Introduction to Compaction - PDF Free Download

Overview - Compaction Principles Soil Compaction Asphalt Compaction Compaction Forces Factors Affecting Compaction Equipment Common Designs Applications Selling Tips Measuring Compaction Troubleshooting 2

Compaction: Definition: The process of mechanically increasing the density of a material. 3 Purpose: Materials are made more stable and stronger Compaction compresses the materials thereby removing voids, reducing a specific volume of material into one of a lesser volume. Denser, or more compacted materials are able to support heavier loads without becoming unstable and collapsing.

There is 2 basic types of compaction: Soil Compaction Asphalt Compaction 4 A variety of equipment can be used for either or both including: Rammers Used only for soil compaction Vibratory Plates One-direction - used for either soil or asphalt compaction Two-direction - used primarily for soil Walk-behind and Ride-on Rollers Double drum rollers can be used for either soil or asphalt compaction Sheepfoot/padfoot rollers or rollers with tread/traction tires are only used on soil

Vibrating Plate equipment can be used for either Asphalt or Soil Used for either soil or asphalt compaction depending how the units are manufactured. Factors Impact force 3000-3500 lbs better for asphalt 5 4000-5100 lbs better for soil Water tank Needed for asphalt application Purpose - acts as lubricant between asphalt and bottom of plate.

Soil Type Five accepted types of soil classifications: clay, silt, fine sand, coarse sand, and gravel 6 Organized into three groups: Granular sands and gravel; Cohesive silt and clay; Mixed which is a mixture of granular and cohesive. Plates are used for granular and mixed soils. When using a plate on mixed soil it must only contain a small amount of clay content.

Soil Types Cohesive Soils Bonding is by Molecular Attraction Granular Soils Bonding is by Frictional Forces Mixed Soils Critical Percentage is 35% Cohesive Soil. When using plate compactors on mixed soil, far less % of clay is desirable. Soil Type is determined by the size of the particles. Clay and silt are very fine grains. Sand and gravel are larger particles. 7

Soil Types Mixed Cohesive Soils When wet, the material feels plastic and sticky and can be rolled or shaped into a ball. Granular Cohesive 8 Granular Soils When wet, granular soils such as sand can be formed however, they will crumble readily. Mixed Soils When wet, this soil has little or no plasticity. When dry, the soil crumbles and flakes readily.

Soil Types and Compaction Force Cohesive Soils Cohesive soils tend to naturally stick together forming lumps like modeling clay, creating air pockets. A strong (shearing type) impact force reduces the air pockets by forcing the particles closer together. This requires an impact force or manipulation (kneading type) force. 9 Granular Soils Because granular soils do not naturally stick together, you want to use a compaction force that will reduce the voids and make the particles slide together. That force is usually a vibratory force. Mixed Soils Mixed soils require a steady force to move particles closer together and to eliminate air voids.

Asphalt Asphalt is a manufactured product containing Aggregate Filler Binder or chemicals which help hold the aggregate and filler together Asphalt Compaction Strengthens the asphalt structure/surface Increases the life 10

Forces Generated by Compaction Equipment Static Pressure Static Rollers 11 Manipulation Sheepsfoot Rollers Impact Energy Rammers Sheepsfoot Rollers Vibration Energy Vibratory Plates Forward Plates Reversible Plates Vibratory Rollers

Forces Generated by Compaction Equipment Vibration Energy Generated By Vibratory Plates (Forward Plates) Low amplitude High frequency Impact force range from 2200 to 5100 lbs Select impact force depending on application Note these plates travel in one direction Reversible Plates travel in both forward and reverse direction 12

Equipment and Soil Types Compaction Granular Mixed Cohesive 13 Vibratory Plates Reversible Plates Rammers High Frequency Vibratory Plates Low Frequency Low Amplitude High Amplitude Vibrating / Packing Shearing /Compressing Pushes Air & Moisture Out Squeezes Air & moisture Out

In Order to Get Optimum Compaction: -Know the Soil Type 14 -Know the Compaction Specs -Know the Application -Select the Right Machine -Have Good Moisture Content

Factors Affecting Compaction Soil Type - Cohesive, Granular, or Mixed Compaction Specifications Lift Limitations - How deep with the equipment compact 15 Job site Constraints Confined Area Open Area Confined area too small for roller

Rammers vs. Forward Plates on Soils Generally a rammer or forward plate - small areas Vibratory roller - large areas FINE GRAINED 16 SILTS & CLAYS Liquid Limit less than 50% SILTS & CLAYS Liquid Limit more than 50% SOILS COARSE GRAINED GRAVELS More than 50% retained in #4 Sieve SANDS Less than 50% retained in #4 sieve CLEAN GRAVEL GRAVEL / FINES CLEAN SAND SAND / FINES

Vibrating Plates Common names Forward Plates Vibratory or Vibrating Plates S-plates Single-direction Plates Tampers (Tamps) Hand-held Compactors Walk-behind Compactors 17 Photo provided by Wacker Corporation

Common Designs - Forward Plates Determined by base plate size Typically 20 x 24. 18 Determined eccentric force From 2000 lbs to 5100 lbs. Determined by application Dirt - without a water tank Asphalt - with a water tank and sprinkler Landscape stones - with a paving mat

Single Direction Plates Compact Granular Soils using a Vibratory Force Rotating Eccentrics Reduce Friction 19 Gravity Settles the Particles Static weight of machines does little to compact the soil

Factors Affecting Machine Selection For granular soils, a forward vibratory plate works best. 20 Height of lift (amount of soil being added before it is compacted) is important. (22 Max.) Impact force of plate Number of passes needed to achieve compaction

What you want in a plate compactor for soil use. 100ft. Per minute travel speed regardless of impact force. Ability to climb on uneven soil. (Base plate design.) 21 4000 lb. or more impact force for soil applications, this will improve compaction, improve production (less passes) also allow for greater lifts.the higher the impact force the better the compaction results in soil. Steel base plate rather than cast iron, 5 times stronger and won t crack if dropped. Large eccentric housing holding a quart of oil for cooling running/ longer bearing life. Photo provided by Wacker Corporation

Factors Affecting Machine Selection For asphalt patching, a forward vibratory plate works best. 22 Height of lift (amount of asphalt being added before it is compacted) is important. Impact force of plate Number of passes needed to achieve compaction

What you want in the way of features in an asphalt plate. Ideal impact force is 3500 lbs. 5200 vibrations per /min 23 Large 13 qt. Water tank. Removable for filling. Eccentric housing running length of the plate. Housing holds qt. of oil. When oil heats up from eccentric turning, the oil warms the bottom of the plate keeping the asphalt from sticking to bottom of the plate. Sprinkler bar that puts a even flow of water across. Easy serviceability. Water tank that can be added to unit at any time.

Single Direction Plates Will not compact clay - Rammers are required 24

Typical Forward Plate Applications: Asphalt Soil Backfills Bike Paths Foundations Landfills Landscaping Parking Lots Slabs & Floors Sidewalks Trenches Utility Trenches Retaining walls Gas/sewer/water Inside forms Around tanks Footings Curbs Guard rails Drainage ditch Paving stone Bike Paths Cart Paths Confined Areas Driveways Patching Sidewalks Shoulders 25

Forward Plates Also Can Be Used on Asphalt Asphalt Patching Pothole Repair Bike Paths 26

Another common use is for landscaping Setting sod Compacting the base of a stone or brick patio, walkway, path 27

Landscaping Application With the addition of a paving mat, forward plates can be used to set and compact pavers, stone or landscape bricks. The mat prevents the plate from scratching the pavers. 28

Paving Stone Base Preparation with Forward Travel Plate 29

One Additional Area You Might See Forward Plates - Decorative Asphalt 30 Larger Plates are used to press a design into the asphalt. Typically Reversible Plates are used here to get the compaction force.

Cross-selling Opportunities Forward Plates and Rammers are often sold or rented in conjunction with each other Used in landscape applications 31 Used in street repair - rammer to compact base under asphalt patch, plate to compact asphalt patch

Cross-selling Opportunities Add accessories Consider paving mats for landscaping 32 Consider transport wheels Safety Gear (Recommended) Steel-toed safety shoes Head, eye and ear protection

Selling Tips Check the fuel types available on the job site If demo is needed, use lawn, uncompacted dirt or a demo mat. Forward Plates will not demo well on already compacted areas. 33 Plate can be demo d on asphalt but it s unlikely that it will show anything other than how it moves forward

Method Specifications - Soil Specify the method and measuring equipment, if any End Result Wanted The final soil density to be achieved 34 Can be measured by hand or using one of several specific tests Laboratory test Proctor Test Modified Proctor Test Nuclear

Method Specifications - Asphalt Specify the method and measuring equipment End Result Wanted Can be measured using one of several specific tests (Cannot be measured by hand) Laboratory test - requires destruction of a part of the asphalt usually through coring Nuclear 35

Hand Test A common/quick method of measuring moisture in soil, without laboratory instruments: The person doing the test, grabs a handful of soil and squeezes it together. If the soil does not retain its shape or crumbles immediately, it is too dry. 36 If the soil feels like plastic, moisture can be squeezed out of it, it is too wet. Also if it retains its shape when dropped, it is too wet. If the soil can be shaped with no excess moisture, and if it breaks into several pieces when dropped, it is ready to be compacted.

Troubleshooting a Compaction Problem Check these situations with soils Moisture Content Machine Capability Number of Passes Lift (Soil Layer) Thickness Soil Test Sample Check these situations with asphalt Is there water in the tank Content of the asphalt mix Has the asphalt cooled to the point where more compaction is required - i.e, a roller 37