LIFE EXPECTANCY OF RECYCLED ASPHALT PAVING

In 1929, three types of failure occurred in large areas of asphalt surfacing in Singapore. Research undertaken in 1930 to 1931 at the University of London, appeared to indicate the causes. The problem was not only that of preparing revised specifications but that of finding economical means of maintaining the failed surfacings. Recycling was found to be possible in each case, and the recycled material had a life of from 25 to 30 years. In 1947, a contracting company was formed in Bombay, India, for recycling defective asphalt surfacings in that city, and contracts for such work have continued to be placed with the company. Many of the surfaces treated in the first contract are still serviceable while some have been recycled for the second time. Only minor modifications of mixing plant are used and no proprietary additives were found to be necessary. Success depends entirely on effective laboratory control, and the life expectancy of a recycled asphalt surfacing need be no less than that of a surfacing prepared from entirely new materials. (Author)