The asphalt industry has been perpetually challenged with its health hazardous emissions and global warming issues, especially when produced with or from derivatives of fossil fuels and together with the need for higher strength to meet the heavy truck axle loads on highways. In view of the steady increase in high traffic intensity of heavily loaded trucks and the increase in the overloading of truck axles together with the significant variation in daily and seasonal temperature due to climate change effects, it is essential to modify the conventional asphalt cement using a combination of modifiers to improve the engineering properties of mixes to meet the complexity of the factors for higher strength and the environment. Global warming has consequently contributed immensely to adverse climate change effects, environmental degradation and attendant human health problems. The challenges posed by global pollution and depletion of fossil fuels leading to high cost of bituminous binder derivatives such as bitumen have motivated the search for and development and utilization of alternative binders, amongst which are polymer-modified bitumen and bio-oils. Research in this direction is hoping to find a permanent replacement for bitumen, thereby reducing greenhouse gas emissions and attendant climate change effects.
Part of the book: Asphalt and Asphalt Mixtures