Investigation of the Properties of “Pure Water” Sachet Modified Bitumen

Abstract

The increasing volume of traffic loads on our roads is currently a challenge on flexible pavement design and construction.  Factors such as durability, strength and economic needs have to be considered in the design and construction of road pavement.  Many researches have been conducted to explore supplementary material that can make a durable asphalt pavement.

It is not unfamiliar that the modification of bitumen with the use of polymers enhances its performance characteristics but at the same time significantly alters its rheological properties.

One of the environmental issues in most regions of Nigeria is the large number of polymeric wastes made from polyethylene water sachet (PWS) popularly called “Pure Water” Nylon deposited in domestic wastes and landfills.

This study was conducted to investigate the effect of PWS on the properties of conventional bitumen and suitability of discarded PWS as bitumen modifier and to reduce the environmental effects of PWS disposal.  Bituminous blends containing PWS at various percentages 2.5%, 5%, 7.5%, 10%, 12.5% and 15% weight of conventional bitumen.

Penetration, softening point and float tests were carried out on the samples to evaluate the penetration index, viscosity, stiffness modulus and the suitability of PWS as bitumen modifier. Sieve analysis and infrared spectroscopy of the shredded PWS sample were also carried out. Result obtained from tests was compared between control sample (0% PWS) and PWS modified samples.

The test results show that PWSs influence more on the penetration of the modified sample with the increase in the viscosity of the bitumen as can be observed by the decrease in the value of penetration with the increase in concentration of PWS. The penetration index values of Samples 2.5% PWS and 7.5% PWS makes them to be classified as blown bitumen and the PI value of Sample 5% PWS makes it less susceptible to temperature changes and can be classified as oxidized bitumen.

PWS is a cheap and readily available material in construction when used appropriately in bitumen and the recycling of PWS for asphalt base roads helps alleviate an environmental problem and saves energy.

Keywords: Bitumen, pure water sachet (PWS), infrared spectroscopy analysis, penetration test, softening point, viscosity test