1. Siteworks & Earthworks

Acronyms

• AASHTO: American Association of State Highway and Transportation Officials
• ANSI: American National Standards Institute
• ASTM: American Society for Testing and Materials
• USCS: Unified Soil Classificatory System

AASHTO Soil Classification System

• Classifies inorganic soils based on drainage and bearing capacity.
• Particle sizes:
  • Boulders: above 75mm
  • Gravel: 75mm to No. 10 sieve
  • Coarse Sand: No. 10 to No. 40 sieve
  • Fine Sand: No. 40 to No. 200 sieve
  • Silt-Clay Particles: passing No. 200 sieve

Atterberg Limits

• Tests performed on soils passing the No. 40 sieve.
  • Liquid Limit (LL): moisture content at which soil transitions from liquid to plastic state.
  • Plastic Limit (PL): water content at which silt or clay crumbles when rolled into a 3.2 mm diameter tread.
  • Plastic Index (PI): range of water content where sediment behaves plastically (LL - PL).

Fill Materials

• Soil, crushed stone, and sand used to raise existing grades.
• Classified under the USCS:
  • GW, GM, GP: Gravels with > 50% retained on No. 200 sieve and 50% of coarse fraction retained on No. 40 sieve
  • SW, SM: Sands with 50% retained on No. 200 sieve and 50% or more of coarse fraction passing No. 40 sieve

No. 40 Sieve

• Granular Fill or Filters: soil materials conforming to General Fill requirements, ASTM C33, size 67, with a sand equivalent of not less than 50%.
• Borrow Fill: soil suitable as fill or sub-grade, selected laboratory-approved pit-run gravel, disintegrated granite, sand, shale, cinders, with not more than 35% fraction passing the No. 200 sieve.
• Base Course Materials: hard durable fragments of stone and a filler of sand, free from vegetable matter and clay, complying with AASHTO METHOD T-11 and T-26 Grading Requirements.

Riprap

• Constructed layer of stone used to prevent erosion, scouring, or sloughing.
• Ranges in diameter from 50 mm (2 inches) to 1148 mm (42 inches).

Gabion Systems

• Stone-filled wire baskets used for soil stabilization and erosion prevention.
• Wire fabric containers, uniformly partitioned, of variable size, interconnected with baskets.

Geosynthetics

• Synthetic components made for use with or within earth materials.
• Categorized into:
  • Geotextiles: woven or nonwoven fabric made from polymeric materials.
  • Geonets: continuous extrusion of polymeric ribs creating void space for in-plane flow.
  • Geomembranes: continuous, impermeable polymeric sheets.
  • Geocells: three-dimensional prefabricated polymeric systems ranging from 100mm to 200mm high.
  • Geocomposites: combination of geosynthetic components.

Geotextiles

• Most common geosynthetic.
• General uses:
  • Reinforcement: increases design strength and reduces sub-base and base course deterioration.
  • Separation: prevents migration of dissimilar materials.
  • Filtration: prevents movement of fine particles from the soil through seepage.

Filtration Categories

• Subsurface Drainage: employed in subsurface drainage applications, such as filters around underdrains or edge drains.

Erosion Control

• Employed to protect cut slopes or drainage features.
• Serve a secondary function of separation when used with stone lining or rip rap.

Sediment Control Geotextiles

• Exclusively used for silt fence applications.
• Serve as filters with a different mechanism than subsurface drainage or erosion control.

Membranes

• Ethylene propylene diene monomer (EPDM) is commonly used for membrane roofing.
• Uses include lining for ponds, lagoons, landfills, canals, reservoirs, roads, and waterproofing.

Geocomposites

• Usually a sheet or edge drain with a prefabricated core bonded to a geotextile filter.
• The core provides void space for water flow.

Geomembranes

• Continuous, impermeable polymeric sheets.
• Manufactured from high-density polyethylene (HDPE) and polyvinyl chloride (PVC).

Geonets

• Continuous extrusion of polymeric ribs creating void space for in-plane flow.
• Available with or without bonded geotextile filters.

Geocells

• Three-dimensional, prefabricated polymeric systems ranging from 100mm to 200mm high.
• Used for stabilization and protection of steep slope surfaces and channel linings.

Slope-Erosion Protection Materials

• Used for temporary and permanent erosion protection.
• Temporary materials:
  • Open mesh polymeric systems.
  • Biodegradable mesh system (e.g., coco coir, jute).
  • Combination of polymeric and biodegradable mesh.

Physical Barriers

Termite Resistant Sand

• Layer of sand preventing termites from moving through or building tunnels.
• More uniform and effective than chemical barriers.

Termite Mesh

• Fine steel mesh that prevents termites from passing through.
• Used in slab construction, wrapping pipes, and other access areas.

Home Construction

• Homes are sometimes designed on high concrete pillars in high-risk areas to separate the home from termites.

Chemical Barriers

• Objective: Create a continuous barrier between soil and structure to control termites.
• Pre-construction barriers: Applied during construction to soil and foundations, or use of termite-resistant building products.
• Vertical barriers: Rodding or trenching around foundation bases, plumbing, utility entrances, and expansion joints.
• Horizontal barriers: Applying 1 gallon of termiticide per 10 square feet, typically by coarse spray at low pressure.

Slab Treatment

• Drilling through slab floor and injecting termiticides into the soil at regular intervals.

Basements and Crawl Spaces

• Trenches dug around foundation, with termiticide applied to trenches and soil within the crawl space/basement.

Colony Elimination (Bait) System

• Objective: Eliminate entire worker population and colony using slow-acting insect growth regulator (IGR) - hexaflumuron - in baits.

Pavements

• Wearing surface for pedestrian and vehicular traffic.
• Thickness and construction factors:
  • Intensity and type of traffic loads.
  • Bearing capacity and permeability of the sub-grade.

Pavement Types

• Rigid: Reinforced concrete slabs or paving units mortared over a concrete slab. Loads are distributed internally.
• Flexible: Made of concrete, brick, or stone; flexes under pressure rather than cracking.

Turf Pavements

• Unit pavers with spacing for grass or ground covers over a topsoil mix.
• Used for driveways, patios, sidewalks, porch floors, etc.

Paving Patterns

• Variety of shapes creating different patterns.
• Absorb heating and movement.

Roads and Parking

• Materials for horizontal structures.

Subgrade and Base Course Materials

Subgrade

• Borrow Material: soil suitable as fill or sub-grade
• Base Course Material: hard durable fragments of stone and a filler of sand

Choker Aggregate

• A filter layer of finer material over a coarse road base material, providing a stable foundation for pavement.

Pervious Asphalt Pavement

• Choker Course, uniformly graded clean crushed stone, 40% Voids

Surface Paving Material

Concrete

• Described in a separate Module.

Bituminous Surfacing

• HOT MIX ASPHALT or ASPHALTIC CONCRETE: dark brown to black cementitious material composed of bitumens.
• COLD MIX ASPHALT OR ASPHALTIC CONCRETE: asphaltic concrete prepared with a relatively light and slow-curing asphalt, placed over a prepared surface without heat.
• ASPHALTIC MACADAM: formed by grading and compacting layers of crushed-stone or gravel, then binding the top layer with asphalt.
• ASPHALT OVERLAY: one or more courses of asphalt placed on existing pavement.
• MACADAM ROAD: type of road construction using single sized aggregate layers of stone with a coating of binder.

Module 1 - Materials of Construction - Building Technology (Atlas)