Impact of Rainwater on Bituminous Road Surfacing

Abstract

Accumulation of rainwater on roads due to lack of proper drainage causes loss of adhesive bond between bitumen and aggregate which results into stripping and severe damage to the pavement. Indian Standard (IS 6241-1971: method of test for determination of stripping value of road aggregate. Laboratory test, 1971) [1] prescribes the stripping test in which aggregate coated with bitumen is kept immersed in water for 24 h at 40 °C. After the test, the retained coating of bitumen should be minimum 95% for the aggregate to be suitable for road construction. Most of the time, the aggregate exhibits no stripping under laboratory conditions, whereas it fails in stripping under field conditions. To understand this problem, a laboratory investigation was conducted on the aggregate of Haryana taking into consideration some of the prevailing field conditions like acidic/alkaline nature of water and the presence of traffic on the roads. The test results indicated that the pH of water and application of external pressure affected the stripping considerably.