Impact of bitumen and aggregate composition on stripping in bituminous mixtures

Abstract

The impact of bitumen and aggregate composition on stripping was investigated using four bitumens and four aggregates. Moisture sensitivity was assessed based on retained resilient modulus and tensile strength ratio (MRR and TSR, respectively). The results indicate that mixtures from the bitumen with a high acid number exhibited high resilient modulus and tensile strength in the dry condition for all the aggregates. In wet condition, this conclusion did also hold except for one aggregate. Regarding penetration grade, mixtures made with lower penetration grade bitumen exhibited higher resilient modulus and tensile strength, in dry and wet conditions, than those of higher penetration grade. Bitumen characteristics like acid number, penetration grade and molecular size distribution did not influence moisture sensitivity. Mixtures with aggregates containing alkali metals (sodium and potassium) exhibited relatively high moisture sensitivity, regardless of the bitumen used. In contrast, indications of moisture sensitivity were not apparent in mixtures made with aggregates containing calcium, magnesium and iron. Data analysis revealed that variability in moisture sensitivity is attributed to aggregate rather than bitumen. No significant interaction effect between bitumen and aggregate was found on moisture sensitivity.

Wetting Model of Asphalt on the Aggregate Surface and Its Effect Factors

“…e surface tension of the liquid is caused by its surface molecules suffering unbalanced force, and usually varied with the temperature [21]. According to the surface tension experiment, the relationship between surface tension of asphalt and temperature can be expressed as equation (2).…”

“…Water damage is mainly derived from the loss of the bonding between asphalt and aggregates, which is closely related to the viscosity and cohesion of asphalt, the alkalinity or acidity property, and the surface roughness of aggregates. Some authors demonstrated that moisture could damage the asphalt that lost in strength and durability due to the presence of water [1][2][3]. Now, the mechanism of bonding between asphalt and aggregates has become the hottest topic currently, and lots of researches have been conducted.…”

An experimental investigation of optimal asphalt–aggregate ratio for different compaction methods

“…Marshall stability, compressive strength, shear strength etc. [5][6][7]. The optimal A-A ratio is regarded as a density design criterion, which is evaluated by the air void of whole mixture in the volumetric design of super-pave [7,8].…”

Determination of the Chemical Composition in Asphalt Aqueous Solutions by SPE and GC/MS

“…The interaction process between asphalt pavement and water was the following: leaching of water, infiltrating of the road surface water into the pavement surface layer under the dynamic pressure, and moisturizing of groundwater (Petersen and Plancher, 1998;Cheng et al, 2003;Bagampadde et al, 2004;Bagampadde et al, 2006;Bagampadde and Kiggundu, 2007;Burak and Emine, 2007;Airey, 2008;Saeed, 2009). The chemical constituents in asphalt cement (AC) concrete could be leached in wet weather (Peter et al, 2001).…”