# Test for Bleeding of Concrete

The relative quantity of mixing water, which will bleed from fresh concrete mix can be determined by the test for bleeding of concrete.

## Apparatus

Apparatus and accesory required for bleeding test of concrete are as follows:

1. Cylindrical container
2. Weighing scale
3. Pipette
4. Tamping bar

### 1. Cylindrical Container

container used for this test is made of steel and has a capacity of 0.01 m3. The inside diameter and the inside height of the cylinder 250 mm and 280 mm respectively.

### 2. Weighing Scale

Digital weighing scale of accuracy up to 0.005 is required for weighing specimen samples.

### 3. Pipette

Pipette is used to draw off the bleed water from specimen.

### 4. Tamping bar

bar used in this test is a rounded steel bar of diameter 16 mm and 610 mm length.

Graduated cylinder of 100 cm3 is required to measure the water quantity.

## Test Procedure

• Firstly, take quantity of freshly mixed concrete of known water content.
• Fill the Cylindrical container with mix in 5 layers of each 50 mm.
• Each layer should be tamped or compacted by giving minimum 60 strokes using tamping bar after filling,
• After compacting the final layer, surface is and smoothed by troweling.
• Immediately after troweling, note down the time and weigh the container.
• After weighing, place the container in a surface which should be free from vibrations.
• Top of the container should be closed with or covered to prevent evaporation of bleed water.
• This test should be conducted at a temperature of 25oc to 29oC.
• For every 10 minutes, draw off the water accumulated on the top surface of concrete using and collect it in cylinder. This should be done for 40 minutes.
• After 40 minutes, collect water for every 30 minutes and continue until bleeding stops.
• If it is hard to draw off water on top surface, slightly tilt the container and collect it.
• note the weight of water collected in jar.

## Calculations

Bleeding water % = (B/W) X 100 --------- Equation (1)

Where   B = Total quantity of bleeding water

W = Total quantity of water in the concrete mix

Or

Bleeding water percentage of net mixing water contained with in the test specimen is,

Where, D = Total mass of bleeding water, Kg

w = Net mass of water (total water – water absorbed by aggregates)

S = Total mass of concrete mix

W = Total mass of water in the mix

Equation (2) is more accurate than equation (1), since water absorbed by aggregates is considering here.

## Result

Bleeding water percentage for the given concrete mix = _______ %