Soils and Aggregates

Question 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

Answer 1

Physical and Chemical Properties

Question 2

Aggregates

Answer 2

Crushed rock or gravel

Question 3

What are the 3 characteristics that define a Soil Profile?

Answer 3

textures, mineral contents, and chemical makeup

Question 4

What are the soil Horizons

Answer 4

O, A, B, C, D

Question 5

O/A Horizon (Organic Horizon) (2”-2’)

Answer 5

Surface Layer

Question 6

B Horizon (Subsoil) (4”-8’)

Answer 6

Horizons of Maximum Accumulation

Clay

Question 7

C Horizon (Substratum) (Parent Material)

Answer 7

Weathered parent material

Question 8

D Horizon (Underlying Stratum)

Answer 8

BedRock

Question 9

Soil Particle Sizes

Answer 9

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

Question 10

Residual Soils

Answer 10

Remains above its parent rock

Question 11

Transported Soils

Answer 11

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

Question 12

What was the USDA Classification System developed for?

Answer 12

Agriculture

Question 13

USDA Classification System

Answer 13

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

Question 14

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

Answer 14

Climate, Parent Material, Vegetation

Question 15

What was the AASHTO Classification System developed for?

Answer 15

Devised for highway construction suitability

Engineering Properties of Soils

Question 16

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

Answer 16

Granular Materials & Silt-Clay Materials

Question 17

What were the Unified Systems developed for?

Answer 17

Devised for highway engineering

Question 18

What are the 3 soil categories in the Unified Systems?

Answer 18

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

Question 19

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

Answer 19

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

Question 20

Cumulose Soil

Answer 20

Organic

Question 21

What are the Physical Properties of Soil?

Answer 21

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

Question 22

How to obtain information about soil texture?

Answer 22

Soil Survey Report

Question 23

What is Soil Density?

Answer 23

The Total Volume of Solids and Voids in Soil

Question 24

Capillarity

Answer 24

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

Question 25

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

Answer 25

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

Question 26

Permeability

Answer 26

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

Question 27

Shrinkage and Swell

Answer 27

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

Question 28

Cohesion

Answer 28

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

Question 29

Elasticity

Answer 29

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

Question 30

Plasticity

Answer 30

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

Question 31

Liquid Limit

Answer 31

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

Question 32

Plastic Limit

Answer 32

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

Question 33

Frost Susceptibility

Answer 33

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

Question 34

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

Answer 34

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

Question 35

Compressibility and Compaction

Answer 35

Compact soil to increase its ability to support the weight

Question 36

Bearing Strength

Answer 36

The ability of a soil to support a load without failure

Question 37

What 3 factors affect Bearing Strength?

Answer 37

Water Content, Rate and time of loading, Confining pressure

Question 38

What are the 3 components of Drainage?

Answer 38

Runoff, Internal Drainage, Permeability or porosity

Question 39

Erodibility

Answer 39

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

Question 40

Spatial Variability

Answer 40

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

Question 41

Available Moisture and Adequate Drainage

Answer 41

Ideal Ratio Airspace to Water 1:1

Question 42

Soil pH

Answer 42

Acidity or alkalinity of a Soil

Question 43

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

Answer 43

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

Question 44

Colloidal Content

Answer 44

Refers to the number of clay particles in a soil sample

Question 45

Depth

Answer 45

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

Question 46

At what depth should plants be installed?

Answer 46

Between 18" - 36"

Question 47

Issues with Urban Soils

Answer 47

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

Question 48

Natural Granular Materials

Answer 48

Sand, gravel, crushed stone

Question 49

Manufactured Granular Materials

Answer 49

Slag, vermiculite, pumice, and crushed brick

Question 50

Relevant Properties of Aggregates

Answer 50

Cleanliness, Soundness, Gradation

Question 51

Common Applications of Aggregates

Answer 51

Foundations, Finished Surfaces, Vehicular Roads and Parking Areas

Question 52

Soil is made up of

Answer 52

minerals, water,air