Utilisation of warm-mix asphalt technology to improve bituminous mixtures containing reclaimed asphalt pavement

摘要

Pavement recycling is a logical way to conserve our diminishing supply of construction materials and reduce the cost of preserving our existing pavement. In this research road recycling was discussed briefly through a number of lab tests using Marshall test, Indirect Tensile (IDT) test and Loaded Wheel Track Rutting (LWTR) test on Reclaimed Asphalt Pavement (RAP). These tests were conducted to justify the properties and analyse the strength of RAP mixtures containing Sasobit material, which is considered a Warm-mix Asphalt Wax (WMAW) to improve the characteristics of the mix, and reduce the standard viscosity temperature, bitumen amount and compaction temperature. The study used bitumen penetration grade (PG) (60/70) produced by local Sues factories. The bituminous layer used was the wearing surface layer. Samples for RAP were taken from Cairo-Fayoum desert road. The virgin materials were gathered and tested according to Egyptian specifications. To achieve this goal, several samples were considered for Marshall test and IDT test using different ratios of RAP (15%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 100%) with different amounts of WMAW (1.5% and 3%) and taking different compaction temperatures (115, 125 and 135 degrees C). As for the LWTR test, the samples were made with 15%, 20%, 60% and 80% RAP. The results were compared to the standard mix (no WMAW at 135 degrees C compaction temperature). Laboratory results showed that the use of RAP with WMAW resulted in improvement in compactability, increase in the softening point, reduction in penetration and increase in resistance to rutting. In addition, Analysis of Variance (ANOVA) using SPSS software was also used to compare the means of results for stability and air voids of Marshall test, IDT test and LWTR test to that of the standard mix. The ANOVA analysis showed significance in results when using the WMAW, and the most significant results were obtained when using 1.5% WMAW additive at a temperature of 125 degrees C with 20% RAP mixture.