The influence of waste cooking oil (WCO) on the performance characteristics of asphaltic materials indigenous to Trinidad, namely, Trinidad Lake Asphalt (TLA), Trinidad Petroleum Bitumen (TPB), and TLA : TPB (50 : 50) blend, was investigated to deduce the applicability of the WCO as a performance enhancer for the base asphalt. The rheological properties of complex modulus (G ∗) and phase angle (δ) were measured for modified base asphalt blends containing up to 10% WCO. The results of rheology studies demonstrated that the incremental addition of WCO to the three parent binders resulted in incremental decreases in the rutting resistance (decrease in G ∗/sinδ values) and increases in the fatigue cracking resistance (decrease in G ∗sinδ value). The fatigue cracking resistance and rutting resistance for the TLA : TPB (50 : 50) blends were between those of the blends containing pure TLA and TPB. As operating temperature increased, an increase in the resistance to fatigue cracking and a decrease in the rutting resistance were observed for all of the WCO modified asphaltic blends. This study demonstrated the capability to create customized asphalt-WCO blends to suit special applications and highlights the potential for WCO to be used as an environmentally attractive option for improving the use of Trinidad asphaltic materials.

The improper disposal of used frying oil (UFO) presents numerous ecological, environmental and municipal problems. Of great concern is the resultant blockage of municipal drainage systems and water treatment facilities, harm to wildlife when they become coated in it and detriment to aquatic life and ecosystems due to the depletion of the oxygen content in water bodies such as rivers and lakes that have become contaminated. Statistics show that in Trinidad and Tobago, in excess of one million liters of used cooking oil is collected annually from various restaurant chains. This paper investigated the potential of using UFO as a performance enhancing additive for road paving applications utilizing Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) as a mitigation strategy for improper UFO disposal. Modified blends containing various additions of UFO (2–10% wt) were prepared for the TLA and TPB asphaltic binders. Results demonstrated in terms of stiffness, increasing the dosage of UFO in TLA and TPB base binders resulted in a gradual decrease in stiffness (G* value decreased). In terms of elasticity, increasing the dosage of the UFO additive in TLA resulted in a general decrease in the elasticity of the blends indicated by an increase in phase angle or phase lag (δ). Increasing dosages of the UFO additive in TPB resulted in a significant decrease in δ where the most elastic blend was at the 6% UFO level. TLA and UFO-TLA modified blends exhibited significantly lower values of δ and higher values of G* confirming the superiority of the TLA material. Incorporation of the UFO in the blends led to a decrease in the rutting resistance and increase in the fatigue cracking resistance (decrease in G*/sinδ and G*sinδ, respectively). This study highlighted the potential for the reuse of UFO as an asphalt modifier capable of producing customized UFO modified asphaltic blends for special applications and confirms its feasibility as an environmentally attractive means of reusing the waste/hazardous UFO material locally.

This paper investigates the influence of Waste Cooking Oil (WCO) on the rheological properties of three Trinidad asphaltic base binders: Trinidad Lake Asphalt (TLA), Trinidad Petroleum Bitumen (TPB) and a TLA:TPB (50:50) mixture. The addition of WCO to the asphaltic base binders resulted in changes in the rheological properties as demonstrated by changes in the phase angle, δ (elasticity) and the complex modulus, G* (stiffness) of the blends. The intricate relationship between the chemical composition of the binder and the influence of the WCO was evident as changes in δ and G* due to the addition of WCO was not generalized and were different for each of the asphaltic base binder. The incremental addition of WCO into the three asphaltic binders resulted in the softening of the material (decrease in the G*). Incremental addition of WCO into the TLA asphaltic binder resulted in an incremental decrease in elasticity (maximum δ at 6% WCO), however minimum values of δ were observed (highest elasticity) at 8% WCO for TPB and at 2% WCO for the TLA:TPB (50:50) base blend, the latter blend being the most elastic with a phase angle (δ) of 20.5 degrees. This value of 20.5 degrees was far lower than that of TLA (73%) under identical testing conditions. In all cases G″ > G' indicating viscoelastic liquid behavior for the base asphalts and its blends. The study demonstrated the capability to create customized asphalt-WCO blends to suit special applications by formulating specific quantities of Trinidad base asphalts and WCO thus offering an environmentally attractive option for improving the use of asphalt.

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The influence of added coir (coconut) fibre of various lengths (from 2.5 mm to 10 mm) and dosages (up to 8 wt%) on the rheological properties of Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) was evaluated by measuring changes in the phase angle, δ (measure of the elasticity) and the complex modulus, G* (measure of the degree of stiffness). Results indicated that for both TLA and TPB, the highest values of G* (stiffest) and the lowest values of δ (most elastic) were observed for blends containing 2.5-mm coir fibre lengths for added coir concentrations of 6% and 8%, respectively. When compared to the unmodified TLA, the addition of 6 wt% of 2.5-mm coir fibre resulted in the largest significant increase in G* (7.3 times) as well as a significant decrease in δ (from 49.3° to 19.8°), representing a significant stiffening and increased elasticity of the modified blend. For TPB, the optimum concentration of added coir fibre occurred after the addition of 6 wt% of the 2.5-mm coir fibre, which resulted in the largest significant increase in G* of 5.4 times (stiffening) as well as a significant decrease in δ from 86.2° to 47.4° (increased elasticity as the material transformed from an almost viscous liquid to a semi-elastic solid) when compared to the unmodified pure TPB. The utilization of coir fibre for the rheological enhancement of Trinidad asphaltic materials can also provide an environmentally attractive option for solving the waste disposal issues associated with the dumping of waste coconut husk.