The present work investigated the properties of the commonly used Butimen for road construction in Nigeria (60/70 pen.) for normal temperature and climate Effect. The laboratory tests conducted were penetration, softening point, viscosity, ductility test and flash and fire point test based on the ASTM standards. The result indicates a decrease in stiffness of bitumen with an increase in temperature, with a decrease in penetration of bitumen by 85.5% when tested between 25°C to 43.2°C and also the Ductility decreases with increase in temperature by 54.9% between 25°C and 43.2°C. The viscosity result shows a decrease in viscosity with an increase in temperature, therefore at higher temperature Bitumen is likely to flow.
Bitumen is an engineering material and is produced to meets variety of specifications based upon physical properties, it is the residual product from distillation of crude oil.Eurobitume, A. I. (2011) [
Several road pavements distresses are related to bitumen properties. Rutting and fatigue cracking is the major distresses that lead to permanent failures in pavement construction. Bitumen is a viscoelastic material; its rheological properties are very sensitive to climate change (temperature and water/snow) and rate of loading (Ali, Nuha, and Mohammed (2013) [
Since the signing of Kyoto protocol to limit global warming, climate change impact has been in the forefront of international Discuss. Even though climate change is a global phenomenan, its impact must be evaluated for specific systems, areas or regions kyoto protocol report (1998) [
Collier, Conway, and Venables, 2008 [
Many researches have been carried in the area of modification of bitumen to enhance its stiffness. As such, there is a need for studies to be conducted on the reason why asphalt pavement fails, which is mostly characterized by rutting and fatique cracking.
This primary objective of this research is to investigate the effect of climate change on the rheological properties of bitumen. The secondary objective is to determine the extent of climate change in the study area and to explore the use of appropriate penetration grade bitumen for use as a climent resilient material and also to analyse the implication for road maintenance.
Since the main aim of this research is to see the influence of climate parameters on the rheological properties of bitumen, the first step is to obtain climate data over a period of time and to analyse them to see whether climate has a bearing on bitumen. Two climate parameters i.e. (Temperature and Rainfall) were collected for 77 years and 103 years respectively and statistically analysed in trenches of thirty (30) years. This is because thirty (30) years is the average weather condition.
The sample bitumen (60/70) Penetration grade was obtained from Dantata and Sawoe asphalt plant, this binder has been commonly been used in Nigeria. The softening point, flash and fire point test, pentration test, viscosity test, and ductility test were all conducted as per American Standard for Testing Material (ASTM).
To achieve the aim and objective of this research, a temperature of 1.4˚C was increment to the ambient temperature of 25˚C upto 43.2˚C to conduct penetration test and ductility test. For viscosity 1.4˚C is incremented to 55˚C up to 73.2˚C because viscosity cannot be conducted at a temperature lower than softening point of the (60/70) penetration grade bitumen of 54.5˚C. The result obtained for penetration, ductility and viscosity were computed and analysed as shown in
Temperature records obtained are analysed in trenches of thirty (30) years as shown in Figures 1-3. In
Test type | Test standards |
---|---|
Softening point test | ASTM d-36 standard |
Flash and fire Point test | ASTM d-9218 standard |
Penetration apparatus | ASTM d-5 standard |
Viscosity test | ASTM d-2170 standard |
Ductility test | ASTM d-113 -99 standard |
Under Normal Distribution | 1 | 2 | 3 |
---|---|---|---|
Skewness | −0.65173 | 0.21892 | −0.62852 |
Excess kurtosis | 3.7768 | −0.30439 | −1.0044 |
From
Under Normal Distribution | 1 | 2 | 3 | 4 |
---|---|---|---|---|
Skewness | 1.4053 | 1.568 | 1.8492 | 1.4053 |
Excess kurtosis | 0.94431 | 1.7235 | 2.9398 | 0.94431 |
The average flash and fire points are 148˚C and 279˚C respectively as seen in
N/0 | Flash point (˚C) | Fire point (˚C) |
---|---|---|
1 | 148 | 280 |
2 | 147 | 285 |
3 | 149 | 272 |
AVERAGE | 148 | 279 |
The average softening point of the samples used is 54.5˚C as shown in
Furthermore, the increment of 1.4˚C on the sample up to 43.2˚C is still lower than the softening point by 20.73%. Thus the softening point is not likely to be adversely effected by climate change.
The penetration test is a measure of the hardness of bitumen ASTM D-2179 standard [
The ductility of bitumen material is the distance in centimeters to which it will elongate before breaking when a briquette specimen of the materials is pulled at a specified speed and at specified temperature in the simplest definition is a measure of the tensile strength of bitumen ASTM D113-99 standard [
Softening Point | |||
---|---|---|---|
1 (˚C) | 2(˚C) | Average (˚C) | |
54 | 55 | 54.5 |
Temperature | 1 | 2 | 3 | Average (mm) |
---|---|---|---|---|
25 | 57 | 65 | 60 | 60.67 |
26.4 | 72 | 85 | 80 | 79 |
27.8 | 88 | 76 | 80 | 81.30 |
29.2 | 84 | 120 | 105 | 100.00 |
30.6 | 126 | 87 | 91 | 101.30 |
32 | 165 | 146 | 140 | 150.30 |
33.4 | 176 | 194 | 158 | 176 |
34.8 | 207 | 196 | 196 | 199.67 |
36.2 | 248 | 230 | 246 | 241.30 |
37.6 | 244 | 252 | 238 | 244.67 |
39 | 256 | 255 | 246 | 252.30 |
40.4 | 275 | 308 | 300 | 294.30 |
41.8 | 326 | 317 | 316 | 319. 67 |
43.2 | 355 | 343 | 314 | 337.30 |
Temperature | 1 | 2 | 3 | Average (cm) |
---|---|---|---|---|
25 | 100 | 100 | 100 | 100 |
26.4 | 78 | 78.5 | 78 | 78.20 |
27.8 | 69 | 69 | 68 | 68.67 |
29.2 | 53 | 54 | 54 | 53.67 |
30.6 | 50 | 51 | 49 | 50 |
32 | 48 | 47.5 | 47.5 | 47.67 |
33.4 | 46 | 46 | 47 | 46.30 |
34.8 | 46 | 46 | 46 | 46.00 |
36.2 | 45 | 45.5 | 45 | 45.20 |
37.6 | 44.5 | 44.5 | 45 | 44.67 |
39 | 44.5 | 44.5 | 44.5 | 44.5 |
40.4 | 44 | 44 | 44 | 44 |
41.8 | 44 | 44 | 45 | 44.30 |
43.2 | 43 | 43 | 42 | 42.67 |
and the mean temperature of 33.49˚C is 53.7% with (53.7 cm) while the difference in ductility between the ambient and the maximum temperature recorded, 41˚C is 54.9% i.e. (44.1 cm). This is important because any change in temperature could lead bitumen to fail in tension. This can accentuate fatique cracking of pavement and consequently their failure (
Asphalt pavements are laid at a high temperature of about 160˚C ASTM D-2179 standard [
Temperature | Seconds |
---|---|
55 | 370 |
56.4 | 360 |
57.8 | 189 |
59.2 | 120 |
60.6 | 79 |
62 | 74 |
63.4 | 69 |
64.8 | 64 |
66.2 | 58 |
67.6 | 54 |
69 | 52 |
70.4 | 52 |
71.8 | 48 |
73.2 | 46 |
The correlation between climate change and rheology of (60/70) penetration grade bitumen has been known. Nevertheless, the test condition needs to be further investigated in the future in order to get a correlation for all types of binders.
The (60/70) penetration grade bitumen is likely to flow under high, as such, there is a need for further research to be investigated on suitable materials that is low interms sustainability to climate change to modify our bitumen for more durability and to enhance stiffness of (60/70) grade bitumen.
The Authors wish to acknowledge Management and technical staff of Bayero University, Ahmad Bellow University Zaria for their technical support and Metrological Agency Kano for their support with relevant information and records.
The authors declare no conflicts of interest regarding the publication of this paper.
Abdulkadir, I. and Alhasssan, H.M. (2020) Impact of Climate Change on Rheological Properties of Bitumen. Open Journal of Civil Engineering, 10, 93-104. https://doi.org/10.4236/ojce.2020.102009