To determine the initial and final setting time and consistency of cement

To determine the initial and final setting time and consistency of cement

Apparatus

Vicatt’s apparatus

300 gm sample of cement

Trowel

Conical hard rubber ring

Water

Graduated cylinder

Procedure

*take the triple beam balance and set the reading of scale to zero

*take a plan and measure its weight

*measure 300gm sample of cement

Take the cylinder and measure 80ml of water now start making the paste doesn’t exceed 1 minute. Alsonote the time of making paste. Now put the paste in the rubber ring from the wider side i.e from down side and make both the upper and lower surface smooth by charging it on a smooth surface now the two tests will be conducted separately by different procedure as

STEPS FOR NORMAL CONSISTANCY TEST

*take the vicatt’s apparatus and place the rubber mould beneath the rod

*set the 10mm diameter plunger on the lower side of rod. Place the lower end of plunger just above the surface of paste

*now release the rod and note down the penetration of plunger in the paste.

*for cement to be normal consistence the penetration should be 10mm according to ASTEM standard on room temperature.

*if it’s not so then the water and cement ratio will not be standard.

Steps for initial setting time tests

*for determining the initial setting time of cement paste set the 1mm diameter needle on the lower end of the rod.

*now release the rod for 30seconds and note the time at which the needle was released, record this in the table along with the penetration of needle in the paste.

*after periodic time again release the rod for 30 seconds note the penetration of the needle in paste

Repeat the above step until the penetration becomes just 25mm which is ASTM standard. Calculate the total time up to this step, which will be initial setting time for the cement. Compare it with the standard time and give comments.

Observation for Consistency Test

Weight of cement =

Amount of water added =

Percentage of water added =

Room temperature =

Water temperature =

PENETRATION =

Result:

“The cement paste is much consistent because the penetration is less 10 mm”

Observation for initial setting time test

ASTM STANDARDS

Initial setting time =

Penetration =

S.No      Time     Penetration

Result:

“Cement is not according to standard”

Steps for final setting time tests

For determining the final setting time of cement pastes set the 5mm diameter needle on the lower end of the rod.

Now again repeat the above steps for noting the final setting time of cement.

The final setting time will be noted when the needle if release does not sink visibility and note leaves no impression on the surface of the paste.

Then compare it with the ASTM standard time. The final setting time can be found by the formula.

Final time = 90+1.2(initial setting time)

ASTM STANDARD TEMPERATURE

Room temperature = 20 c to 27.5 c

Water temperature = 21.6 c to 24.7 c

Observation for final setting time test

ASTM standard

Final setting time =

Penetration =

Final setting time=

So final setting time is

Result:

“The cement is not accurate to the standard”