Softening Point Test 4t1442

University of Technology, Baghdad Iraq Building and Construction Engineering Department Structural engineering Branch Asphalt Laboratory

: ‫إسم التجربة‬

Kadhim Ali Kadhim 3rd

:‫إسم الطالب‬ : ‫الفرع والمرحلة والشعبة‬

20/3/2017

:‫تاريخ التسليم‬

1 | Page

Test No. 4

Softening Point Test Introduction  Bitumen does not melt, but change gradually from sold to liquid  Softening point is the temperature at which the bitumen attains particular degree of softening under specified test conditions  Ring and ball apparatus is used for the test  In principle the balls with a certain weight are placed on a sample of well-placed bitumen and then temperature is raised slowly to liquefy the bitumen in which the temperature at which the bitumen fails to held the balls in space are recorded and this is taken as a softening point.

Objectives:  The softening point test is used to measure and specify the temperature at which bituminous binders begin to show fluidity.  The softening point is also an indicative of the tendency of the material to flow at elevated temperatures encountered in service.  For calculating the penetration index (PI) of the grade asphalt.

Main Principles: This test is used for determining the softening point of bitumen in the range of (30-157PᵒPC) using the ring-ball apparatus immersed in distilled water (30 to 80 PᵒPC). The temperature of a sample is raised at a constant rate and read when the binder has undergone a specified deformation. 2 | Page

A steel ball of 3.5 g is placed on a sample of binder contained in a brass ring which is suspended in a water bath. The bath temperature is raised at 5°C per minute, the binder gradually softens and deforms slowly as the ball falls through the ring. At the moment the bitumen and steel ball touches a base plate 25 mm below the ring, the temperature of the water is recorded. The higher softening point of the two bituminous materials of the same penetration value means a little effect by temperature.

Test Condition:  Select freshly boiled distilled water for softening point between (30-80) C, and USPglycerin for softening point (above 80 PᵒC up to 157 PᵒC).  Use ethylene glycol for softening point between 30 ᵒC and 110 ᵒC.  The temperature of the liquid must raise 5 ᵒC/ min.  The maximum variation for any 1-min. after the first 3 minutes shall be 0.5 ᵒC.

Calculations: Temperature when the softened bitumen touches the metal plate is 50ᵒC for two balls.

Apparatus: 1.Standard ring and ball apparatus assembly as Fig. (4-1) and Fig. (4-2). 2. Heat source 3. Pouring plate treated with a mixture of glycerin and dextrin 4. Thermometer 5. Forceps

3 | Page

4 | Page

Procedures: 1. Heat the sample to a temperature that does not exceed the expected softening point by more than 110°C and time must not exceed 2 hours. 2. Pour a heated sample into the preheated ring which is resting on the pouring plate. 3. Cool the specimen for minimum of 30 min., then cut the excess material off by a hot knife of spatula. 4. Assemble the apparatus with the ring and thermometer and fill the container with distilled water to a depth (102-108) mm. 5. Maintain the container temperature at (5 ±1) PᵒPC for 15 min. place the test container in ice water if necessary. 6. Using forceps place the balls previously adjusted to 5 PᵒPC then apply heat so that the temperature of the liquid is raised 5PᵒPC/ min. The maximum variation for any 1 min after the first 3 min. shall be 0.5 PᵒPC. 7. Record the temperature shown by the thermometer at the instant the ball touches the bottom.

5 | Page

Results and Calculations:

Where: PI = Penetration index =? Pen. = Penetration value = 32.75 mm Trb = softening point value (ᵒC) = 50.5 ᵒC T = Penetration test temperature = 25 ᵒC.

Pi = -1.9381

Questions: Q1. Importance of softening point test and penetration index. The softening point is useful in the classification of bitumen’s. This test method covers the determination of the softening point of bitumen in the range from 30 to 157°C [86 to 315°F] using the ring-and-ball apparatus immersed in distilled water [30 to 80°C] or USP glycerin (above 80 to 157°C). Q2 Find the value of PI, and then compare it with the specifications. Bitumen type PI Blown Bitumen <2 Conventional Paving Bitumen -2 to +2 Temperature Susceptible Bitumen (Tars) <-2

6 | Page

Q3. Explain the relation between penetration and softening point under the effect of temperature. The relationship between the penetration and the softening point is that the softness penetration measures the consistency of asphalt either checking softening point measures the temperature at which the liquid asphalt becomes the greater the softening greater penetration. bituminous materials do not have a definite melting point. Instead, as the temperature rises, these materials slowly change from brittle or very thick and slow-flowing materials to softer and less viscous liquids. For this reason, the determination of 'softening point' must be made by a fixed, arbitrary and closely defined method if results are to be comparable. Being very simple in concept and equipment, the Ring-and-Ball Test has remained a valuable consistency test for control in refining operations, particularly in the production of air-blown bitumen’s. It is also an indirect measure of viscosity or, rather, the temperature at which a given viscosity is evident. The softening point value has particular significance for materials which are to be used as thick films, such as t and crack fillers and roofing materials. A high softening point ensures that they will not flow in service. For a bitumen of a given penetration (determined at 25 C), the higher the softening point the lower the temperature sensitivity. Q4. What is the representation of using the balls in the test? The representation in this experiment the ball because they are easier to get off the asphalt in the model because it does not contain the corners or deviations as to form a homogeneous from all regions. Q5. If you have two types of bitumen, which they have softening points of 55 ᵒC and 60 ᵒC; which one is most affected by temperature, why? Explain that 7 | Page

55 ᵒC is most affected by temperature due to reaches softening point faster than another type which reach softening point in 60ᵒC.

8 | Page

DISCUSSION: The softening point is another important test of bitumen bind and is effecting by change in temperature. This test assures the engineer that the binder being test will have properties similar to this of another binder that has already served successfully. Carefully control of testing temperature and change in temperature must be 5 C/mm and must be calibrated before making the test until to get the resultant more accuracy. Many factor effect on softening point: 1. The water temperature must increase 5 ᵒC/mm. 2. The water must be distilled without air voids or salts because air bubble may assemblages under the sample during heating.

RECOMMENDED VALUE: Softening point indicates the temperature at which binders possess the same viscosity. Bituminous materials do not have a melting point. Rather, the change of state from solid to liquid is gradual over a wide range of temperature. Softening point has particular significance for materials to be used as t and crack fillers. Higher softening point ensures that they will not flow during service. Higher the softening point, lesser the temperature susceptibility. Bitumen with higher softening point is preferred in warmer places.

PRECAUTIONS: (i)

Distilled water should be used as the heating medium.

(ii)

During the conduct of test, the apparatus should not be subjected to vibrations. (iii)The bulb of the thermometer should be at about the same level as the rings. 9 | Page

Safety, Health and Precaution: a. Lab Coat – To prevent the harmful chemical expose to body when accident happened. b. Safety Shoes - Safety footwear is designed to protect feet against a variety of injuries. Impact, compression, chemical splashes and puncture are most common types of injuries. Footwear should be chosen according to the hazard and should be properly rated. c. Safety Glove – To protect hand from expose to harmful chemical.

Conclusion: 1. If the difference between the two samples in the same test exceeds 10 ᵒC, the test must be repeated. 2. As we looking for our sample we can see that it has a low viscosity. 3. When we change the liquid in the bath there will be different in the results because every liquid has a different boiling point and that affected the softening point, so the lower boiling point need low temperature. 4. Because the water has a boiling point @ 1000C; we cannot use it as a liquid for testing material having high softening points. 5. When we increasing the rate of heating, the softening point will be less than the standard (original). 6. If there is sand in the sample the boiling point will be increase, then the softening point will be increase. 7. When we use the same sample many times in this test (reheating and retesting) the results will have an error in the softening point because that will make the material less viscous and we will get error in the results. References Millard, R.S. (1993). Road building in the Tropics. Transport Research Laboratory State-of-the-art Review 9, HMSO, London.

ASTM D36- 95 and AASHTOT53- 06:" Standard test method for softening point bitumen (Ring and Ball Apparatus)"

10 | P a g e

PWD (1992). PWD General Specification. Public Works Department, Singapore 1987 (with amendments, 1992).

11 | P a g e