Eng. Malek AbuwardaLecture 11 P1

Construction Methods

Lecture 11

Compaction Equipment and Procedures

Eng. Malek Abuwarda

Compaction Equipment and Procedures Compaction Operations

The major variables to be considered include soil moisture content, lift thickness, number of passes used, ground contact pressure, compactor weight, and compactor speed.

Soil MoistureThe optimum water content for compaction varies from about 12 to

25% for fine-grained soils and from 7 to 12% for well-granular soils.When it is necessary to add water consider the

Amount of water required Rate of water applicationMethod of applicationEffects of the climate and weather

Lecture 11 P2

Eng. Malek Abuwarda

Compaction Equipment and Procedures Amount of water required

The amount of water that must added or removed is normally computed in cubic meter per station.

It is good practice to adjust the desired moisture content 2% above optimum, but this depends on the environmental conditions.

Effects of WeatherWeather conditions substantially affect soil moisture content. Cold,

rainy, and cloudy weather will allow a soil to retain water.Hot, dry, sunny and windy weather is conductive to drying the soil.

Lecture 11 P3

water (CM) = desired dry density (t/m3) desired WC% soil WC%

Compacted vol. of soil (CM)100

1 (t/m3)

Eng. Malek Abuwarda

Compaction Equipment and Procedures Example

Job specifications require placement of the embankment fill soil in 25cm (compacted). The desired dry unit weight is 1.8t/m3. The laboratory indicates that the optimum moisture content (OMC) of the soil is 12%. Soil tests indicate that the water content of the borrow material is 5%. The roadway lift to be placed is 12m wide.

Compute the amount of water in cubic meter to add on a per station.

Lecture 11 P4

3 12 50 0.2512 5( ) 1.8

100 118.9 /

water m

cube station

Solution

Take the distance between station is 50m

Eng. Malek Abuwarda

Compaction Equipment and Procedures Application Methods

Regardless of which method of application is used, it is important to ensure that the proper application rate is achieved and that the water is uniformly distributed.

Lecture 11 P5

Eng. Malek Abuwarda

Compaction Equipment and Procedures

Lecture 11 P6

Eng. Malek Abuwarda

Compaction Equipment and Procedures Typical Effect of Number of Passes

Lecture 11 P7

Eng. Malek Abuwarda

Compaction Equipment and Procedures Mixing and Blending

Whether adding water to a soil to increase the moisture content or adding a drying agent to reduce it, it is essential to mix the water or drying agent thoroughly and uniformly with the soil.

Even if additional water is not needed, mixing may still be necessary to ensure a uniform distribution of existing moisture.

Mixing can be accomplished using motor graders.

Lecture 11 P8

Eng. Malek Abuwarda

Compaction Equipment and Procedures Grading and Finishing

Grading is the process of bringing earthwork to the desired shape and elevation.

Finish grading, or simply finishing, involves smoothing slopes, shaping ditches, and bringing the earthwork to the elevation required by the plans and specification.

Lecture 11 P9

Eng. Malek Abuwarda

Compaction Equipment and Procedures Components of Motor Grader

Moldboard (Blade)ScariferGraders may also be equipped with light rear-mounted Rippers

Lecture 11 P10

Eng. Malek Abuwarda

Compaction Equipment and Procedures

Lecture 11 P11

Eng. Malek Abuwarda

Compaction Equipment and Procedures Moldboard

Lecture 11 P12

Eng. Malek Abuwarda

Compaction Equipment and Procedures Moldboard

Lecture 11 P13

Eng. Malek Abuwarda

Compaction Equipment and Procedures Moldboard

Lecture 11 P14

Eng. Malek Abuwarda

Compaction Equipment and Procedures Trimmers

Trimmers are specialty machines to fine finishing for special jobs.The result is better accuracy and greater production compared to

motor graders.It is capable of scarifying and removing soil and old asphalt

pavement.

Lecture 11 P15