

(destructive action

from setting)

Durability: no signifi

occurs over a long

occurs over a long

Durability: no signifi

cant effect

time period)

time period)

cant effect

Organometallics

D/U

D/U

D/U

D/U

D/U

Phenols

Set time: increase (lengthen or prevent from setting) Durability: no significant effect

Durability: decrease (destructive action begins within a short time period)

D/U

D/U

D/U

Organic esters

D/U

D/U

D/U

D/U

D/U

D/U = data unavailable. Source: Spooner et al. [3],

D/U = data unavailable. Source: Spooner et al. [3],

Table 9 Interaction of Solidification/Stabilization Binders and Inorganic Chemical Groups

Chemical Group

Bitumen

Silicate

Acrylamide

Phenolic

Urethane

Urea-formaldehyde

Epoxy

Polyester

Heavy metal salts and complexes

Inorganic acids

Durability: decrease (destructive action occurs over a long time period) Durability: no significant effect

Nonoxidizing, except concentrated acids

Set time: decrease

Set time:

decrease Durability: no significant effect

Set time: increase (lengthen or prevent from setting)

Set time: increase (lengthen or prevent from setting)

Durability: decrease (destructive action begins with in a short time period)

Durability: no Set time:

significant effect. Nonoxidizing increase (lengthen 01 prevent from setting) Durability: decrease (destructive action begins within a short time period)

Durability: no significant effect

Set time: no Durability: no Durability: no significant effect Durability: decrease (destructive action occurs over a long time period)

significant effect. Nonoxidizing significant effect. Nonoxidizing, except NF

Chemical

Urea-

Group

Bitumen

Silicate

Acrylamide

Phenolic

Urethane

formaldehyde

Epoxy

Polyester

Inorganic bases

Durability: no

Set time:

Set time:

Durability:

Durability:

Set time:

Durability: no

Durability:

significant

increase

decrease

decrease

decrease

increase

significant

decrease

effect

(lengthen or

Durability:

(destructive

(destruction

(lengthen or

effect

(destructive

prevent from

decrease

action occurs

action occurs

prevent from

action occurs

setting)

(destructive

over a long

over a long

setting)

over a long

Durability:

action occurs

time period)

time period)

Durability:

time period)

decrease

over a long

decrease

(destructive

time period)

(destruction

action begins

action begins

with in a

within a short

short time

time period)

period)

Inorganic salts

Durability:

Set time:

Set time:

Set time:

Durability:

Durability: no

Durability: no

Durability: no

decrease

decrease

decrease

decrease

decrease

significant

significant

significant

(destructive

Durability:

Durability: no

(destruction

effect

effect

effect

action occurs

decrease

significant

action occurs

over a long

(destructive

effect

over a long

time period)

action occurs

Bleaches—

time period)

over a long

Set time:

time period)

decrease

Durability:

decrease

(destructive

action occurs

over a long

time period)

D/U = data unavailable. Source: Spooner et al. [3J.

D/U = data unavailable. Source: Spooner et al. [3J.

Table 10 Soil Description

Soil

Classification

Moisture content (%)

Type of contaminant

Concentration

1

Well-graded sand

7.3

Heating oil

0.11% by weight

2

Clay-silty

14.3

Heating oil

0.12% by weight

3

Silty sand

24.7

Heating oil

0.66% by weight

4

Poorly graded sand

14.4

Gasoline

25 ppm

5

Silty clay

19.6

Gasoline

1500 ppm

The initial and final setting times of concrete are commonly defined by the ASTM C-403 test method. Setting times are determined from the rate of solidification curve. The solidification curve of the control mixture is shown in Figure 1. The recorded initial and final setting times were about 1.5 and 6 hr, respectively. Figure 2 indicates the effect of introducing PCS (soil Type 1) on the initial and final setting times of concrete. The initial setting time seems to increase with the increase of PCS/sand replacement ratio. The final setting time is found to be less affected by the increase in the PCS/sand replacement ratio. For instance, at a PCS/sand replacement ratio of 40%, the initial setting time increases by about 30% compared to the control mix, while the final setting time increases by only 20%. A similar trend is observed for all five soil types included in this investigation. During this experimental program, all concrete mixtures reached their final setting time well before the specimens were removed from the molds, that is, in less than 24 hr (usually within 9 hr). The effect of contaminant concentration on setting time can be seen in Figure 3. When comparing the setting time of soil 1 (0.11% contaminant concentration) to soil 3 (0.66% contaminant concentration), it is found that both the initial and final setting times are consistently greater for the soil with higher contaminant concentration. These results indicate that the inclusion of PCS and the contaminant concentration affect the setting time of concrete. However, for the soil types included in this inves-

Table 11 Mixture Proportions

Mix

Cement

Sand/

PCS/

PCS/

Water/

Soil type

design

(lb/yd3)

cement"

cement"

sand

cement"

Control

C

800

1.52

0.50

1

ICI

800

1.37

0.15

10%

0.45

1C2

800

1.21

0.31

20%

0.45

1C3

800

0.91

0.61

40%

0.45

2

2C1

800

1.37

0.15

10%

0.56

2C2

800

1.21

0.31

20%

0.56

2C3

800

0.91

0.61

40%

0.56

3

3C1

800

1.37

0.15

10%

0.47

3C2

800

1.21

0.31

20%

0.47

3C3

800

0.91

0.61

40%

0.47

4

4C1

800

1.37

0.15

10%

0.48

4C2

800

1.21

0.31

20%

0.48

4C3

800

0.91

0.61

40%

0.48

5

5C1

800

1.37

0.15

10%

0.49

5C2

800

1.21

0.31

20%

0.49

5C3

800

0.91

0.61

40%

0.49

"Ratio by weight.

Note: Ratio of coarse aggregate to cement (by weight) = 1.52. Water/binder ratio was adjusted to maintain slump value at 6 + 1-in. slump.

"Ratio by weight.

Note: Ratio of coarse aggregate to cement (by weight) = 1.52. Water/binder ratio was adjusted to maintain slump value at 6 + 1-in. slump.

Table 12 Experimental Strength Results

Compressive

Table 12 Experimental Strength Results

Compressive

Mix desig.

strength (psi) 2 days 7 days

Flexural strength (psi), 7 days

Unit weight (lb/ft3)

C

4950

6160

975

151.6

ICI

4950

5569

975

152.5

1C2

4950

5171

956

148.4

1C3

4450

5370

843

146.5

2C1

3258

5728

750

143.6

2C2

2691

5171

731

141.6

2C3

2124

3262

656

137.4

3C1

3536

4379

693

144.3

3C2

2404

3941

675

142.6

3C3

2263

3503

487

138.4

4C1

3395

4658

881

148.9

4C2

3395

4419

788

149.3

4C3

3253

4140

788

154.3

5C1

2688

4928

693

151.6

5C2

2826

4805

656

149.9

5C3

2826

3819

637

148.6

tigation and for the contaminant concentrations used, this effect is not major; with a 0.66% contaminant concentration and a PCS/sand replacement ratio of 40%, the initial and final setting times recorded were only 50% and 30% higher, respectively.

The compressive and flexural results for all five soils are given in Table 12. Figures 4-8 indicate that, irrespective of the soil type, concrete with a higher PCS/sand replacement ratio develops lower compressive and flexural strengths at both early and late stages. The presence of contaminants seems to interfere with the water-cement binding reactions, delaying or preventing the full hydration of the cement particles. The increase of PCS content (increase of PCS/sand replacement ratio) yields to the presence of more petroleum contaminants, which a, u a i

TIME, HOURS

Figure 1 Solidification curve of control mixture.

TIME, HOURS

Figure 1 Solidification curve of control mixture.

Figure 2 Effect of PCS replacement percentage on setting time.

PCS replacement percentage

Figure 2 Effect of PCS replacement percentage on setting time.

separate the cement particles from water. Hence, for the same total content of cement, less is actually available to react with water to produce the hardened binder. This results in the concrete being weaker than the control. The strength reduction at each PCS/sand replacement ratio level depends on contaminant concentration, contaminant type, and soil type. The increase in contaminant concentration has an adverse effect on the concrete strength. When comparing the strength results of concrete containing soil 1 (sandy soil with 0.11% oil contamination) and soil 3 (sandy soil containing 0.66% oil contamination), the results indicate the following. While the presence of soil 1 with a PCS/sand replacement ratio of 40% reduces the concrete compressive strength by 10% after 2 days and 13% after 7 days, the presence of soil 3 with the same PCS/ sand replacement ratio yields concrete 54% weaker than the control after 2 days and 43% weaker after 7 days. A strength comparison for concrete containing soil 1 (sandy with 0.11% oil contamination) and concrete containing soil 4 (sandy with 0.003% gasoline contamination) reflects the effect of contaminant type on strength; sandy soil contaminated with gasoline produces concrete of lower strength than concrete containing a higher concentration of heating oil.

jij PCS replacement percentage

■i INITIAL SET TIME(SI) ^ INITIAL SET TIMEIS3)

jij PCS replacement percentage

■i INITIAL SET TIME(SI) ^ INITIAL SET TIMEIS3)

Figure 3 Effect of contamination concentration on setting times.

COMPRESSION

FLEXURAL

S

1200

T

R

1000

E

N

800

G

T

600

H

,

400

P

200

S 1

0

0 0

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