This portion of the paper outlines the different stages undertaken during the research to ensure a dependable outcome. Figure 1, displayed below, illustrates the research flowchart detailing the various steps employed to finalize the study.
2.1. Preparation of LDPE and WCO modified bitumen
In many regions of India, Viscosity Grade 30 (VG-30) virgin bitumen is commonly used. Because of its widespread use, VG-30 was selected as the foundational material for producing asphalt samples that have been modified with LDPE and WCO. Table 1, presented below, displays the values for penetration, softening point, specific gravity, ductility, flash point, and fire point for this selected grade of virgin bitumen.
Table 1: Characteristics check of VG-30 bitumen.
The used milk pouches, as depicted in Figure 2a, were gathered from households, cleaned, dried, and subsequently transformed into small 5 mm-sized particles to create LDPE additives, as shown in Figure 2b. The waste cooking oil (WCO), seen in Figure 2c and collected from a street vendor, underwent filtration using a strainer to eliminate any remnants of fried food. Three sets of modified bitumen samples, which integrated LDPE and WCO, as illustrated in Figure 2d, were produced by blending these components at a temperature of approximately 180°C.
In the production of each sample, the goal was to create approximately 500 grams of LDPE and WCO modified bitumen. The LDPE dosages, replacing part of the bitumen, were designated as 4%, 4.5%, in addition to the constant 10% WCO by the mass of the modified asphalt binder sample. The specific weights of these components utilized to formulate various modifier compositions are detailed in Table 2 below.
Table 2: Weight of different constituents per 500 gm of samples.
Bitumen weight (gm)
|
LDPE and WCO (%)
|
LDPE and WCO by weight (gm)
|
500
|
Nil
|
Nil
|
430
|
4 and 10
|
20 and 50
|
427.5
|
4.5 and 10
|
22.5 and 50
|
425
|
5 and 10
|
25 and 50
|
2.2. Testing sketch out
This section of the document provides a concise overview of the different tests conducted on the prepared samples in accordance with IS code specifications. Table 3 outlines the testing summary for this examination.
Table 3: Testing sketch out.
Samples taken
|
Test
|
Specification
|
VG-30 bitumen and (LDPE+WCO) modified bitumen
|
Penetration Index
Softening point (oC)
Specific gravity
Ductility (cm)
Flash point (oC)
Fire point (oC)
|
IS: 1203-1978
IS: 1205-1978
IS: 1202-1978
IS: 1208-1978
IS: 1209-1978
IS: 1209-1978
|
Penetration Test Procedure IS: 1203-1978
1.Begin by heating the sample until it reaches a liquid state.
2.Pour the liquid into a container, ensuring that, upon cooling, the sample's depth exceeds the expected penetration by at least 10mm.
3.Let it cool at room temperature.
4.Clean the needle and position a weight on top of it.
5.Utilize a water bath to maintain the specimen's temperature.
6.Position the needle so that it lightly touches the bitumen's surface.
7.Start a stopwatch and allow the penetration needle to freely penetrate for 5 seconds. Halt the penetration after this duration.
8.The resulting value indicates the bitumen grade.
It's advisable to take at least three readings for accuracy.
According to figure [3], this is the final set-up for the penetration test.
Figure [ 3] is essentially determing the penetration value of bitumen and how bitumen is behaving in hot and cold climate.
Softening point Test Procedure IS: 1205-1978
1.The sample material is heated to a temperature ranging from 75°C to 100°C above its estimated softening point until it becomes completely liquid, and it is then poured into heated rings positioned on a metal plate.
2.To prevent the bitumen from sticking to the metal plate, a coating of a glycerin and dextrin solution is applied.
3.After letting the rings cool in the open air for 30 minutes, any excess bitumen is trimmed, and the rings are placed on a support.
4.During this stage, distilled water is kept at a temperature of 5°C. This temperature is maintained for 15 minutes, after which the balls are positioned.
5.Next, the water temperature is gradually increased at a constant rate of 5°C per minute using a controlled heating unit until the bitumen softens, causing the balls to sink and touch the bottom plate. At least two observations are recorded. For materials with a softening point above 80°C, glycerin serves as the heating medium, and the initial temperature is set at 35°C instead of 5°C.
As shown in Figure 4, the softening point test for bitumen is a crucial examination aimed at determining the temperature at which bitumen softens or becomes pliable. This test's primary objective is to ascertain the temperature at which bitumen undergoes a significant change in its physical properties. This information holds substantial importance for various applications in the construction and engineering sectors.
Specific gravity Test Procedure IS: 1202-1978
1.Begin by cleaning, drying, and weighing the specific gravity bottle along with its stopper, recorded as 'Weight A.'
2.Fill the specific gravity bottle with freshly boiled distilled water and securely seal it with the stopper. Place it in a water bath at a temperature of 27.0 ± 1°C for at least 30 minutes and measure its weight, noted as 'Weight B.'
3.Next, weigh the specific gravity bottle when it is half-filled with the material, recorded as 'Weight C.'
4.Weigh the specific gravity bottle when it is half-filled with the material and the other half with distilled water, noted as 'Weight D.'
5.Finally, measure the weight of the specific gravity bottle when it is completely filled with the material, recorded as 'Weight E.'
Test Reports
i) To determine the specific gravity of solids and semi-solids, you can use the formula: Specific gravity (Solids and semi-solids) = (Weight C - Weight A) / [(Weight B - Weight A) - (Weight D - Weight C)].
ii) For measuring the specific gravity of liquids, use the formula: Specific gravity (Liquids) = (Weight E - Weight A) / (Weight B - Weight A).
Specific gravity of bitumen is defined as the ratio of the mass of a given volume of bitumen with known content to the mass of an equal volume of water at 27°C. You can determine specific gravity using a pycnometer or by creating a cube specimen of bitumen in its semi-solid or solid state. The specific gravity of bitumen typically falls within the range of 0.97 to 1.02.
Ductility Test Procedure IS: 1208-1978
1.Begin by completely melting the test bituminous material at a temperature ranging from 75°C to 100°C above its estimated softening point until it becomes entirely fluid.
2.Filter the fluid through an IS sieve with a mesh size of 30.
Once the fluid is thoroughly mixed, pour it into the mold assembly and position it on a brass plate. To prevent the test material from sticking, coat both the plate's surface and the inner sides of the mold with either mercury or a mixture of equal parts glycerin and dextrine.
3.After approximately 30-40 minutes, place the plate assembly along with the sample in a water bath, maintaining the water bath's temperature at 27°C for half an hour.
4.Remove the sample and mold assembly from the water bath and trim the specimen, leveling its surface using a heated knife.
5.Return the mold assembly to the water bath for 80 to 90 minutes.
6.Carefully remove the sides of the mold.
7.Securely hook the clips onto the testing machine without applying any initial strain.
8.Adjust the pointer to read zero.
9.Initiate the testing machine and horizontally pull the clips at a consistent speed of 50 mm per minute.
10.Record the distance at which the bitumen thread of the specimen breaks.
Figure [5] is the final set-up for the ductility test of bitumen.
As illustrated in Figure 5, the ultimate objective of the ductility test for bitumen is to assess the bituminous material's capacity to undergo deformation under tensile stress without experiencing fractures or breakage. More precisely, this test quantifies the extent to which a bitumen sample can elongate or stretch before reaching the point of rupture. The ductility test offers critical insights into the physical characteristics of bitumen, which hold significant importance in a wide range of engineering and construction applications.
Flash and Fire point Test Procedure IS: 1208-1978
A. Flash point
1.Begin by softening the bitumen in the temperature range of 75 to 100°C. Ensure thorough stirring to eliminate any air bubbles and moisture.
2.Fill the designated cup with the material to be tested, up to the specified mark. Position it on the bath, secure the open clip, and insert the thermometer, choosing either a high or low range as required. Also, introduce the stirrer for agitation.
3.Ignite the test flame and adjust it accordingly. Apply heat at a controlled rate, ensuring that the temperature increase, as recorded by the thermometer, falls within the range of 5 to 6°C per minute.
4.The open flash point is identified as the temperature at which an initial flash becomes visible at any point on the material's surface in the cup. It's crucial to distinguish the true flash from any bluish halo that may surround the test flame. While conducting the test, refrain from stirring.
5.The flash point is determined as the temperature reading on the thermometer precisely when the flash occurs.
B. Fire Point
1.Following the flash point, proceed with heating at a controlled pace, ensuring that the temperature rise, as monitored by the thermometer, falls within the range of 5 to 6°C per minute.
2.Illuminate the test flame and set it to a size equivalent to a 4mm diameter bead.
These tests were carried out on the previously prepared modified bitumen samples. To ensure accurate results, equivalent test specimens were also created, and each one was analyzed for the same bitumen characteristics. The assessment of brittleness, consistency, and water resistance in the modified bitumen samples involved conducting penetration and ductility tests at 25°C. In contrast, the performance of these modified samples under high-temperature conditions was determined through softening and flammability tests. Additionally, specific gravity tests were conducted on the modified bitumen samples to ascertain whether conventional testing methods used for pure bitumen could also be applied to them.