How will trucks be checked on-site when receiving concrete?
A. Revolution Counter
B. Ticket Checked for Concrete Batching time and Slump Value at the plant.
C. Slump Test.
D. Temperature Test (32 C maximum @ Site).
E. Assure Lab Technician is present at the site and performs testing.
F. 6 Cubes or 4 Cylinders should be taken per 50cum or recommended in the project specification.
What is the purpose of the slump test?
To determine the consistency of the workability of the concrete mix and to check for the required slumps.
What are allowable slumps?
2.5cm to 7.5cm (for vibrated structure and without admixture ) and If with admixture and plasticizer, Slump depends upon the design mix. Slump shall be checked as per design mix.
What is a plasticizer?
Usually applied at a low water-cement ratio concrete to make it workable.
What is the maximum temperature of concrete that can be poured into a concrete structure?
32 Degrees C.
How would you know if the concrete has gained its initial set?
If there is no more water seen (brightness) on the surface of the concrete, or if there is no water on the surface of the concrete.
If agitated concrete is discharged after more than one hour, what will happen?
The concrete is over mixed, becomes hot, and the strength is reduced
How many layers are in the concrete cube?
Concrete Cube is cast in 3 layers.
How many strokes are done in one layer in a concrete cube?
35 Strokes in one layer.
What is the size of rode used in concrete cube casting and slump test?
Dia – 16mm and 600mm length.
What is the size of a concrete cube?
150mm X 150mm X 150mm.
What is the size of slump cones?
Height – 30cm, Top of Cone – 10cm, and Bottom of cone – 20cm.
How many layers are in the slump test?
3 Layers in ASTM and BS but 4 Layers in Indian standard.
How many strokes are done in one layer in a slump test?