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Flashcards in Soils and Aggregates Deck (52)
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1

What are the Soil properties that help determine the spatial allocation of land-uses, the design and construction of structures, and the selection and installation of plant materials

Physical and Chemical Properties

2

Aggregates

Crushed rock or gravel

3

What are the 3 characteristics that define a Soil Profile?

textures, mineral contents, and chemical makeup

4

What are the soil Horizons

O, A, B, C, D

5

O/A Horizon (Organic Horizon) (2"-2')

Surface Layer

6

B Horizon (Subsoil) (4"-8')

Horizons of Maximum Accumulation
Clay

7

C Horizon (Substratum) (Parent Material)

Weathered parent material

8

D Horizon (Underlying Stratum)

BedRock

9

Soil Particle Sizes

(1) Clay (2) Silt (3)Sand (4) Gravel (5)Cobbles

10

Residual Soils

Remains above its parent rock

11

Transported Soils

Materials that have been moved from another place by glaciation, wind, water, or gravity

12

What was the USDA Classification System developed for?

Agriculture

13

USDA Classification System

Describes the relative proportion of clay, silt, and sand particles

14

What are the 11 Basic Soil Orders of the USDA Classification System based on?

Climate, Parent Material, Vegetation

15

What was the AASHTO Classification System developed for?

Devised for highway construction suitability
Engineering Properties of Soils

16

What are the 2 major soil groups in the AASHTO Classification System?

Granular Materials & Silt-Clay Materials

17

What were the Unified Systems developed for?

Devised for highway engineering

18

What are the 3 soil categories in the Unified Systems?

Coarse-grained Soils, Fine-grained Soils, Organic Soils

19

Order Coarse-grained, Fine-grained, Organic Soils from Excellent to Not Suitable, for use as Foundation Material.

Coarse-Grained: Excellent to Fair
Fine-Grained: Fair to Poor
Organic Soil: Not Suitable

20

Cumulose Soil

Organic

21

What are the Physical Properties of Soil?

Texture, Color, Density, Capillarity, Permeability, Shrinkage and Swell, Cohesion

22

How to obtain information about soil texture?

Soil Survey Report

23

What is Soil Density?

The Total Volume of Solids and Voids in Soil

24

Capillarity

Upward movement of moisture or water above the water table as a function of fine-textured soil

25

What are Clay & Silts and Coarse-textured soils capillary action?

Clay & Silts have High Capillary action
Coarse-textured soils have a lower capillary action

26

Permeability

The ability of soil to transmit water downward due to gravity Pore space

27

Shrinkage and Swell

Buildup and release of capillary tensile stresses within soil due to water

28

Cohesion

The ability of a soil sample to bind together when moderately dry

29

Elasticity

The ability of soil to return to its original shape after being deformed by a load. Compatibility of a soil

30

Plasticity

Refers to the ability of soil to be deformed under pressure without cracking or crumbling and to maintain a deformed shape after pressure is released

31

Liquid Limit

The liquid limit refers to the moisture content at which soil passes from a liquid to a plastic state as moisture is removed

32

Plastic Limit

Plastic Limit refers to the moisture content at which soil passes from a plastic to a semisolid state as water is removed

33

Frost Susceptibility

The relative tendency of some soil to swell due to frost when the moisture in the soil freezes

34

Are Fine-Grained or Coarse-Grained soils more susceptible to frost-action?

Fine-grained are more susceptible to freeze than coarse-grained

35

Compressibility and Compaction

Compact soil to increase its ability to support the weight

36

Bearing Strength

The ability of a soil to support a load without failure

37

What 3 factors affect Bearing Strength?

Water Content, Rate and time of loading, Confining pressure

38

What are the 3 components of Drainage?

Runoff, Internal Drainage, Permeability or porosity

39

Erodibility

The extent to which a soil mass can withstand the forces of wind or water erosion

40

Spatial Variability

Most urban sites consist of more than one soil type but are seldom mapped

41

Available Moisture and Adequate Drainage

Ideal Ratio Airspace to Water 1:1

42

Soil pH

Acidity or alkalinity of a Soil

43

What are the soil pH levels for acidic soil? For alkaline soil?

Acid is 0-6.5
Neutral is 6.6 - 7.3
Alkaline is 7.4 - highest

44

Colloidal Content

Refers to the number of clay particles in a soil sample

45

Depth

Depth to Bedrock, to water table or to unweathered parent materials

46

At what depth should plants be installed?

Between 18" - 36"

47

Issues with Urban Soils

Compaction, Increased runoff, Oxygen deficient environment, severely inhibited root growth, Increased thermal conductivity, Limited nutrient availability

48

Natural Granular Materials

Sand, gravel, crushed stone

49

Manufactured Granular Materials

Slag, vermiculite, pumice, and crushed brick

50

Relevant Properties of Aggregates

Cleanliness, Soundness, Gradation

51

Common Applications of Aggregates

Foundations, Finished Surfaces, Vehicular Roads and Parking Areas

52

Soil is made up of

minerals, water,air