Standard test method (ASTM D36) for Softening point of bitumin (Ring and ball apparatus ) lab report

Experiment Name :Standard test method (ASTM D36) for Softening point of bitumin (Ring and ball apparatus )

Purpose of the test :

1. This method is useful in determining the consistency of bitumen as one element in establishing the uniformity of shipments or sources of supply.
2. melting point is the temperature at which the bituminous binders have an equal viscosity (i.e. the consistency of all the grades will be same at the softening point e.g. if two samples have softening points of 30 °C and 80 °C respectively, both will have the same consistency at their softening point.).
3.The test given idea of the temperature at which the bitumin materials attain a particular viscosity.
4.Bitumen with higher softening point may be preferred in warmer places.
5.Softening point should be higher than the hottest day temperature, which is anticipated in that area otherwise bitumen may sufficiently soften.

APPARATUS

Rings :A brass shouldered ring.

Balls: A steel ball, 9.53 mm (3/8”) in diameter, weighing between 3.45 and 3.55 grams.

Ball Centering Guide: A guide for centering the ball and made of brass.

Ring Holder: The rings shall be supported on a brass ring holder.
Ring will be supported in a horizontal place with the bottoms of the ring 0.025 m above the upper surface of the bottom plate and a distance of at least 0.013 m and not more than 0.019 m between the bottom plate and the bottom of the bath.
The thermometer shall be suspended so that the bottom of the bulb is level with the bottom of the rings and within 0.013 m of the rings but not touching them.

Pouring plate: A flat smooth brass plate approximately 0.05 by 0.075 m (2 by 3 inch)

Bath : A glass vessel, capable of being heated, not less than 0.085 m in diameter and not less than 0.12m in depth from the bottom of the flare.

Thermometers : From -2 to +80°C.

TEST SPECIMENS

§  Heat the specimen with care to withstand local over heat, with constant stirring until it has become enough fluid in pour. In no other case, however, it will be the temperature be raised to more than 55°C above the expected softening point for tar pitch, or to more than 110 °C above the expected softening point for asphalt. Avoid incorporating air bubbles in the sample.
Bring an asphalt sample to the pouring temperature in not more than 2 hrs. Bring coal tar pitch to the desired pouring conditions in minimum time, not exceeding 30 min.

§  Pour little bit enter of the heated specimen into 2 rings, pre heated to approximately the pouring temperature. While filled the rings will rest on the brass pouring plate, previously treat to prevent bitumin material from adhering to it.

§  Cool the sample disk for a minimum of thirty minute. In no case shall more than 240 min elapse before completion of the test. Cool specimens that are soft at room temperature for at least thirty minute at a minimum of 8 °C bellow the expected soft point.

§  After cooling, cut the excess material off cleanly with a slightly heated knife or spatula. In case the test is repeated, use a clean container and fresh sample to prepare the test specimen.

PROCEDURE

a) –   FOR MATERIALS HAVING SOFTENING POINTS 80°C OR BELOW

gather the apparatus with the ring,( ASTM) Thermometer 15 °C or I5 °F, and ball center guide to the  place and fill up the bath with fresh boiled water to the depth of not less than 0.102m and not more than 0.108m. Maintain the bath temperature at 5 ± 1°C for fifteen minute, placing the test container in cold water if necessary. Using pincers place a ball; previously adjust to the bath temperature, in each ball center guide.

Attach heat in such a method in that  temperature of the liquid is increased 5°C/minute. Ignore the effect of drafts, using shield if needed. (Rigid adherence to the prescribed rate of heating is absolutely essential for reproducibility of results. Either a gas burner or electric heater may be used; however, the latter must be of the low-lag, variable output type to maintain the necessary rate of heating.)

The rate of rise of temperature shall be uniform and shall not be averaged over the period of the test. The maximum permissible variation of any 1-mm period after the first 3 mm shall be ± 0.5°C. Reject all tests in which the rate of rise does not fall within these limits.

Record for every rings and ball to the temperature showed by the thermometer at the trice the sample surrounding the ball touch to the  bottom plate. commit no correction for the emergent stem of the thermometer. If the difference between the values obtain in the duplicate determination exceeds 1°C again to the test.

b) –   FOR MATERIALS HAVING SOFTENING POINTS ABOVE 80°C

Follow the same procedure as described above, except use USP glycerin instead of water and use ASTM Thermometer l6°C or 16°F. The starting temperature of the glycerin bath shall be 32°C.

OBSERVATIONS & RESULTS:

COMMENTS

 The experiment has been performed successfully and the softening point came out to be 46.4^oC. Bitumen having this softening point should not be used in Lahore as the city’s highest maximum temperature was 48.3 °C recorded on May 30, 1944  And 48 °C was recorded on June 10, 2007. At the time the meteorological office recorded this official temperature in the shade, it reported a heat index in direct sunlight of 55 °C. So to ignore the matter of  Rutting and bleeding this bitumin should not be used.