The principle of compacting factor is determining the degree of compaction ... in
the test to density of same concrete fully compacted) This test primarily for use in
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Experiment No. 12 Compacting Factor Test Introduction: The principle of compacting factor is determining the degree of compaction achieved by a standard amount of work done by allowing the concrete to fall through a standard height. The degree of compaction is measured by the density ratio, ( The ratio of density actually achieved in the test to density of same concrete fully compacted) This test primarily for use in the laboratory but it can also be used in the field, useful for concrete mixes of low, medium and high workable.
Purpose To determine the compacting factor or the degree of compaction that achieved by applying a standard amount of work, which gives an indication to the workability of fresh concrete
Materials Same fresh concrete used for slump test, uses also to test the degree of compaction of fresh concrete
Apparatus Compacting factor apparatus which consists of: Upper hopper with a dimension ( Top: 254 mm , bottom: 127 mm and height: 279 mm) , lower hopper with a dimension ( Top : 229 , Bottom: 127, and height : 229 mm ) and cylinder (with dia. 152 and height 305 mm ) connected, the total height measuring from the base of upper hopper to the base of cylinder about 1 m.
Procedure 1. Clean and moist the internal sides of the upper and lower hoppers using dampen cloth. 2. Place the sample of prepared fresh concrete in the upper hopper; and let the sliding door closed. 3. Open the top slide door , so that the concrete falls into the lower hopper 4. Open the slide door of the lower hopper, so that the concrete is allowed to fall into the cylinder 5. Remove the excess concrete above the top level of the cylinder, the outside is wiped clean 6. Weigh the concrete in the cylinder that is partially compacted let be W1 7. Empty the cylinder and fill it with the concrete from the same sample in 3 layers approximately of equal volumes. 8. Each layer heavily rammed or vibrated so as to obtain full compaction 9. Struck off level the top surface of the fully compacted concrete with the top of the cylinder , and weigh it , let to be W2
Calculation 𝑇ℎ𝑒 𝐶𝑜𝑚𝑝𝑎𝑐𝑡𝑖𝑛𝑔 𝐹𝑎𝑐𝑡𝑜𝑟 =
𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑝𝑎𝑟𝑡𝑖𝑎𝑙𝑙𝑦 𝑐𝑜𝑚𝑝𝑎𝑐𝑡𝑒𝑑 𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒(𝑤1) 𝑊𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝐹𝑢𝑙𝑙𝑦 𝐶𝑜𝑚𝑝𝑎𝑐𝑡𝑒𝑑 𝐶𝑜𝑛𝑐𝑟𝑒𝑡𝑒 (𝑤2)
Experiment No. 13: Vebe Test Introduction: This test is a good laboratory test; the principle is the amount of work required for the fresh concrete to transform its shape from conical to cylindrical. This method is very suitable for very dry mixes.
Purpose: This test is to determine the amount of work expressed by time in seconds of working the vibrating machine required to transform shape of concrete from the slump cone to cylindrical shape. This time is a measure to workability of fresh concrete.
Material Same fresh concrete used for slump test, flow test and compacting factor test, uses also to test the workability of fresh concrete by determining Vebe time.
Apparatus Vebe consistometer apparatus which includes the followings: 1. Slump con , the same con uses for slump test placed inside the sheet metal cylindrical pot 2. Cylindrical container placed on a vibrating table 3. Glass disc attached to the swivel arm 4. Electrical vibrator. Standard tamping rod Scoop Stop watch
Procedure 1. Place the slump cone inside the sheet metal cylindrical pot of the consistometer 2. Fill slump con with fresh concrete in 3 layers, each layer compacted 25 times stroke using tamping rod. 3. Rise up the slump cone vertically 4. Let the glass disc to attach the surface of the slumped concrete in the cylindrical pot. 5. Switch on the electrical vibrator and simultaneously a stop watch started. 6. Continue the vibration until the conical shape of the concrete disappears and the concrete assumes a cylindrical shape. This can be judged by observing the glass disc from the top for disappearance of transparency 7. Switch off the stop watch when the concrete shape assumed is fully cylindrical.
8. Record the time in seconds required for the concrete to change from conical to cylindrical, this gives a measure to workability of concrete.
Upper hopper Rotating arm
Plastic disc
Slump cone container Lower hopper Vebe Table
Cylinder
Compacting Factor test apparatus
Ve be consistometer test apparatus
Data Sheet
Tests Name: Compaction Factor and Vebe Test No.: 12 and 13 Student Name: Student Class and Group:
Group No. 1 2
Mix proportion
w/c ratio
Compacting Factor (C.F)
V.B time Seconds
Degree of Workability
