What Is Self Compact Concrete?
Making concrete structures without vibration has been done in the past. For example, the placement of concrete under-water is done by the use of tremie without vibration. Shaft concrete and mass concrete may be successfully placed without vibration.
But the above examples of concrete are normally of lower strength and difficult to obtain consistent quality. Modern application of SCC (self-compacting concrete) is focussed on high performance, better and more reliable, and uniform quality.
List of Test Methods for Workability Properties of Self Compacting Concrete (SCC).
- Slump flow by Abrams cone.
- T50 cm Slump flow
- V-funnel at T5 minutes
- GTM Screen Stability Test
In this article, we are discussion & Procedure Slump Flow Test
What Is Slump Flow Test?
The slump flow test is done to assess horizontal flow of concrete at the absence of obstructions. It is the most commonly used test and gives a good assessment of filling ability. It may be used at the site. The test also indicates the resistance to segregation.
Equipment for Slump Flow Test
- Slump Cone
The usual slump cone having a base diameter of 200 mm, top dia. 100mm, and height 300mm are used.
- Base Plate For Slump Flow test
A stiff base plate square in shape is having at least a 700 mm side. Concentric circles are marked around the center point where the slump cone is to place. A firm circle is drawn at 500 mm diameter
- A trowel
This tool is used to place cement mortar.
This use in QC department for the material.
- Measuring tape
To measure the length.
Use for time record
Procedure of Slump Flow Test
- About 6 liters of concrete is needed for this test.
- Place the baseplate on level ground.
- Keep the slump cone centrally on the base plate.
- Fill the cone with the scoop.
- Do not tamp.
- Simply strike off the concrete level with the trowel.
- Remove the surplus concrete lying on-base place.
- Raise the cone vertically and allow the concrete to flow freely.
- Measure the final diameter of the concrete in two perpendicular directions and calculate the average of the two diameters.
- This is the slump flow in mm.
- Note that there is no water or cement paste or mortar without coarse aggregate is seen at the edge of the spread concrete.
Calculations of Slump Flow Test
- Largest diameter of slump flow (dm) = _______ mm
- Diameter perpendicular to largest diameter (dr) = _______ mm
- Slump flow = (dm+dr) /1
- Results of Slump Flow Test
- The slump flow of Self compacting concrete is _______ mm
- Interpretation of Slump Flow Test
- The higher the flow value, the greater its ability to fill formwork under its own weight.
- A value of at least 650 mm is required for SCC (Self Compact Concrete).
- In case of severe segregation, most coarse aggregate will remain in the center of the pool of concrete and mortar and paste at the periphery of concrete.
T50 Slump Flow Test
- The procedure for this test is same as for slump flow test. When the slump cone is lifted, start the stopwatch and find the time taken for the concrete to reach a 500 mm mark.
- This time is called T50 time.
- This is an indication of the rate of spread of concrete.
- A lower time indicates greater flowability.
- It is suggested that T50 time may be 2 to 5 secs.