WORKABILITY OF CONCRETE – VEE BEE TEST

[Srinivasan]

WORKABILITY OF CONCRETE – VEE BEE TEST

AIM: To find workability of concrete by Vee-Bee consistency test in terms of Vee Bee Seconds

APPARATUS:

Vee Bee consistometer, Stopwatch, Balance, Tray, Tamping rod, measuring jar, Weights and Trowels.

THEORY:
The consistometer is used for determining the consistency of concrete by vibrating and transforming a concrete specimen from the shape of conical frustum into a cylinder.

DESCRIPTION:
The consistometer consists of a

• A vibrator table, which vibrates a rate of 3000 vibrations / min.
• A metal pot, which holds the specimen when the concrete is vibrated. It is secured to the vibrator table by bolts.
• Slump cone of 300 mm high, 200 mm at the bottom and 100 mm at the top (Open both ends).
• Swivel arm holder: A tube, which is fixed the rear of the base of the vibrator table. It has 4 positioning slots for swivel arm to position the metal cone over the slump cone or Perspex disc on the specimen or to position both of them away.
• Swivel arms the Swivel moves freely inside the swivel arm holder. A metal rod and a guide sleeve are fixed to the swivel arm. The graduated metal rod passes through the guide sleeve.
• Metal cone - this is in the form of a frustum of cone with open ends (funnel). This is fixed to the swivel arm
• Graduated rod
• Tamping rod. A metal rod of 16 mm x 60 cm. long with one end bullet ended.

PROCEDURE:

• Position the metal cone over the slump cone. Place the concrete inside the slump cone in 4 layers each approximately 1/4 of the height. Strokes are applied by the rounded end of the tamping rod. Distribute the strokes in a uniform manner over the cross section.
• After the top layer has been rodded, position the metal cone of the swivel arm away, and strike off the concrete, level with the top of the cone using a trowel so that the mould is exactly filled.
• Remove any material spilled inside the metal pot or sticking on to the side of the slump filled.
• Position the Perspex disc over the cone and note down the reading on the graduated rod (L1). After keeping the disc away, lift the slump cone vertically and remove.
• Position the disc over the concrete. Note down the reading of the graduated rod (L2). The difference in the readings gives the slump in Centimeters.
• Switch on the vibrator starting a stopwatch simultaneously. Allow the

concrete to spread out in the pot. When the whole concrete surface uniformly adheres to the Perspex disc, stop the watch, simultaneously, switch off the vibrator. Note down the time in seconds. Also note the reading on the graduated rod (L3).

• The consistency of the concrete is expressed in Vee-Bee degrees which are

equal to the time in seconds.

• Repeat the procedure of different W/C ratios viz.: 0.4, 0.5, 0.55, 0.6 & 0.65.
• Draw a graph between slump in centimeters and Vee – Bee Degrees.

Knowing the dia of the disc and the height of the concrete after Vibration (30+ L1 – L3), the Volume of the concrete can be computed

 

[Gora Watson Simon]

WORKABILITY OF CONCRETE – VEE BEE TEST

AIM: To find workability of concrete by Vee-Bee consistency test in terms of Vee Bee Seconds

APPARATUS:

Vee Bee consistometer, Stopwatch, Balance, Tray, Tamping rod, measuring jar, Weights and Trowels.

THEORY:
The consistometer is used for determining the consistency of concrete by vibrating and transforming a concrete specimen from the shape of conical frustum into a cylinder.

DESCRIPTION:
The consistometer consists of a

• A vibrator table, which vibrates a rate of 3000 vibrations / min.
• A metal pot, which holds the specimen when the concrete is vibrated. It is secured to the vibrator table by bolts.
• Slump cone of 300 mm high, 200 mm at the bottom and 100 mm at the top (Open both ends).
• Swivel arm holder: A tube, which is fixed the rear of the base of the vibrator table. It has 4 positioning slots for swivel arm to position the metal cone over the slump cone or Perspex disc on the specimen or to position both of them away.
• Swivel arms the Swivel moves freely inside the swivel arm holder. A metal rod and a guide sleeve are fixed to the swivel arm. The graduated metal rod passes through the guide sleeve.
• Metal cone - this is in the form of a frustum of cone with open ends (funnel). This is fixed to the swivel arm
• Graduated rod
• Tamping rod. A metal rod of 16 mm x 60 cm. long with one end bullet ended.

PROCEDURE:

• Position the metal cone over the slump cone. Place the concrete inside the slump cone in 4 layers each approximately 1/4 of the height. Strokes are applied by the rounded end of the tamping rod. Distribute the strokes in a uniform manner over the cross section.
• After the top layer has been rodded, position the metal cone of the swivel arm away, and strike off the concrete, level with the top of the cone using a trowel so that the mould is exactly filled.
• Remove any material spilled inside the metal pot or sticking on to the side of the slump filled.
• Position the Perspex disc over the cone and note down the reading on the graduated rod (L1). After keeping the disc away, lift the slump cone vertically and remove.
• Position the disc over the concrete. Note down the reading of the graduated rod (L2). The difference in the readings gives the slump in Centimeters.
• Switch on the vibrator starting a stopwatch simultaneously. Allow the

concrete to spread out in the pot. When the whole concrete surface uniformly adheres to the Perspex disc, stop the watch, simultaneously, switch off the vibrator. Note down the time in seconds. Also note the reading on the graduated rod (L3).

• The consistency of the concrete is expressed in Vee-Bee degrees which are

equal to the time in seconds.

• Repeat the procedure of different W/C ratios viz.: 0.4, 0.5, 0.55, 0.6 & 0.65.
• Draw a graph between slump in centimeters and Vee – Bee Degrees.

Knowing the dia of the disc and the height of the concrete after Vibration (30+ L1 – L3), the Volume of the concrete can be computed
View attachment 1429

Thanks for that resources full information, may you kindly be my mentor.