Engineering and Construction of Bitumen - Lab Report Example

Lab Report, Engineering and Construction: Bitumen In this laboratory, the tests were performed with a view to determine thesoftening point of a sample of bitumen (2) determine the penetration value of three samples of the penetration grade bitumen (3) identify which of the three given samples correlate to the bitumen that was used in ring and ball test in order to ascertain the Penetration Index (PI) of the bitumen, and (4) determining the viscosity of a given sample of cutback bitumen based on the British standard BS2000: Part 58. To this end, three samples of bitumen were prepared and tested. This involved three testes. Each test aimed at measuring the depth of to which a standard needle would penetrate the sample of bitumen under standard conditions. There were two conditions hereunder: temperature of 25 degrees Celsius and a load of 100 grams for a given time frame. The result of this test revealed the average value of depth of penetration to be 49.33 dmm. Apparently, the bitumen sample (44-60) grade bitumen. When a steel ball of diameter 9.5 mm was allowed to fall through the sample of bitumen to a depth of 25 mm, the study found 61.5 degrees Celsius as the softening point temperature. INTRODUCTION Bitumen is non-crystalline oil based viscous substance or solid, which is derived from petroleum, which exists as a by-product of oil refinery process. It is soluble in carbon disulphide and has adhesive properties. Bitumen is made up of organic liquids mixtures, which are characteristically highly viscous, sticky, and black. It is mainly composed of highly condensed polycyclic aromatic hydrocarbon. In the refinery process, bitumen is often obtain in a process involving the removal of lighter fractions such as petrol, diesel, and liquid petroleum through distilling blends of crude oil in the refinery process. Bitumen is widely used in the construction industry. It is primarily used as a key constituent of most products that used in roofing and paving applications. Bitumen is also largely used in asphalt as a binder for roads. Besides, bitumen is used in paved regions such as car parks, footways, and airport runways. Natural bitumen is often formed from the oil that has already been generated and migrated into reservoirs. This oil should also have been subjected to normal processes alongside other effects. This study explored various properties of bitumen as used in the construction industry. The focus was determining the softening point of a sample of bitumen, the penetration value of three samples of the penetration grade bitumen, identifying which of the three given samples correlate to the bitumen that was used in ring and ball test in order to ascertain the Penetration Index (PI) of the bitumen, and determining the viscosity of a given sample of cutback bitumen. PROCEDURE The Needle was thoroughly cleaned to help get good measurements. The temperature of water surrounding the bitumen sample was maintained at 25ºC as demonstrated in figure 1.1. The needle was moved downwardly until it touched the surface of a sample of bitumen The settings of the gauge was checked and its workability confirmed The needle was loaded with 100 grams load in a period of 5s After the needle had penetrated the bitumen sample The depth of the needle was noted down. This test was repeated twice as the needle was maintained at 10 mm from a Figure 1.1: Procedure for evaluating the bitumen softening point temperature. The bitumen sample in a brass rig was prepared The sample was moved to the water bath. The steel ball was placed on a top surface of the sample The temperature for the water bath was gradually increased. As the ball fell through the bitumen sample, the corresponded temperatures were noted. This procedure was repeated to ensure data validity is achieved Finally the average of the two values were recorded. Results The Needle Penetration Test Table 1.1 displays results for the needle penetration into bitumen sample. From the three tests, the final value was found by averaging the three values. Table 1.1 showing penetration test results Sample/Determination 1st Test 2nd Test 3rd Test Average Grade 4B16 49 47 52 49.33 44-60 The result of this study evidently indicate the tested sample of bitumen was 49.33 dmm. Clearly, this value falls within the grade 44-60. This contradicts the specification of shell bitumen (2003) which suggests that it should be grade 20-30. Softening Point Test In table 1.2, the two temperatures for bitumen softening point and the average value for the two tests is demonstrated. Table 1.2 Results for Softening point temperature results Temperature (ºC) Mean Ball 1 62 61.5 Ball 2 61 Table 1.2 indicates shows that measured temperature when the ball began to fall were 61ºC and 62ºC. These two average to 61.5ºC, which is the softening point temperature for the bitumen sample tested. Viscosity (s) 213 Table 1.3: Results of Viscosity of a sample of cutback bitumen Table 1.3 shows that the viscosity of a sample cutback bitumen as obtained in this experiment was 213. Koole and Thagesen (2004) noted that the penetration index (Pi) represents variations of penetration depth and the bitumen sample’s softening point temperature. PI value can also be evaluated through noting the penetration at 2 different testing temperatures or with the use of penetration at one temperature. In this case, the penetration depth was 49.33dmm. The softening point in this experiment was found to be 61.5 degrees. The nomograph as provided in figure 1.1 enables PI to be approximately deduced from a penetration at 49.33 dmm and the softening point temperature of 61. 5 degrees Celsius. Figure 1.1 shows that using a penetration value of 49.33 dmm and a softening temperature of 61.5 degrees Celsius. The penetration index of 1.2 SP/Pen was found for tested bitumen sample. Figure 1.2 Penetration Index of bitumen sample Discussion It is a requirement for road pavements to utilise the available resources in order to ensure roads are well developed and are of economic value. There are a number of pavement material including rocks, soils, cement and lime. Before utilizing properties of some material it is important for one to ensure he or she becomes aware with the properties and property variations of these materials. The change of these properties can considerably affect both the stability and durability. Penetration of bituminous material is the method more often used in measuring the consistency of bituminous materials at a certain temperature. The method is a means of classification. In engineering the term consistency refers to the measure of resistance generated by a fluid against continuous deformation after being subjected to shearing stress. It is a function of the bitumen’s chemical constituents, Vis the relative proportion of resins, asphaltenes, and oils. The amount and type of the constituents of bitumen are determined by the method of processing and source petroleum. Viscosity and penetration are related. Basing on this relationship, empirical relationships were developed for those material that obey Newton laws of physics. It is possible to establish temperature susceptibility of bitumen through measuring penetration for a given range of temperatures. Consistency of bitumen and temperature changes may be related by an expression below: log P = AT + K where A = temperature susceptibility (or temperature sensitivity) P = penetration at temperature (T) K = constant A penetration Index (PI) was defined upon which temperature susceptibility assumes a value zero for the road bitumen as provided by PI=  …………………………………………………..(3) The value of PI (A) can be derived from the penetration measurements at temperatures T1 and T2. Using the equation A  ……………………………………(4) Studies indicate that for the conventional paving grade bitumen, the Ring-and-Ball Softening Point temperatures is equal to the temperature that gives the penetration of 800 d-mm. This along with the penetration at a temperature of 25 degrees Celsius can be applied in the computation of A where Using the equation A= ……………(5) In this study, equations 3 and 5 were used to calculate the temperature susceptibility of bitumen (A) and penetration index (PI). These were calculated from measured penetrations and softening point temperatures. The penetration distance found in the experiment clearly indicate a reduction of the in the depth of penetration of the needle with consequent testing. This can be related to alterations in the temperatures around the test bench which alters the viscosity of bitumen. The results of the study show that the mean of the penetration depth was 61.5 dmm for the tested sample of bitumen. This indicates a higher hardness of a tested bitumen. Based on the bitumen specifications, increase in the penetration depth causes the bitumen sample to be softer. However, there is need for further guidance because maximum differences between the lowest and highest penetration depth leads to (49.33 and 61.5dmm, table 1.1), is not As shown in bitumen specifications, as the penetration value increases, the bitumen sample becomes softer. As observed in this experiment the maximum difference between the highest and the lowest penetration value results (47 and 52 dmm, see Table 1.1) is not within the range that was specified by BS2000: Part 49. BS2000: Part 49 indicate that that the three determinants of penetration depth should not exceed 4 dmm for penetration up to 149. This was not the case in this study as the difference is 5dmm. With regard to the applicability of dependence of bitumen materials on the penetration grade, it was revealed that the grade and the utilization and composition of bitumen are directly related. This implies that bitumen that has high penetration can be used in cold environment pavements. This help prevent problems related to cracking of pavements under low temperature conditions. The bitumen with higher penetration values such as the bitumen type that was tested in this study can be applicable in countries with hot weather. This is also can be assisted by the possibility of the lower penetration bitumen to give stability when it is mixed with high sand contents. This type can find its applications at the roads with higher traffic stresses including the bus stops. It can be seen in winter in the UK streets some cracks to the roads, which is mainly because the inappropriate grade bitumen is used or the temperature drops to the values affected the bitumen properties. As demonstrated in Table 1.1, the average value of 61.5 decrease Celsius was found to be for bitumen softening point temperature. On the other hand, the test for needle penetration demonstrated the tested bitumen sample to be 44-60 grades. The specification for bitumen indicate that the grade of the softening point lies within the 55 to 63ºC range. This strong match, as revealed in this study show that results of the average softening point temperature well the temperature range specified for 20/30 bitumen grade. However, the records of the softening point temperature have difference of 0.4 degrees compared with the two temperature records. The difference has to be 0.2 degrees; therefore, there could be some source of error in measuring the temperature. This error can be reduced by repeating the experiments after doing the required calibration to the measuring devices. Conclusion In this lab, bitumen material was used to evaluate the value of the penetration of the needle alongside the softening temperature and the Index. For the needle penetration, a test was conducted thrice under standard time, temperature and load conditions. It was revealed that the average value for depth penetration was 49.33 dmm. This value indicated that the tested bitumen was 40/50 grade. This shows that the sample is naturally hard. It can therefore, be applicable in countries with cold climate. To determine bitumen softening point temperature, two tests were conducted. The average value of the two tests was found to be 61.5 degrees, which fails to match the temperatures specified for the 40/50 bitumen grade specifications. The results, however, show a difference, between lowest and highest average temperatures, greater than 0.2 degrees. This can be attributed to an error in the measurement of temperature. This can be avoided by re-test the sample and making fine calibration on the temperature measuring equipment. References Brennan, M. J. and O’Flaherty, C. A. (2002). Materials used in road pavements. In: C.A. O’Flaherty (Ed.). Highways: The location, design, construction and maintenance of road pavements. 4th edition, Butterworth-Heinemann, Oxford, UK. Retrieved on 7th April, 2014 from http://books.google.co.tz/books/about/Bitumen_and_Bituminous_Binders_Determina.html?id=pzA-GQAACAAJ Koole, R. and Thagesen, B., (2004). Asphalt Pavement Materials. In: Roberson, R., and Thagesen, B. (eds), Road Engineering For Development. 2nd edition, Spon Press, London. Retrieved on 7th April 2014 from http://www.lavoisier.fr/livre/notice.asp?ouvrage=1302429 Shell bitumen (2003) “Shell Bitumen Handbook” Shell bitumen UK, London. BS2000: Part 49: 2007. Bitumen and bituminous binders — Determination of needle penetration. British Standards Institution, London. BS2000: Part 58: 2007. Bitumen and bituminous binders — Determination of the softening point — Ring and Ball method. British Standards Institution,London. Appendix A Raw Data and Calculations Table A.1 Penetration Measurements (dmm) Sample 1st test 2nd test 3rd test Average 4B16 47 49 52 49.3 Table A.2 Softening Point Temperature Measurements Temperature (ºC) Mean (ºC) Ball 1 61 61.5 Ball 2 62 Appendix B Safe Working Procedure A. PRIOR TO STARTING WORK I. Ensure everybody is aware of safety procedures in case of emergency II. Check equipment for purposes of safety and operation III. Each student must review the test procedures before he/she starts the tests IV. Each student must be dressed in lab coats and safety boots during experiments. V. Each student must know the safety measures when using test tools B. Whilst Undertaking the LABORATORY WORK I. Ensure there are no spills of bitumen or water II. Check to ensure hands are dry before starting to use electrical equipment III. Ensure the penetrating needle is cleaned gently and safely IV. During the softening experiment watch the water heating carefully V. Pay attention to hot water spills C. PRIOR TO DEPARTURE of the laboratory session I. Ensure the electric source remains switched off II. Ensure the set of equipment and tools are safely positioned III. Check and ensure there are no spills of bitumen and water IV. Ensure the fine equipment are kept in their required position V. The bench must be cleaned D. RESPONSIBILITIES Washing hands and other issues I. Immediately reporting of an incident to the lab technicians II. Not to damaging or playing with equipment not required for the test III. The lab must be kept quiet IV. The placed must be kept clean and tidy Appendix C RISK ASSESSMENT FORM Task - Hazards/Deficiencies Risk Current Controls Remedial Measures; Controls, Action; Comments. (including action date) WCO LIK LVL Benzene inhaling during needle cleaning min medium low Wear protective masks Training courses on safety are required Hands burn with hot water min medium low Users are reminded of wearing gloves Training courses on safety are required Electric shock max low high Cut the electricity Regular checks of electrical appliances Fire occurrence max law high Use fire extinguisher Clear the lab through fire doors Hands injury in needle penetrating min medium law Use suitable gloves and penetrate gently Training courses on safety are required Bitumen spillage min medium law Use cleaning cloth and wipes Training courses on safety are required Read More