Performance of Waste Polymer Modified Road Paving Materials

Abstract

The reuse of waste crumb rubber (CR) (used tyres) and Polyethylene Terephthalate (PET) (plastic beverage bottles) is of particular interest in Trinidad and Tobago since present disposal techniques presents environmental and health challenges. The results of this study investigating the influence of PET and CR on the performance characteristics of the HMA2 pavement design using Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) filled an information gap as no previous studies utilizing these indigenous asphaltic materials exist. Existing information using asphaltic materials other than TLA and TPB are irrelevant as variations in performance characteristics due to the addition of polymeric additives can vary from asphalt to asphalt due to differences in source and chemical composition of the parent binder. The results of this study show that a 6% CR and PET addition achieved the highest performance advantage demonstrated by an increase in the Marshall Quotient of between 21–22% and an insignificant decrease in the Bulk Specific Gravity (0.2%) compared to the unmodified blend. The improvement in the mechanical properties and the performance of the modified pavement materials observed is evidence of the useful effects of these waste materials in road paving design and offer a beneficial strategy for the reuse of these waste materials.

The performance and durability of polyethylene terephthalate and crumb rubber–modified road pavement surfaces

“…16 The use of waste polymeric wastes to possibly improve asphalt pavement performance while simultaneously solving the environmental problem associated with disposal has been receiving research attention with encouraging results in Trinidad and Tobago. 3,5,17 -21…”

“…Similarly for rutting resistance, the optimum particle size and CR addition for TLA was between 250 µm and 355 µm at 4% CR addition and between 500 µm and 710 µm at 5% CR addition for TPB. 3…”

“…Trinidad Lake Asphalt (TLA) is obtained from the Pitch Lake located in the southwestern part of Trinidad and basically comprises a mixture of bitumen, water and very fine mineral matter. 3 TLA has been internationally well established as a commercial product and a source of superior quality asphalt (due to its consistent properties, resistance to cracking, stability and durability compared to other asphaltic materials) and is often specified as a mandatory ingredient for paving in high demand situations such as those encountered in airport runways. [4][5][6] Research has shown that the unique fractional, chemical and functional group composition of TLA determines its strength, durability and resistance to ageing and weathering.…”

“…[4][5][6] Research has shown that the unique fractional, chemical and functional group composition of TLA determines its strength, durability and resistance to ageing and weathering. 2,3 Asphalt's most valuable and widespread usage is for that of paving. 7 The fractionation compositions of TLA and TPB compared to other materials from other sources are illustrated in Figure 1.…”

“…16 The use of waste polymeric wastes to possibly improve asphalt pavement performance while simultaneously solving the environmental problem associated with disposal has been receiving research attention with encouraging results in Trinidad and Tobago. 3,5,[17][18][19][20][21] A serious issue of national importance in Trinidad and Tobago in recent times has been the uncontrollable usage and disposal of crumb rubber (CR) from used vehicle tyres and polyethylene terephthalate (PET) from beverage containers. An article in the Trinidad Express Newspapers on 1 October 2013 stated that Trinidad and Tobago was on the verge of licensing the country's millionth car.…”