The present work investigated the properties of the commonly used Rheological Properties for road construction in Nigeria (60/70 pen.) for normal temperature and climate Effect. The laboratory tests Rheological Properties 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) [1]. Bitumen has been widely used in Nigeria for the construction of flexible pavements for more than a century. Flexible pavements with bituminous surfacing are widely used all over the world. It has been well known and used since 6000 BC as a waterproofing and binder material of great quality. The Sumerians used it in the prosperous shipbuilding industry, whereas the Babylonians used it as a binder in the mixture production for castle construction (Babel Tower) [2]. Asphalt was also used by the Egyptians both to mummify the dead bodies and to waterproof tanks. Around 3000 BC, the Persians also used bitumen for road construction.

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) [3]). The resistance to rutting of asphalt surfacing depends on road temperature as well as traffic load. At high temperature, asphalt becomes more susceptible to deformation, and rutting is more likely to occur, particularly on highly trafficked roads and at low traffic speeds. Research has found that the majority of rutting in asphalt surfacing occurs on a few days of the year, when the temperature of the road surfacing exceed 45˚C (Willway, and Reeves (2008) [4]). In general, road pavement performance properties are mainly affected by the bitumen binder properties.

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) [5]. In Transportation, climate change impacts are manifested in pavement production and vehicle operation. The effort to migitate the impact includes the use of clean energy and the use of innovative materials and technology to lower the production and operating temperatures of ashphalt. The properties of bitumen are heavily dependent on temperatures and to some extent on the exposure of bitumen to water. Unless efforts are made to curtail global warming, the performance of bitumen under varying temperature regimes might adversely affect the life span of flexible pavements. Rutting, revelling and cracking are the main distress features caused by the temperature gradient in asphalts; climate change can aggravate these. Rutting in asphalts develops gradually with increasing number of loads applicationSousa, et al 1991 [6].

Collier, Conway, and Venables, 2008 [7]: Gemeda and Sima 2015 [8] reports on regional climate projection of 2007 state that by 2050 the average temperature in African continent is expected to rise by 1.5˚C – 3˚C and, warming of Africa is very likely to be severe than other regions. Asphalt institute 2011 finds that Changes in temperature alters the Physical properties of Bitumen. Temperature across Africa is expected to rise by 2 – 6 within the next 100 years and rainfall variability is also expected to increase, resulting in regular flooding EA, A. 2018 [9]. Qiang Li, et al., 2011 [10] conclude that quantity and intensity of precipitation, in the form of rain and snow, affects the quantity of surface water infiltrating into the subgrade and the depth of groundwater table, Poor drainage may reduce shear strength, or cause pumping or loss of support. Moisture (in the form accumulated water or rainfall) affects pavements in several phases of the pavement life cycle: Ab Rahim 2012 [11] studying on aging process of polymer modified Bitumen finds the bitumen plays a large part in determining many aspects of road performance because of their good adhesion to mineral aggregate and their physical properties.

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.