Characteristics of asphalt modified with industrial waste sludge containing calcium carbonate

Abstract

In today s era, bituminous mixes are often used in pavement construction globally. Design of these pavements is a multi-step process of choosing binders and aggregate materials and quantifying them to provide a suitable mix taking into the effect of external factors such as traffic loading and climatic conditions. As the traffic intensity is exponentially increasing and the variation in temperature is rising, the need to think of an alternative solution for improvement of pavement characteristics has cropped up. These problems have a damaging effect on the preferred properties of bituminous pavement, such as flexibility, resistance to fatigue, resistance to rutting and raveling. It is caused by gradual build-up of irrecoverable strains under repeated loading, which develop into a measurable rut (permanent depression along the wheel path). These strains are due to the visco-elastic response of bituminous materials to dynamic loading. Unmodified bitumen lacks the balance between the visco-elastic response and the increase of the traffic volume. Therefore, binders were modified to face the load and weather challenges. Modified bitumen introduces advantages to the field of highway construction, by improving pavement performance as well as extending the pavement life. Recently, numerous waste materials have resulted from manufacturing operations, service industries and household in which several millions of non-biodegradables are produced. If not taken care of, they will persist in the same state for a considerable time and thus causes hazardous problems to environment and human life. One such solution to this problem is the use of modified bitumen that satisfies both the strength and economic aspect. The generation of large quantities of wastes is a result of rapid industrialization and we are lagging in the process of using it effectively. It creates environmental and ecological problems apart from occupying large tracts of valuable cultivable land.