A Cost Effective Solution for Repair and Resurfacing of Distressed Asphalt Pavement by Coating of Ultra-Thin Whitetopping

Abstract

Fly ash, a waste derived from coal burning in thermal power plants is bounteous in India
causing severe health, environment and dumping problems. Now days, it is estimated that about 150
million tons of fly ash are being produced from various thermal power plants in India. Utilization of
fly ash in bulk quantities, ways and means is being discovered all over the world to use it for the
construction of embankments and pavements. This way the fly ash concrete are made a 'greener'
building material and the discarded natural wastes can be re-utilized, avoiding otherwise wasteful
landfill and harmful open incineration. To make value added concrete for development of sustainable
infrastructure there is a great need to study the technical details concerned with various industrial
wastes in concrete and to reduce environmental hazards. The significant increase in the number of
automobiles observed in the recent years has created a need not only for the construction of new
highways but also for the maintenance and rehabilitation of existing highway networks. Pavements
are prone to damage due to the repeated wheel loads as well as temperature and other environmental
effects. Ultra-thin white topping (UTWT) / thin white topping (TWT) is a technique which involves
placement of a thinner (than normal) thickness ranging from 2 to 4 /4 to8 inches with closely spaced
joints and bonded to an existing asphalt pavement. The application of UTWT/TWT has been targeted
to rehabilitate deteriorated asphalt pavements with fatigue and/or rutting distress. However the actual
depth of UTWT/TWT depends on the grade of concrete used, intensity of traffic, thickness of
existing asphalt pavement after milling etc. So our study is concerned with eco-efficient utilization of
Fly Ash (F-class) as partial replacement of cement in concrete. The aim of the present study is to
investigate the low cost UTWT/TWT made of fly ash (F-class). The fly ash (F-class) was replaced
within the range of 10-40% by weight of cement. In the present study, 5 different mixes of fly ash
concretes are tested for parameters like: compressive strength, flexural strength, modulus of elasticity
and cost.