EFFECTS OF POLYETHYLENE AND KEROSENE ON THE PROPERTIES OF BITUMEN

TEST PROCEDURE & GRAPHICAL PRESENTATION

Specific Gravity Test

           (a)        Wt. of bottle at clean and dry condition = A gm

           (b)        Wt. of (bottle+ water full) at 25⁰ C after 30 min = B gm

           (c)        Wt. of (bottle+ bitumen) at 25⁰ C after 60 min = C gm

           (d)        Wt. of (bottle+ bitumen +water full) at 25⁰ C after 30 min = D gm

                                                    Sp. Gr. = (C-A) / ((B-A)-(D-C))

Penetration Test

(a) Bitumen at 100-1100 C was poured into the container and then cooled to room temperature for one hour.
(b) Container with bitumen was submersed in water at 250 C for one hour.

(c) At constant temp. of 250C, the sample was placed in penetrometer and then readings were recorded for a period of 5 seconds.

Ductility Test

(a) Bitumen was strained through 0.6 mm sieves and then poured into the briquette and was cooled to room temperature for 30 min.
(b) Then sample was placed in water at 25 0C for 30 min.
(c) Excess bitumen was cut off and the briquette was placed in water at 250 C for 1.5 hour. 

(d) Briquette was placed in ductility machine and recorded the reading in cm at which the bitumen threads were broken.

Result of Specific gravity, Penetration and Ductility Test.
(Modified Bitumen Sample made with mixing of Pure Bitumen,
Polyethylene and Kerosene)

Type of Sample	% of Polyethylene content	% of Kerosene content	Specific Gravity	Penetration value	Ductility value
Pure bitumen	0	0	1.020	85	100+
Sample-1	1	1	1.016	41	74
Sample-2	2	2	1.013	53	60
Sample-3	3	3	1.009	50	44
Sample-4	4	4	1.006	41	26
Sample-5	5	5	1.003	38	18

 

Result of Penetration Test (only for % of kerosene content)

Type of Sample	% of Kerosene content	Penetration value
Pure bitumen	0	85
Sample-1	1	80
Sample-2	2	60
Sample-3	3	55
Sample-4	4	54
Sample-5	5	82

 

Solubility Test

(a) 0.50 gm asbestos fiber was thoroughly shaked in 150 cc water.

(b) The crucible was filled with some of the suspension of asbestos in water and applied a light suction to draw off the water, leaving a firm mat of asbestos in the crucible.

(c) The crucible was heated for 10 to 15 min. for the constant weight of A.
(d) 2 gm bitumen was stirred in 100 cc CS2 until all lumps were disappeared and no undissolved sample was adhered to the container. (e) The prepared weighed Gooch crucible was placed in the filter flask. Decanted the solution through the asbestos mat of the crucible with light suction. Removing the crucible from the flask and then heating for 10 to 15 min. for constant weight of B gm.

 

Softening Point Test

(a) Completely fluid bitumen was poured in heated rings placed on metal plate.
(b) After cooling the rings in air for 30 min. the excess bitumen was trimmed.
(c) At this time the temperature of water was kept at 50C for 15 min. and then the balls were placed in position. 

(d) The temperature of water was raised at uniform rate of 50C/min. until the bitumen was softened and touched the bottom plate by sinking of balls.

  

Flash and Fire Point Test

(a) Bitumen was poured into the clean and dried cup up to a filling mark.
(b) Sample was then heated at the rate of 5 to 60C/ min.

(c) Test flame was applied at intervals depending upon the expected flash and fire points.

Result of Solubility, Softening, Flash and Fire Point Test.
(Modified Bitumen Sample made with mixing of Pure Bitumen,
Polyethylene and Kerosene)

Type Of Sample	% of Polyethylene content	% of Kerosene content	Solubility (%)	Softening Point (0C)	Flash Point (0C)	Fire Point (0C)
Pure bitumen	0	0	95.70	43	290	300
Sample-1	1	1	90.05	55	280	295
Sample-2	2	2	85.70	56	270	285
Sample-3	3	3	82.13	57	260	275
Sample-4	4	4	84.30	58	255	270
Sample-5	5	5	87.50	59	250	265

PREPARATION OF SAMPLE FOR MODIFIED BITUMINOUS MIXES

The samples are prepared by adding polyethylene and kerosene with pure bitumen. The amounts of polyethylene and kerosene are added by weight of percentage of pure bitumen separately.

First of all fresh bitumen, without debris and adulterants was collected. The properties of the bitumen were justified. Five bowls for preparing samples was weighed. Hot bitumen was poured in those bowls. The weight of the bitumen was taken. Then polyethylene was weighed with respect to 1%, 2%, 3%, 4%, and 5% weight of the bitumen. The kerosene was also weighed with respect to 1%, 2%, 3%, 4%, and 5% weight of the bitumen. The samples were prepared one after another. At first the bitumen for 1% polyethylene and 1% kerosene content was heated till it fully liquefied and was in a state to dissolve polyethylene and kerosene. The polyethylene bags were gradually left in the bitumen. The softened form of the polyethylene bags was floating on the hot bitumen. But after continuous stirring by steel spoon it was thoroughly mixed with the bitumen. Though the final mixing temperature was not observed but it is assumed that it was near the flash point of the bitumen. There was a little change in the color. This mother sample is kept for further experiments. Thus five samples were prepared with variable polyethylene and kerosene contents. When a test was to be performed the sample was thoroughly heated so that a homogeneous liquid state could be gained and neither precipitation nor floatation nor suspension was observed.

Sample-1. Weight of pure bitumen + 1% polyethylene of pure bitumen + 1% kerosene of pure bitumen (by weight)

Sample-2. Weight of pure bitumen + 2% polyethylene of pure bitumen + 2% kerosene of pure bitumen (by weight)

Sample-3. Weight of pure bitumen + 3% polyethylene of pure bitumen + 3% kerosene of pure bitumen (by weight)

Sample-4. Weight of pure bitumen + 4% polyethylene of pure bitumen + 4% kerosene of pure bitumen (by weight)

Sample-5. Weight of pure bitumen + 5% polyethylene of pure bitumen + 5% kerosene of pure bitumen (by weight).

CHARACTER OF MATERIALS ARE USED IN MODIFIED BITUMINOUS MIXES

Characteristics of Materials used in modified bitumen:

i)          Bitumen

ii)         Polyethylene

i)                    Kerosene

ii)                   Ice

iii)                 Greece

iv)                 Stone aggregate

v)                  Fine aggregate

vi)        Filler materials.

 

Pure Bitumen

i)        Penetration grade: 80/100

ii)       Specific gravity: 1.02

iii)     Ductility value: 100⁺

iv)     Flash point: 290 ⁰C

v)      Fire point: 300 ⁰C

vi)     Softening point: 43 ⁰C

vii)  Solubility: 95.7%

 

Polyethylene

A particular type of polythene bags, transparent in color, mostly representing the low-density polyethylene purchased from the local market is used. Specific gravity of this specimen varies from 0.95 to 0.93.
 

Coarse Aggregate

It was collected from the hump beside Strength of Materials Lab, Transportation Lab, and from site of under construction Computer Science and Engineering building. The white stone aggregate was used with rather mix of black stone. The aggregate was to pass through 20 mm sieve. Other sieves where retained aggregates were collected are   12.5mm, 9.5mm, 4.75mm and 2.36mm.

Fine Aggregate

Fine aggregate of grade 2.36mm passing and retained at 600mm, 300mm, 150mm, and 75 mm. It was collected from the construction site of new student hostel.

Mineral Filler

It was the residuals received after sieving the fine aggregate in the soil lab by mechanical shaker. It was passed through 75mm sieve. 

MARSHALL METHOD OF BITUMINOUS MIXES

Bruce Marshall, formerly Bituminous Engineer with Mississippi State Highway Department, USA formulated Marshall Method for designing bituminous mixes. Marshall’s test procedure was later modified and improved upon by U.S. Corps of Engineer through their extensive research and correlation studies. ASTM and other agencies have standardized the test procedure. Generally, this stability test is applicable to hot-mix design of bitumen and aggregates with maximum size 2.5 cm. In Bangladesh, bituminous concrete mix is commonly designed by Marshall Method.

In this method, the resistance to plastic deformation of cylindrical specimen of bituminous mixer is measured when the same is loaded at the periphery at a rate of 5 cm per minute. The test procedure is used in the design and evaluation of bituminous paving mixes. The test is extensively used in routine test programmers for the paving jobs. There are two major features of the Marshall method of designing mixes namely,

i) Density-voids analysis
ii) Stability-flow test.

The stability of the mix is defined as a maximum load carried by a compacted specimen at a standard test temperature of 60⁰C. The flow is measured as the deformation in units of 0.25mm between no load and maximum load carried by the specimen during stability test. In this test an attempt is made to obtain optimum binder content for the aggregate mix type and traffic intensity.

MIX DESIGN METHOD OF BITUMINOUS MIXES

Various methods of designing the mix proportions of dense bitumen concrete have been evolved. The most widely used methods are the following:

i) The Marshall method.
ii) The Hubbard-field method.
iii) The Hveem method.
iv) The Smith triaxial method

SOLUBILITY TEST OF BITUMINOUS MATERIAL

Pure bitumen is fully soluble in carbon disulphide and carbon tetrachloride. If some quantity remains undissolved it exhibits the quantity of inert mineral present in the bitumen. Bitumen should be soluble in carbon disulphide at least 99%.

FLASH AND FIRE POINT TEST OF BITUMINOUS MATERIAL

Bituminous materials leave out volatiles at high temperatures depending upon their grade. These volatile vapors catch fire causing a flash. This condition is very hazardous and it is therefore essential to determine this temperature for each bitumen grade, so that the paving engineers may restrict the mixing or application temperatures well within the limits. The flash point is the lowest temperatures at which flash occurs due to the ignition of the volatile vapors when a small flame is brought in con tact with the vapors a bituminous product, gradually heated under standardized conditions. As mentioned above, this test is an indication of the critical temperature at and above which suitable precautions should be taken to prevent fire hazards during application. When the bituminous material is further heated to a higher temperature, the material itself catches fire and continues to burn; the lowest temperature causing this condition is the fire point. The fire point is always higher than the flash point of a material. ISI vide specifications I.S: 1209-1258 gives the following definitions.

Flash point-“The flash point of a material is the lowest temperature at which the vapor of substance momentarily takes fire in the form of a flash under specified condition of test.” 

Fire point –“The fire point is the lowest temperature at which the material gets ignited and burns under specified condition of test.”