Term
| Push-Loaded Single-Powered Scraper |
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Definition
(Scraper)
High travel speed
Uneconomical: haul grades >5%, return grades >12% |
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Term
| Push-Loaded Tandem-Powered Scraper |
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Definition
(Scraper)
Overcome high RR and/or steep grades (adverse or poor footing)
Owning and operating cost, 25% higher |
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Term
| Self-loading Push-pull Tandem Scraper |
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Definition
(Scraper)
Hook, cushioned-push block and bail
Assist one another: lead scraper, trailing scraper
More slippage form the four-wheel-drive: increased tire wear in rock or abrasive materials |
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Term
| Self-loading Elevating Scraper |
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Definition
(Scraper)
Self-contained loading and hauling
Good for short hauls, small quantity situations
Cannot handle rock |
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Term
| Self-Loading Auger Scraper |
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Definition
(Scraper)
Rotating *** lifts material off scraper cutting edge and carries it to the top
Self-load in difficult conditions: laminated rock, frozen, or granular materials
Most costly to own and operate |
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Term
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Definition
(Scraper Component)
Loading and carrying
Lowered for loading and raised during travel |
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Term
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Definition
(Scraper Component)
Front wall of the bowl
Raised during the loading and dumping |
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Term
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Definition
(Scraper Component)
Rear vertical wall of the bowl
Moves forward to provide position discharge |
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Term
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Definition
(Scraper)
Job size: volume of material, maneuver room
Job conditions: grades, rolling resistance, material type
Scraper configuration
Cost: hourly |
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Term
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Definition
1.Fixed: spot, load, maneuver, dump
2.Variable: haul and return
3.Loading
4.Haul travel
5.Dumping and spreading
6.Turning
7.Return travel
8.Turning and positioning to pick up another load |
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Term
| Estimating Scraper Production |
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Definition
Production Cycle
Cycle Time |
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Term
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Definition
(Compaction)
One, two or four steel-padded wheels
Mix and compact
All soils but pure sand |
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Term
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Definition
Self-propelled, relatively high speed
Passes over 8-12 in lift
Not compact 2-3 in lift |
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Term
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Definition
(Compaction)
Cylindrical pads, less than 10 in in length
o Hollow steel drum
o As a towed assembly
Can compact fine-grained
Not for cohesion-less granular |
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Term
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Definition
Drum rotates pads
pads penetrate and compact the lift
Pads kick up or fluff the material |
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Term
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Definition
Aerate soil as it compacts
ok above acceptable moisture content |
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Term
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Definition
6-10 passes over an 8in clay lift
Working speed: approx. 4 mph
Not ok for 2-8 in lift |
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Term
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Definition
(Compaction)
Drum made of heavy steel mesh
Best for clean gravels and sands
Breaks up lumps of cohesive soil
Crushing and compacting soft rock |
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Term
| Rubber-Tired or Pneumatic Roller |
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Definition
(Compaction)
Asphalt, chip seals, recycling pavement, base and subbase
o Worst on clean sand and gravels
Front and rear tire paths overlap
Area of contact dep on tire air pressure |
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Term
| Steel Wheel or Smooth Drum |
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Definition
(Compaction)
Granular bases, asphaltic bases, asphalt pavements |
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Term
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Definition
(Compaction)
Non-cohesive materials and asphalt pavement
Vary frequency and amplitude |
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Term
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Definition
(Compaction)
In confined area
High impact force (high amplitude)
Cohesive and semi-cohesive soils |
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